A Closer Look at Color Blindness

Catherine on June 9, 2025

Close-up human eye representing color blindness and vision differences.

Disclaimer: This article is for informational purposes only and is not intended to diagnose any conditions. LifeDNA does not provide diagnostic services for any conditions mentioned in this or any other article.

Have you ever met someone who can’t tell red from green or struggles to distinguish certain shades? This condition is called color blindness, and for many people, it’s something they’re born with. Color blindness doesn’t mean seeing the world in black and white. Most people with color blindness can still see colors, just not in the usual way. 

The most common type is red-green color blindness, where someone has trouble telling the difference between those two colors. Less common types include blue-yellow color blindness and total color blindness, which is very rare. These conditions affect how the light-sensitive cells in the eyes work. But what causes it and is it mostly  genetic?

You may want to read: Genetics of Color Blindness

What Is Color Blindness?

Color blindness happens when your eyes don’t detect colors properly. This is usually because some of your cone cells, special nerve cells, called photoreceptors,  in your eyes are missing or don’t work well. Cone cells detect light and color. You normally have three types that respond to red, green, and blue light. When one or more types of cones don’t function as they should, your ability to see certain colors or shades becomes limited. Most people with color blindness can still see colors, just differently than others. Only very rare cases involve seeing only shades of gray.

You may want to read: Visual Acuity: Seeing Clearly Through Science and Genetics

Studies on Secondary Color Blindness

Not all cases of color blindness are inherited. Some people develop it later in life due to aging, eye injuries, certain diseases like diabetes or glaucoma, or as a side effect of medications. These are acquired forms of color blindness.

One study looked into how type II diabetes can affect color vision. It included 343 participants and examined 673 eyes using a test called the Farnsworth-Munsell 100 Hue Test. The findings share that about 43% of people with type II diabetes showed some form of impaired color vision , and the rates were nearly the same whether or not the person had diabetic retinopathy. Most of the color vision problems involved difficulty telling apart blue and yellow shades. 

However, when researchers used a special analysis technique called the moment of inertia, they didn’t find any consistent patterns, such as red-green or blue-yellow defects. This suggests that color confusion in diabetic individuals may be more random and severe rather than following typical color blindness types.

The study identified several other factors that were linked to a higher chance of having color vision problems. One of the most significant was clinically significant macular edema , which tripled the risk. People with higher intraocular pressure , even if still within the normal range, were also more likely to experience color vision loss. Another unexpected factor was elevated heart rate, which showed a weaker but still meaningful connection. While there were slightly higher rates of impaired color vision among women and those with certain types of cataracts (like posterior subcapsular cataracts), these weren’t strong enough to remain significant when other variables were considered. Together, these findings highlight that color vision issues in diabetes aren’t just tied to obvious eye disease, like diabetic retinopathy.

 

Color vision changes might not seem like a big problem at first, but they can have a serious impact on daily tasks. People with impaired color vision  may struggle with recognizing traffic lights, reading charts that use color coding, or picking out ripe fruits. These issues can also affect job performance in professions where color recognition is important. 

 

The study suggests that individuals with diabetes, especially those with macular swelling or higher eye pressure might benefit from functional vision testing and counseling. Even though these color vision problems might go unnoticed in a regular eye exam, they represent a real and often overlooked challenge in living with diabetes.

Is There a Cure for Color Blindness?

While there’s no cure for genetic color blindness, there are ways to manage it and adapt:

  • Color identification tools – Apps and devices can help label or recognize colors more accurately.
  • Special glasses or lenses – Some people benefit from glasses designed to improve contrast and enhance color differences, especially for red-green color blindness. These don’t work for everyone, but they can help in certain situations.
  • Adaptation strategies – Many people simply learn to rely on labels, organization, or pattern cues rather than color alone.

References:




The Genetics of Dyslexia

Catherine on June 8, 2025

Child with dyslexia surrounded by jumbled letters representing reading difficulty.

Disclaimer: This article is for informational purposes only and is not intended to diagnose any conditions. LifeDNA does not provide diagnostic services for any conditions mentioned in this or any other article.

For people with dyslexia, everyday reading tasks may feel like decoding a foreign language. It’s frustrating, especially when one’s effort doesn’t seem to match results. But the root cause isn’t a lack of will, it’s in how the brain interprets written language. Genetics is helping explain why some brains are simply built to learn and process information differently.

Affecting up to 10% of the population, dyslexia challenges traditional notions of learning because it’s not caused by a lack of effort or intelligence. Understanding these roots may help improve diagnosis and intervention.

What is Dyslexia? 

Dyslexia is a specific learning difficulty that primarily affects reading, spelling, and writing. Individuals with dyslexia often struggle with decoding words, recognizing written symbols, and processing phonological information or the sounds of language. These difficulties may appear despite normal intelligence and access to education.

While reading challenges are the most visible symptoms, dyslexia may also affect working memory, rapid naming, and processing speed. It’s a lifelong condition, but with the right strategies and support, people with dyslexia can thrive academically and professionally.

You may want to read: How Genetics Shape Spatial Attention: A Deep Dive into Cognitive Abilities

What Are The Symptoms of Dyslexia? 

Dyslexia affects people differently, but the following are some common symptoms:

  • Difficulty reading aloud or reading slowly: A person with dyslexia may read word by word, often struggling to sound out longer or unfamiliar words. This happens because their brain takes more time to connect letters with sounds.
  • Trouble spelling even simple words: Spelling can be inconsistent. A person might spell the same word differently in the same paragraph. This is due to difficulty remembering how words are built phonetically or visually.
  • Problems matching letters to sounds: This is called phonological processing. People with dyslexia may not recognize that the letter b makes the b sound. This makes it hard to sound out words when reading or spelling.
  • Confusing similar-looking letters These are called mirror letters and are often flipped. Some letters like  b and d, or p and q.  It’s not a vision problem, it’s a brain processing issue where the brain misinterprets orientation.
  • Difficulty remembering sequences (like the alphabet or days of the week): Some people with dyslexia have trouble recalling things in order. This affects learning the alphabet, spelling rules, and even instructions that follow steps.
  • Struggling with writing or organizing thoughts on paper
     Writing may appear messy or disorganized. A person might know what they want to say but struggle to put it in a clear order or find the right words to write down.
  • Trouble learning new languages
     Learning a second language relies on similar skills as reading: decoding, listening, and remembering sounds. For someone with dyslexia, this may feel especially overwhelming.

You may want to read: Is Math ability Determined by Genetics?

What Causes Dyslexia?

The causes of dyslexia are multifactorial, meaning they stem from both genetic and environmental influences. While educational settings and early childhood experiences may shape how dyslexia manifests, research confirms that inherited factors play a major role in its development.

The Genetics Behind Dyslexia

Genetic factors linked to dyslexia don’t just influence reading ability, they help shape how the brain develops in the first place. Research shows that the genes that are associated with dyslexia can affect areas in the brain that are important for recognizing sounds and connecting them to written words, especially on the brain’s left side.

Brain scans of people with dyslexia often show differences in specific regions involved in reading, such as the temporoparietal and occipitotemporal areas. These differences are tied to genes that guide how brain cells move and settle into place during development.

Genes such as DCDC2 and KIAA0319 help guide neurons to their proper places in the brain. When this process is disrupted, the brain’s reading circuits may not develop well. Imaging studies show that people with dyslexia often have weaker connections in key language brain pathways like the arcuate fasciculus. This may slow down how quickly the brain combines what it hears with what it sees, which is critical for reading smoothly.

While reading instruction and intervention programs may help boost reading skills, they don’t completely reverse these brain differences. This shows that genetic wiring has a long-lasting effect on how the brain processes language and reading, even when external support is provided.

T Twin studies provide some of the strongest evidence that dyslexia has a genetic component. Researchers often compare monozygotic (identical) twins, who share 100% of their genes, with dizygotic (fraternal) twins, who share about 50%. 

When one identical twin has dyslexia, the other is much more likely to have it too, more often than in fraternal twin pairs. This higher concordance rate among identical twins suggests that genes play a major role in the development of dyslexia. Heritability estimates from these studies range between 40% and 70%, meaning that genetics accounts for a significant portion of the risk. However, the fact that concordance is not 100% even in identical twins also shows that environmental factors, such as early language exposure, teaching quality, and home literacy, also influence whether and how dyslexia develops. Twin research has helped us understand that dyslexia is not caused by a single gene but a combination of genetic and environmental factors.

A recent genome-wide association study (GWAS) investigated the genetic basis of dyslexia by analyzing data from over 51,800 adults who reported being diagnosed with dyslexia and more than one million individuals without the condition. Participants answered a survey question asking whether they had ever been diagnosed with dyslexia, allowing researchers to compare genetic differences between those who answered “yes” and those who answered “no.” The sample included both men and women, with the average age being around 50 years.

The study identified 42 genetic regions strongly linked to dyslexia, all meeting strict standards for statistical significance. Another 64 regions showed potential links, suggesting they may also be involved but need further study. These results support the idea that dyslexia is a polygenic trait  influenced by a wide range of genes, not just a single one.

To see whether these genetic effects differed by age or sex, researchers analyzed subgroups. The results were remarkably consistent. Genetic similarity (max 1.0) was 0.91 between males and females, and 0.97 between younger and older adults. This means the genetic influence on dyslexia appears stable across age and sex, although  more of the younger adults reported having dyslexia. About 5.3% of people in their twenties said they were affected, compared to just 3.2% of those in their eighties. This may reflect increased awareness, improved screening, or changes in how dyslexia is diagnosed over time.

Can you Treat Dyslexia?

There is no known cure for dyslexia, but effective management strategies may improve outcomes:

  • Structured literacy programs that focus on phonics, decoding, and spelling are proven to help children and adults build reading skills.
  • Assistive technologies like text-to-speech software and audiobooks support reading and comprehension.
  • Individualized education plans ensure that students receive accommodations and tailored instruction.
  • Awareness and self-advocacy help individuals understand their learning style and seek the support they need.

References

 

PON1 and Your Body’s Detox System

Catherine on June 6, 2025

DNA strand highlighting the genetic basis of the PON1 enzyme in body detoxification.

Disclaimer: This article is for informational purposes only and is not intended to diagnose any conditions. LifeDNA does not provide diagnostic services for any conditions mentioned in this or any other article.

Our bodies are constantly exposed to harmful substances in the environment, from pesticides to pollution. Fortunately, we have natural defense systems designed to protect us from these toxins. One of these defenders is a gene called PON1, which produces an enzyme that plays a key role in detoxifying specific chemicals.

An enzyme is a type of protein that speeds up chemical reactions in the body. Think of enzymes as tiny helpers that keep biological processes running efficiently. In the case of PON1, the enzyme helps break down toxic substances into safer forms that the body can eliminate. However, not everyone has the same versions or amounts of this enzyme. These differences may affect how well your body handles toxic exposures.

Understanding how the PON1 enzyme works and how much of it your body makes, may offer insight into your ability to detox harmful chemicals. Some people inherit a more efficient version of the PON1 gene, while others may produce a less active form. This helps explain why some individuals are more sensitive to environmental toxins. 

You may want to read: The Role of Genetic Variations in Mercury Detoxification

What is PON1?

PON1 gene codes  for Paraoxonase 1, is an enzyme made in the liver and found in the blood attached to the HDL molecule known as the “good” cholesterol. 

High-density lipoprotein (HDL) exhibits cardio- and neuro-protective properties, which are thought to be promoted by PON1. Reduced levels of PON1 activity, characterized biochemically by elevated levels of homocysteine (Hcy)-thiolactone, oxidized lipids, and proteins modified by these metabolites, are associated with pathological abnormalities affecting the cardiovascular system (atherothrombosis) and the central nervous system (cognitive impairment and Alzheimer’s disease).

In addition to its role in cardiovascular and nervous system diseases by protecting the body from damage caused by oxidized fats, PON1 has many other antioxidant and detoxifying properties and can use several different substrates via its different types of enzyme activities (lactonase, arylesterase, aryldialkylphosphatase/paraoxogenase).  PON1 helps break down harmful chemicals, particularly organophosphates or OPs, a group of compounds commonly found in pesticides and nerve agents. 

How PON1 Detoxifies Harmful Substances

PON1 works alongside another group of enzymes called cytochrome P450, and together they convert harmful compounds, especially organophosphates—into less toxic forms the body can remove. Some of the key environmental harmful substances PON1 helps neutralize include:

  • Paraoxon: A breakdown product of the pesticide parathion. It inhibits acetylcholinesterase, an enzyme essential for nerve function, leading to dangerous nerve overstimulation.
  • Chlorpyrifos oxon: A toxic metabolite of chlorpyrifos, a common insecticide, that also impairs nerve signaling.
  • Diazinon oxon: A harmful version of diazinon, another widely used pesticide. It disrupts normal nervous system function.
  • Sarin and soman: Highly toxic nerve agents used in chemical warfare. Both inhibit acetylcholinesterase, causing severe and often fatal effects.

PON1 is especially active in the liver and blood, which are the body’s primary detoxification centers. The enzyme’s ability to break down these substances plays a critical role in protecting the nervous system and reducing toxic buildup.

The Role of Genetics

A study from California examined how people’s genes affect their ability to handle certain pesticides and what that means for their health. Researchers focused on PON1, the gene that helps break down chemicals like chlorpyrifos and diazinon, both widely used in agriculture.

They found that people living near farms that were using these pesticides were more likely to develop Parkinson’s disease if they had a version of the PON1 gene version called PON1-55 MM (variant L55M, SNP rs854560 genotype TT). This version produces less enzyme, reducing the body’s ability to detox these chemicals. The risk was even higher for individuals under 60, suggesting that early-life exposure may play a bigger role. Interestingly, there was no strong link between this PON1 variantand another pesticide called parathion, possibly because the body metabolizes it using other enzymes or other PON1 enzyme activities not affected by this SNP. 

This study shows that not everyone is equally protected from toxins. People with a less effective version of the PON1 gene may accumulate more harmful chemicals over time, increasing the risk of developing diseases like Parkinson’s. 

It’s a reminder that our genes and environment interact. For some individuals, living near farms or working with pesticides could be much more dangerous due to differences in how their detox system functions.

In another study, researchers examined 27 individuals who could detoxify pesticide byproducts diazoxon, chlorpyrifos-oxon, and paraoxon well. These substances are normally broken down by the PON1 enzyme in the liver and blood. The study found wide variation in detox rates among individuals: Diazoxon: up to 5.7-fold difference, Chlorpyrifos-oxon: up to 16-fold difference, and Paraoxon: up to 56-fold difference. This means some people were significantly better at clearing these toxins, especially paraoxon, than others.

These differences could be at least partly be explained by the PON-1 genetics. People with the PON1-192RR genotype (SNP rs662 CC homozygotes of Q192R) were more effective at detoxifying paraoxon and had higher activity against chlorpyrifos-oxon, but this did not apply to diazoxon. 

Detoxification of diazoxon seemed more dependent on environmental or likely unidentified genetic factors. Another key finding was that paraoxon was the hardest to detoxify. The liver broke down diazoxon and chlorpyrifos-oxon 55 and 65 times faster, respectively, compared to paraoxon. This slower detox rate helps explain why parathion, the pesticide that turns into paraoxon in the body, poses a greater health risk. Overall, the study highlights the complex relationship between genetics, enzyme activity, and environmental factors in determining how effectively the body removes harmful substances.

How PON1 Affects Health? 

Among the many genetic differences found in the PON1 gene, two common PON-1 variants have gained particular attention for their potential impact on health: the previously mentioned L55M and Q192R. The L55M variant refers to a change in the amino acid at position 55 of the PON1 protein, which may influence how much of the enzyme is produced and circulates in the bloodstream. Meanwhile, the Q192R variant has a role inthe enzyme’s function, specifically how well it can break down harmful substances such as a natural substrate oxidized low-density lipoprotein (LDL) and certain pesticides. 

Since both of the  L55M and Q192R, as well as other PON1 variants affect how active the PON1 enzyme is, individuals with different combinations of these gene variants may have varying levels of protection against oxidative stress and related diseases.

You may want to read: The Science Behind High-Density Lipoprotein: Genetics and Exercise Insights

Studies also suggest that the different versions of the Q192R variant  differ in their activity in neutralizing various harmful compounds. Because of this, people with different versions may have varying levels of protection against oxidative stress and the development of certain diseases. For example, a study done in Singaporean Chinese adults found that smokers with certain PON1 variants, specifically the Q192R (rs662-T) were more likely to develop coronary heart disease or CHD whereas the risk was higher for non-smokers with the PON-1 SNP rs3735590 . Therefore the PON1 gene variants associated with disease risk varied depending on smoking status. This suggests that the effect of PON1 on heart health is influenced by both genetics and environmental factors like smoking.

 

These findings point to a complex interaction between genes, lifestyle, and disease risk, an area that researchers still strive to  understand.

References




Genetics of Sickle Cell Anemia

Catherine on May 15, 2025

Close-up microscopic image of blood platelets and red blood cells, illustrating the cellular components involved in sickle cell anemia.

Disclaimer: This article is for informational purposes only and is not intended to diagnose any conditions. LifeDNA does not provide diagnostic services for any conditions mentioned in this or any other article.

Sickle cell anemia is a well-known inherited blood disorder. Around 300,000 babies are born with sickle cell disease each year worldwide. The majority of people with sickle cell disease live in sub-Saharan Africa, India, the Mediterranean region, and the Middle East. In the United States, about 100,000 individuals are affected by the condition. It is caused by a genetic mutation that changes the shape and behavior of red blood cells (RBCs), leading to a range of health problems. Understanding the genetics behind sickle cell anemia helps explain how the disease is passed down, why it varies in severity, and how genetic screening can be used to manage it.

What Causes Sickle Cell Anemia?

Sickle cell anemia is caused by a mutation in the HBB gene, which provides instructions for making a part of hemoglobin — the protein in red blood cells that carries oxygen. This mutation changes just one DNA base, replacing adenine (A) with thymine (T). As a result, a single amino acid in the hemoglobin protein changes from glutamic acid to valine at position 6 of the beta-globin chain. This altered form of hemoglobin is called hemoglobin S (HbS).

Also read: The Genetics of beta-Thalassemia

Importance of Hemoglobin

Hemoglobin is a vital protein found in RBCs, and its main job is to carry oxygen from the lungs to the rest of the body. Every cell needs oxygen to produce energy, and hemoglobin ensures that oxygen is delivered efficiently. Once it drops off oxygen, hemoglobin also helps carry carbon dioxide, a waste product, back to the lungs to be exhaled. 

Without enough healthy hemoglobin, the body’s tissues and organs don’t get the oxygen they need, leading to fatigue, weakness, and more serious problems. In short, hemoglobin keeps your cells alive and your body functioning properly.

Why the Shape of Red Blood Cells Matters

The shape of RBCs is important because it helps them do their job well. Normal RBCs are round and flexible with a flattened, disc-like shape. This shape gives them a large surface area to carry more oxygen and allows them to squeeze through tiny blood vessels without getting stuck or damaged.

 

In people with sickle cell anemia, hemoglobin S (HbS) sticks together when oxygen levels are low. This causes red blood cells to become stiff and take on a crescent or “sickle” shape. These misshapen cells can block blood flow, break apart easily (leading to anemia), and cause pain, organ damage, or stroke.

Inheritance Pattern: Autosomal Recessive

Sickle cell anemia follows an autosomal recessive inheritance pattern. This means a person must inherit two copies of the HbS gene mutation — one from each parent — to have the disease.

 

  • Sickle cell disease occurs when a person has two sickle cell genes (HbSS) (mutation in both HBB gene copies).
  • Sickle cell trait occurs when a person has one sickle cell gene and one normal gene (HbAS). These individuals usually don’t have symptoms or have very mild ones, but they can pass the mutation  to their children.

For two parents who both have sickle cell trait (one mutated copy), each child has:

  • A 25% chance of having sickle cell disease (HbSS),
  • A 50% chance of having sickle cell trait (HbAS),
  • A 25% chance of having normal hemoglobin (HbAA).

Genetic Variants and Disease Severity

Not all people with sickle cell disease have the same symptoms. Some differences are due to other genetic factors. For example:

 

  • People with HbSC disease (one HbS gene and one gene for hemoglobin C, another variant) usually have milder symptoms than those with HbSS.
  • People with sickle beta-thalassemia (one HbS gene and one beta-thalassemia gene) may have a range of symptoms depending on the severity of the beta-thalassemia mutation.
  • Variants in genes that affect fetal hemoglobin (HbF) levels, such as the BCL11A gene, can reduce disease severity. Higher HbF levels can help prevent red blood cells from sickling.

BCL11A Gene

The BCL11A gene plays a key role in sickle cell disease by controlling the type of hemoglobin the body produces. Normally, babies are born with HbF, which is later replaced by adult hemoglobin (HbA). In people with sickle cell disease, the adult hemoglobin includes a faulty version called HbS.

BCL11A acts as a repressor—it switches off the production of HbF after birth. Scientists have discovered that reducing or turning off BCL11A can reactivate HbF production, even in adults. Increasing HbF levels helps because fetal hemoglobin prevents sickling of red blood cells, reduces symptoms, and improves overall blood health.

For this reason, BCL11A is a major target in gene therapy approaches for treating sickle cell disease. By silencing or knocking down BCL11A, therapies can boost HbF production and help protect patients from the damaging effects of HbS.

In a 2020 pilot study six patients with sickle cell disease were monitored for at least six months after receiving BCH-BB694 gene therapy, which uses shmiR-based knockdown to reduce BCL11A expression. The therapy led to strong and stable increases in fetal hemoglobin (HbF), with 20.4% to 41.3% of total hemoglobin being HbF and 58.9% to 93.6% of red cells showing HbF expression. During follow-up, sickle cell symptoms were reduced or disappeared. The results support BCL11A inhibition as a promising strategy for increasing HbF and show that this gene therapy approach may offer a good balance between safety and effectiveness.

Diagnosis and Genetic Testing

Sickle cell anemia is usually diagnosed with a blood test, often done in newborn screening programs. The test checks for different types of hemoglobin, including HbS. If a child is found to have the disease or trait, follow-up genetic testing can confirm the diagnosis and help understand the type of sickle cell condition.

Carrier testing for sickle cell trait is also important for couples planning a family, especially if both partners are from high-risk populations. Genetic counseling can help them understand the risks and options.

Why Sickle Cell Trait Still Exists

The sickle cell gene mutation remains common in some regions because of a natural advantage it provides. People with sickle cell trait are more resistant to severe malaria, especially from Plasmodium falciparum. This survival benefit explains why the mutation has persisted in areas where malaria is or was widespread.

Conclusion

Sickle cell anemia is a classic example of how a single gene mutation can lead to a serious health condition when inherited in a specific way. Advances in genetics have deepened our understanding of the disease and opened doors to new treatments, such as gene therapy and precision medicine. With early diagnosis, ongoing care, and better genetic awareness, people with sickle cell disease can live longer, healthier lives.

Read about other genetic conditions:

 

References

  1. https://jamanetwork.com/journals/jama/article-abstract/2793821
  2. https://www.nejm.org/doi/full/10.1056/NEJMoa2029392
  3. https://pmc.ncbi.nlm.nih.gov/articles/PMC3545189/

Can Genetic Data Improve Statin Prescription?

Catherine on May 13, 2025

Close-up of a statin pill, representing the role of genetic data.

Disclaimer: This article is for informational purposes only and is not intended for diagnostic use. LifeDNA does not provide diagnostic reports on any traits discussed. Genetics is just one piece of the puzzle; please consult a healthcare professional for comprehensive guidance on any health condition.

Statins are among the most widely prescribed drugs globally. Statins are used to lower blood cholesterol levels and reduce the risk of cardiovascular disease. Despite their broad usage and proven efficacy, not everyone responds to statins in the same way. Genetic differences among individuals play a key role in determining how well statins work, how they are metabolized, and the risk of side effects. Understanding the genetic response to statins is a step toward more personalized and effective treatments for cardiovascular health.

How Statins Work

The primary goal of statins is to reduce blood cholesterol levels.

 

Cholesterol is made in the liver through a step-by-step chemical process that starts with a molecule called acetyl-CoA. Acetyl-CoA comes from the breakdown of fats and sugars. These molecules are combined and processed through a pathway called the mevalonate pathway. 

 

A key step in this process is controlled by an enzyme called HMG-CoA reductase. HMG-CoA reductase helps convert acetyl-CoA into mevalonate. Mevalonate is an early form (precursor) of cholesterol. From there, the body goes through several more steps to finally produce cholesterol. Cholesterol is an important component of cell membranes- the outermost layer of our cells. Cholesterol is also the starting point to make hormones, like testosterone and estrogen, and vitamin D.

However, as we all know by now, excess cholesterol, especially in the form of  low-density lipoprotein (LDL) cholesterol, often called “bad cholesterol,” can build up in the walls of your arteries over time. This buildup forms plaques that narrow the arteries and make them stiff. This condition is called atherosclerosis. If a plaque breaks open, your body treats it like an injury and sends platelets to the area. The platelets form a clot. This clot can block blood flow and lead to a heart attack or stroke. So, while cholesterol is essential for your body, having too much of it in the wrong places can seriously increase the risk of cardiovascular disease.

Statins function by inhibiting HMG-CoA reductase. By blocking this enzyme, statins reduce levels of LDL. Lowering LDL levels helps prevent the buildup of plaques in arteries, thus reducing the risk of heart attack and stroke.

Analyzing the Genetics

Several genetic studies have reported that around 9% of the treatment effect of statins can be explained by genetic variations. Several genetic markers have been shown to influence our response to statins. 

SLCO1B1 

The SLCO1B1 gene encodes a liver transporter protein. This protein helps statins enter liver cells where they exert their effect. A common variant, SLCO1B1 c.521T>C (rs4149056), reduces the function of this transporter, leading to increased blood levels of statins like simvastatin. Increased levels of statin in the blood can heighten the risk of statin-associated muscle symptoms (SAMS), including myopathy and, rarely, rhabdomyolysis.

 

A 2012 case-controlled study researchers studied over 5,000 older adults who took either statin pravastatin or a placebo for about three years. They focused on specific gene variations in LXRA and SLCO1B1. They found that the  SLCO1B1 variant rs4149056-C, was also linked to a weaker response to the drug. And people with this variant had a smaller drop in LDL cholesterol compared to those without it. 

CYP3A5

This gene encodes an enzyme that is involved in the metabolism of statins like atorvastatin, simvastatin, and lovastatin. Variations in this gene can alter how quickly statins are cleared from the body. Reduced-function alleles (such as CYP3A5*3) can result in higher plasma statin concentrations, increasing the risk of side effects but potentially enhancing efficacy.

 

A 2021 systematic review analyzed data from eight studies involving 1,614 patients to examine whether the specific genetic variation CYP3A5*3, is linked to a reduced enzyme function and increased statin levels in the blood. The analysis found that individuals with the CYP3A5 *3/*3 genotype had a 1.4 times higher risk of experiencing statin-related side effects compared to those with other genotypes. 

ABCG2

The ABCG2 gene encodes a transporter protein involved in drug clearance from the body. The rs2231142 (Q141K) variant is associated with higher statin concentrations in plasma, especially rosuvastatin, and may influence both efficacy and side effect profiles.

 

A 2024 systematic review analysed 15 studies involving over 34,000 people found that a specific genetic variant, the A-allele of ABCG2 rs2231142, affects cholesterol levels and statin response. People with this variant tend to have lower “good” HDL cholesterol and higher “bad” LDL and total cholesterol. However, in Asian individuals with high cholesterol (dyslipidemia), this same variant makes the statin rosuvastatin work more effectively at lowering lipid levels. The study suggests that this genetic difference has the most impact in Asian populations and that using rosuvastatin preventively in those with the variant could help lower the risk of developing coronary artery disease.

Statin Intolerance

Statin intolerance refers to the inability to tolerate statin medications, usually due to side effects that make continued use difficult or impossible. The most common symptoms are muscle-related, such as pain, weakness, or cramps (known as statin-associated muscle symptoms or SAMS). In some cases, people may also experience liver enzyme abnormalities, digestive issues, or headaches. It often leads to patients stopping the medication or reducing the dose, which may increase their risk of heart disease if cholesterol levels are not well managed by other means.

 

Genetic testing, particularly for SLCO1B1 variants, is being increasingly used to predict the risk of statin-associated side effects. For example, a 2023 study showed that people with the SLCO1B1 c.521C/C genotype are more likely to have problems with simvastatin.

 

The Clinical Pharmacogenetics Implementation Consortium (CPIC) provides guidelines for tailoring statin therapy based on SLCO1B1 genotype.

Toward Personalized Statin Therapy

Pharmacogenomic testing isn’t yet standard for all statin prescriptions, but its utility is growing. Patients with a history of side effects or those requiring high-intensity therapy could particularly benefit. Integrating genetic data with clinical information, such as age, liver and kidney function, and other medications, can help clinicians make more informed choices about which statin to prescribe, at what dose, and with what monitoring.

Conclusion

The genetic response to statins is a compelling example of how genomic insights can refine and personalize medicine. Variants in genes such as SLCO1B1, CYP3A4, CYP3A5, and ABCG2 can significantly influence how patients metabolize and respond to statins, affecting both efficacy and safety. As pharmacogenomic tools become more accessible and cost-effective, they are likely to become an integral part of routine cardiovascular care—ensuring that the right patient gets the right statin at the right dose.

References

  1. https://www.cell.com/cell-genomics/fulltext/S2666-979X(24)00351-3
  2. https://www.sciencedirect.com/science/article/abs/pii/S0021915011009348
  3. https://link.springer.com/article/10.1186/s12872-024-03821-2
  4. https://www.mdpi.com/2075-4426/11/7/677
  5. https://journals.lww.com/jpharmacogenetics/fulltext/2023/09000/Real_world_pharmacogenetics_of_statin_intolerance_.2.aspx
  6. https://cpicpgx.org/guidelines/cpic-guideline-for-statins/

Understanding Aortic Stenosis: The Aging Heart

Catherine on May 12, 2025

A detailed visual illustration of the human heart focusing on the aortic valve, showing the narrowing associated with aortic stenosis.

Disclaimer: This article is for informational purposes only and is not intended to diagnose any conditions. LifeDNA does not provide diagnostic services for any conditions mentioned in this or any other article.

Overview

As we age, certain changes inside the heart can quietly affect how well it pumps blood. These changes often go unnoticed until they begin causing symptoms or are discovered during routine checkups. In some cases, they result from health issues that develop in middle age or from rare conditions present at birth.

One common issue that can arise from these hidden changes is the narrowing of one of the heart’s main valves. This narrowing puts extra strain on the heart, making it harder to pump blood to the rest of the body. Over time, this may lead to symptoms like shortness of breath, fatigue, chest pain, or more serious complications. Understanding what causes Aortic Stenosis and how it progresses is key to managing it effectively.

What Is Aortic Stenosis?

Aortic stenosis (AS) is when the aortic valve, one of the main valves in your heart, becomes narrowed or stiff. Normally, this valve opens and closes with every heartbeat, letting blood flow from the left side of the heart (left ventricle) into the aorta, which carries blood to the rest of the body.

In AS, the valve doesn’t open fully. This makes it harder for the heart to pump blood through it. Over time, the heart has to work harder to push blood out, which can lead to heart muscle thickening, fatigue, shortness of breath, and eventually heart failure if not treated. AS can happen for different reasons, including birth defects or age-related wear and tear. That’s why physicians say it can be either congenital (from birth) or acquired (developed later in life).

Types of Aortic Stenosis

Congenital Aortic Stenosis: This type is something people are born with. The most common cause is called a bicuspid aortic valve, where the valve has only two flaps (cusps) instead of three. Because of this unusual shape, the valve can become stiff and narrow earlier in life. There is an even rarer condition having a valve with only one flap, and this usually causes even more serious problems and symptoms at a younger age.

Acquired Aortic Stenosis: This type usually happens as people get older. It occurs when a normal valve with three flaps slowly becomes stiff and narrow because of calcium building up on it. This process is often caused by aging and lifestyle factors like high blood pressure, high cholesterol, and smoking.

Symptoms of Aortic Stenosis

Aortic stenosis (AS) may often go unnoticed for many years because early on, the narrowing valve may not cause any obvious problems. However, as the valve becomes more restricted, symptoms typically start to appear, especially during physical activity. Common signs to watch for include:

  • Shortness of breath during activity: The narrowed valve limits the amount of oxygen-rich blood reaching the body, making it harder to breathe when moving or exercising.
  • Chest pain or pressure (angina): The heart must work harder to push blood through the tight valve, which can cause discomfort or pain in the chest.
  • Fatigue and low energy: With less blood being pumped out, the body receives less oxygen, leading to feelings of tiredness and weakness.
  • Dizziness or fainting (syncope): Reduced blood flow to the brain during exertion can cause lightheadedness or fainting spells.
  • Heart palpitations or irregular heartbeat: As the heart tries to compensate for the restricted blood flow, abnormal heart rhythms may develop.

These symptoms often signal that aortic stenosis has progressed to a moderate or severe stage. If left untreated, severe AS can become life-threatening, especially once symptoms appear. Early recognition and medical evaluation are crucial to managing the condition effectively.

What Causes Aortic Stenosis Diagnosed?

Aortic stenosis happens when the valve that controls blood flow from your heart to the rest of your body becomes narrow or stiff. This narrowing makes it harder for your heart to pump blood, which may lead to symptoms and heart problems.

There are several reasons why this valve may become damaged or narrowed over time. Understanding these causes helps explain how aortic stenosis develops and why it affects some people more than others:

  • Born With Valve Problems: Some people have heart valves that didn’t form normally before birth. For example, instead of having three flaps (cusps), their valve might have only two or even one. This can cause the valve to wear out faster and narrow earlier in life.

  • Calcium Buildup with Age: As people get older, calcium can slowly build up on the valve, making it stiff and less able to open fully. This is the most common cause in adults over 65.

  • Damage from Infections: If infections like strep throat or scarlet fever aren’t treated, the bacteria can travel to the heart valves and damage them due to a condition called rheumatic fever . The body’s immune system tries to fight the infection but ends up damaging the valve, causing it to become narrow many years later.

  • Other Health Conditions: Some rare diseases like Paget’s disease (which affects bones), kidney failure, and inherited conditions that cause high cholesterol can also harm the valve. Autoimmune diseases like lupus and rheumatoid arthritis may cause inflammation that damages the valve too.

  • Age-Related Calcification: As people age, calcium, a mineral that helps build strong bones and may build up on the aortic valve. This calcium buildup causes the valve to stiffen and lose flexibility. When the valve can’t open fully, less blood passes through, so the heart must work harder. This process is the most common cause of aortic stenosis in older adults.

  • Rheumatic Fever: This is a rare complication from untreated strep throat or scarlet fever infections. It causes inflammation and scarring in the heart valves, including the aortic valve. The scarring thickens the valve and prevents it from opening properly. While less common today in many countries, rheumatic fever still causes aortic stenosis in some parts of the world.

  • Lifestyle and Health Risks: High blood pressure, smoking, and high cholesterol can injure your heart valves and blood vessels over time, making the valve wear out faster, especially as you age.

Genetics on Aortic Stenosis 

The congenital bicuspid aortic valve (BAV), a common congenital heart valve condition where the valve has two flaps instead of three, is highly genetic, with heritability estimated as high as 89%. However, this condition is not caused by just one gene but likely involves multiple genes and environmental factors.

Research has identified mutations in several important genes linked to BAV, such as NOTCH1, which is involved in valve development and calcification, and the GATA family of genes (GATA4, GATA5, GATA6), which also influence valve formation. Mouse studies show that altering these genes affects valve development and can cause BAV or related heart problems.

BAV changes the blood flow through the valve, creating abnormal stress that causes early calcium buildup and valve stiffening, which can lead to aortic stenosis (AS) and enlargement of the aorta. This calcification is an active process, similar to bone formation, involving cells in the valve turning into bone-like cells. The abnormal blood flow in BAV patients causes increased wall stress in the aorta, which differs based on the specific BAV subtype, leading to variations in how quickly calcification and valve disease develop.

Apart from BAV, acquired AS occurs later in life, mostly due to age-related calcium buildup on a normal valve and other cardiovascular risk factors like smoking, high cholesterol, and high blood pressure. This degenerative calcification is complex and likely requires multiple risk factors to cause significant valve damage.

Simply lowering cholesterol may not be enough to stop or reverse valve damage once it has progressed, highlighting the need for more personalized and combination therapies.

How Is Aortic Stenosis Diagnosed?

Diagnosing aortic stenosis usually starts when a doctor hears a heart murmur during a routine check-up. A murmur is an unusual sound made by blood flowing through a narrowed valve.

To confirm the diagnosis and understand how severe the stenosis is, doctors use several tests, including:

  • Echocardiogram: This is the most important test. It uses sound waves to create moving images of the heart and valve. It shows how well the valve is opening and how much blood is flowing through it.
  • Electrocardiogram (ECG or EKG): This test records the electrical activity of the heart and helps check for any irregular heartbeats or signs of heart strain.
  • Chest X-ray: This can show if the heart is enlarged or if there is fluid buildup in the lungs due to heart problems.
  • Cardiac catheterization: In some cases, a thin tube is inserted into a blood vessel and guided to the heart to measure blood pressure inside the heart chambers and valves. This gives detailed information about valve function.
  • CT scan or MRI: These imaging tests can help when more detailed pictures of the heart and valve are needed.

Early diagnosis is important because it helps doctors monitor the condition and decide when treatment may be needed to prevent serious complications.

How is Aortic Stenosis Treated? 

Treatment depends on how serious the narrowing is and whether you have symptoms.

  • Monitoring Without Symptoms:  If your aortic stenosis isn’t causing any symptoms, your doctor may just want to keep an eye on it. This means regular checkups and tests to watch for any changes.
  • Medications: For mild cases or to help with symptoms, doctors might prescribe medicines. These can include blood thinners to prevent clots, diuretics to reduce fluid buildup, or medicines for high blood pressure or irregular heartbeats. However, medications do not fix the valve or stop the narrowing from getting worse, they just help manage symptoms.
  • Valve Repair: If the valve damage is limited, your doctor might suggest repairing it. This can be done through surgery where the doctor opens your chest to fix the valve directly. Another option is balloon valvuloplasty, where a small balloon is inserted through a blood vessel and inflated to widen the valve opening. This may improve symptoms but is usually a temporary solution until a valve replacement is performed.

 

References

Is Aortic Valve Calcification Genetic?

Catherine on May 10, 2025

A highlighted image of the heart showing aortic valve calcification, focusing on calcium buildup in the aortic valve area.

Disclaimer: This article is for informational purposes only and is not intended to diagnose any conditions. LifeDNA does not provide diagnostic services for any conditions mentioned in this or any other article.

The aortic valve is one of the heart’s key valves. It controls the flow of blood from the heart to the rest of the body. To do this job well, it needs to open and close smoothly with every heartbeat, about 100,000 times a day.

Over time, the valve’s structure may begin to change. In some people, this may even happen earlier than expected by a condition known as aortic valve calcification. When the valve becomes less flexible, it doesn’t open and close properly. This limits blood flow from the heart and forces the heart to work harder to pump blood through the narrowed valve.

Understanding how and why this happens is important not just for treating it, but for recognizing who may be at risk before serious complications develop. 

You may want to read: What Does Genetics Tell About Your Exercise Heart Rate Recovery?

What Is Aortic Valve Calcification?

Aortic valve calcification happens when calcium slowly builds up on the valve leaflets, causing them to stiffen and harden. Over time, this buildup can make the valve that would allow blood to leave the heart less flexible, often leading to a condition called aortic stenosis. Aortic valve calcification is more common in older adults, but some younger individuals may also develop it, raising the question of whether genetic factors are involved.

Symptoms of Aortic Valve Calcification

Often in the early stages, aortic valve calcification doesn’t cause any symptoms. Many people don’t realize they have it until the valve becomes more narrowed or stiff, which can affect how well the heart pumps blood.

As the condition progresses, these symptoms may appear:

  • Shortness of breath – You may feel like you can’t catch your breath, especially during exercise or when walking uphill. This happens because your heart has to work harder to push blood through the narrowed valve.
  • Chest pain or tightness – You might feel pressure, squeezing, or pain in your chest, especially when being active or under stress. This occurs when your heart doesn’t get enough oxygen-rich blood.
  • Fatigue or weakness – Everyday activities like climbing stairs or walking short distances might make you feel very tired or worn out. The body may not be getting enough blood and oxygen due to reduced heart function.
  • Dizziness or fainting – You may feel lightheaded or even pass out. This can happen because blood flow to the brain is reduced when the heart struggles to pump through a narrowed valve.
  • Irregular heartbeat or a racing heart – You might notice that your heart skips a beat, beats too fast, or feels like it’s fluttering. This is called an arrhythmia and can be caused by strain on the heart.

These symptoms usually develop slowly over time but should not be ignored. If you experience any of them, especially if you have a family history of valve problems it isimportant to talk to your doctor. Early diagnosis can lead to better care and help prevent complications.

What Causes Aortic Valve Calcification?

The exact cause of aortic valve calcification isn’t fully understood, but several factors are known to increase the risk. These include both biological processes and lifestyle influences:

  • Aging:  As we get older, calcium tends to accumulate in various body tissues, including the heart valves. Over time, this buildup can stiffen the aortic valve and affect its ability to open and close properly.
  • Chronic Inflammation:  Long-term inflammation in the body, often due to other underlying conditions or immune responses, may lead to damage and scarring in the valve tissue, creating an environment where calcium deposits can form more easily.
  • High Blood Pressure and High Cholesterol: Elevated blood pressure puts extra stress on the heart and valves, while high cholesterol can lead to fatty plaque buildup. Both can injure the valve, promoting calcification over time.
  • Kidney Disease: Kidney problems affect how the body balances calcium and phosphate. When this balance is off, it can lead to excess calcium in the blood, which may deposit on the valves.
  • Lifestyle Factors: Habits like smoking, a poor diet, and lack of physical activity contribute to vascular damage, inflammation, and poor heart health—all of which can increase the risk of valve calcification.

Despite these risk factors, some people still develop aortic valve calcification without any clear external cause, suggesting that genetic predisposition may also play a role.

Genetics on Aortic Valve Calcification

An early sizable genetic study provided strong evidence that aortic valve calcification (AVC) can be influenced by inherited factors. Conducted by researchers within the CHARGE (Cohorts for Heart and Aging Research in Genomic Epidemiology) consortium, the study examined genetic data from thousands of participants to discover which genes might be linked to calcium buildup in heart valves.

Researchers looked at more than 6,900 individuals for signs of AVC and more than 3,700 for mitral annular calcification using CT scans. All participants were part of long-term population studies and were primarily of white European ancestry. Their findings were later confirmed in multiethnic groups, including African-American, Hispanic-American, and Asian-American cohorts.

A genetic variant called rs10455872 in the LPA gene , which affects lipoprotein(a), or Lp(a), levels, was strongly associated with aortic valve calcification. Individuals with this variant had more than twice the risk of developing AVC compared to those without it. This gene variant was also linked to clinical aortic stenosis (a severe narrowing of the aortic valve) and a higher likelihood of needing aortic valve replacement.

The role of the rs10455872 in AVC has further been confirmed in several recent studies including a GWAS study performed in almost 1 million participants. A total of 32 genomic loci were found to be associated with AVC in this recent study, of which 20 had not been previously discovered. The earlier study also identified two genetic variants near the IL1F9 gene, which is involved in inflammation, as potentially linked to calcification at mitral annular valve,  another heart valve that separates the left atrium and left ventricle. However, these findings were not consistently replicated, so more research is needed on the role of this proinflammatory gene. 

Research has consistently shown that genetics, especially variation in the LPA gene, plays a significant role in whether someone develops aortic valve calcification. While aging and lifestyle are important factors, some individuals may inherit a higher risk due to their genetic makeup.

Understanding this connection may help identify people at risk earlier, follow their heart health more closely, and eventually develop treatments that lower the lipoprotein(a) or stop its harmful effects.

Who Is at Higher Risk?

Aortic valve calcification can affect anyone, but some individuals are more likely to develop it due to age, genetics, or certain other health conditions. Knowing your risk can help you take preventive steps and talk to your doctor about screening, especially if you fall into one or more of these categories. Those at higher risk include:

  • Older Adults (Usually Over Age 65)
     As people age, calcium naturally accumulates in body tissues, including the heart valves. This age-related buildup is the most common cause of aortic valve calcification.
  • People with a Family History of Heart Valve Disease
     If close relatives have been diagnosed with aortic stenosis or other valve problems, you may be genetically predisposed to similar conditions.
  • Individuals with High Lipoprotein(a) Levels
     Lipoprotein(a), or Lp(a), is a type of cholesterol that can contribute to plaque and calcium deposits in blood vessels and valves. Elevated levels are often inherited and increase the risk of valve calcification.
  • Those with Genetic Syndromes Affecting the Heart
     Certain inherited conditions, such as bicuspid aortic valve or Marfan syndrome, can alter the structure or function of the heart and make calcification more likely at an earlier age.

Can You Prevent Aortic Valve Calcification?

While you can’t change your genes or stop the natural aging process, you can lower your risk of aortic valve calcification by taking care of your overall heart health. Here are practical ways to help protect your valves:

  • Eat a Heart-Healthy Diet: Focus on foods low in saturated fat, sodium, and added sugar. A diet rich in fruits, vegetables, whole grains, lean proteins, and healthy fats supports cardiovascular health and helps prevent calcium buildup.
  • Keep Cholesterol and Blood Pressure in Check:  High cholesterol and hypertension can damage your heart valves over time. Regular checkups, medication (if prescribed), and lifestyle changes can help keep these under control.
  • Avoid Smoking:  Smoking accelerates vascular damage, increases inflammation, and contributes to plaque and calcium buildup. Quitting smoking is one of the most effective ways to protect your heart and valves.
  • Stay Physically Active:  Regular exercise strengthens the heart, improves circulation, and supports healthy blood pressure and cholesterol levels. Aim for at least 30 minutes of moderate activity most days of the week.
  • Manage Diabetes or Kidney Disease:  Both conditions can affect how your body handles calcium and other minerals. Good management through medication, diet, and regular monitoring reduces the risk of calcification and other heart-related issues.

These healthy habits not only support heart valve function but may also slow the progression of existing calcification, helping you maintain better heart health for longer.

References



Is There a Genetic Cause Behind Cataracts?

Catherine on May 8, 2025

Man receiving an eye check-up to screen for cataracts, a condition that may have hereditary or genetic causes.

Disclaimer: This article is for informational purposes only and is not intended to diagnose any conditions. LifeDNA does not provide diagnostic services for any conditions mentioned in this or any other article.

Having cataracts may feel like looking through a foggy window as  your vision becomes cloudy, colors look dull, and it gets harder to read or see clearly at night. While cataracts often happen as people get older, not everyone experiences them the same way. Some people start noticing changes earlier in life, especially if family members also had cataracts. This raises an important question. Can cataracts be passed down through genes?

Aging is the most common cause of cataracts, but genetics may also play a role. Understanding this connection matters because it may help you stay ahead of vision problems, motivate you to protect your eyes from sunlight and manage other health conditions, so that you can keep your eyesight as good as possible into an advanced age.

You may want to read: Genetics of Color Blindness 

What Are Cataracts?

A cataract occurs when the normally clear lens of the eye becomes cloudy. This clouding blocks light from passing through the lens properly, which results in vision problems. Many people describe it like looking through a foggy window. Cataracts are very common as you get older. In fact, more than half of all Americans age 80 or older either have cataracts or have had surgery to get rid of cataracts.

Congenital cataracts are rare as they happen only in about 72 out of every 100,000 children. About 8–25% of these cases are inherited, meaning it is possible that this condition may be passed down from parents to children. Congenital cataracts may appear on their own or as part of a syndrome involving other health conditions.

A cataract may develop slowly and may not affect vision at first. But over time, it may interfere with daily activities such as reading, driving, or recognizing faces. 

What Are the Types of Cataracts?

A cataract may develop in different parts of the lens, and each type can affect vision in a unique way. Understanding the types of cataracts can help explain how symptoms may vary from person to person.

Nuclear Cataracts: These form in the center of the lens and are the most common type associated with aging. In the early stages, they might actually improve your reading vision, a phenomenon known as “second sight.” However, over time, the lens becomes yellow or brown, making distance vision blurry and colors harder to distinguish.

Cortical Cataracts: Cortical cataracts begin as white, wedge-shaped streaks around the outer edge of the lens. As they progress, the streaks move toward the center, disrupting how light passes through the lens. This type often causes problems with glare and contrast, especially in bright light.

Posterior Subcapsular Cataracts: These form at the back of the lens, right in the path of incoming light. They tend to develop faster than other types and can interfere with reading, cause glare or halos around lights, and make vision in bright environments difficult. They’re often seen in people taking steroids or those with diabetes.

Congenital Cataracts: These are present at birth or develop in early childhood. They may be inherited or result from infections, trauma, or health conditions during pregnancy. Not all congenital cataracts affect vision, but if they do, early treatment is needed to prevent long-term vision problems.

What Causes Cataracts?

Most cataracts develop as a result of aging. As we grow older, the proteins and fibers in the lens of the eye begin to break down, causing cloudiness. But aging isn’t the only factor. Other causes of cataracts include:

  • Eye Injuries:  Trauma to the eye, whether from an accident, blunt force, or sharp object, may damage the lens and lead to cataract formation. Sometimes the cataract may appear soon after the injury, or it may develop years later as a result of internal damage or inflammation.
  • Previous Eye Surgery: Surgeries done to treat other eye problems, such as retinal disorders may increase the risk of developing cataracts later on. The procedure may disrupt the natural structure of the eye or trigger changes in the lens that lead to clouding.
  • Diabetes:  People with diabetes have a higher risk of cataracts due to prolonged high blood sugar levels, which may change the structure of the lens. These changes make the lens more likely to become cloudy over time, especially if blood sugar isn’t well controlled.
  • Long-Term Use of Corticosteroid Medications: Extended use of corticosteroids, whether taken orally, through inhalers, or as eye drops has been linked to cataract development. These medications can interfere with the normal function of the lens and speed up clouding, especially with high doses or long durations.
  • Prolonged Exposure to Ultraviolet (UV) Light: Spending long hours in the sun without eye protection may increase cataract risk. UV rays may cause damage to the proteins in the lens, leading to changes that result in cloudiness and impaired vision over time.
  • Smoking and Heavy Alcohol Consumption:  Smoking introduces harmful chemicals into the body that may damage the eye’s lens, while excessive alcohol intake may deplete antioxidants that help maintain eye health. 

You may want to read: How to Improve Eye Health Naturally With Vitamin A

Genetics on Cataracts

Studies show that certain genetic variants may influence whether a person develops cataracts early in life or later on with age. In some cases, the same gene is involved in both thecongenital (inherited) and age-related cataracts, depending on how serious the gene changes are. For example, changes in the GALK1 gene, which helps process sugars in the body, may cause cataracts in babies when both copies of the gene from the parents are affected. But even people who only carry one altered copy—like a parent of an affected child, may have a higher risk of developing cataracts as they age. One variation of this gene, called the “Osaka variant,” is linked to a higher rate of cataracts in Japanese adults.

Other genes also play a role. The SLC16A12 gene, which helps transport nutrients and waste, has mutations that may cause childhood cataracts along with other issues like sugar in the urine and small eye size. Milder variants in the same gene have been found in adults with age-related cataracts. Similarly, EPHA2, a gene involved in lens structure and development, is connected to both early-onset and age-related cataracts. One variant in this gene reduces its activity and may increase a person’s risk over time.

Another well-studied gene is CRYAA, which produces α-crystallin which is a a protein that helps keep the lens clear by preventing other proteins from clumping. A specific variation in this gene lowers its protective effect, making it harder for the lens to fight off damage, especially in older adults. This gene, along with others like SOX2, TMPRSS5, and BICRA, has been linked to nuclear cataracts, which affect the central part of the lens.

Researchers have also identified many other gene regions that might be linked to age-related cataracts, but these still need more study. Some of these include genes related to oxidative stress, inflammation, and cell repair, such as GSTM1, PARP1, MTHFR, and APOE. Genetic studies help us understand why some people are more likely to get cataracts than others even if they take good care of their eyes. These insights may one day lead to more personalized ways to prevent cataract development.

How Are Cataracts Linked to Diabetes?

Diabetes is associated with cataracts in adults. High blood sugar levels in people with diabetes can damage the lens over time. This may lead to earlier or more severe cataracts.

Diabetes Mellitus is a long-term health condition that affects how your body uses sugar. Over time, high blood sugar can harm different parts of the body, including the eyes. People with diabetes can get cataracts at a younger age than others. This is because too much sugar in the lens can turn into a substance called sorbitol. Sorbitol makes the lens swell and become cloudy. Diabetes also causes oxidative stress, which means that harmful molecules build up and damage the lens. Other things like changes in lens proteins and inflammation can also lead to cataracts. In some rare cases, people with type 1 diabetes may get cataracts very fast, possibly because of how the immune system reacts to insulin treatment.

The risk of cataracts is even higher for those who’ve had diabetes for many years or who struggle with frequent blood sugar spikes. Complications like macular edema, which involves fluid leakage in the retina, can further worsen vision problems.

Is Cataract Hereditary?

While not all cataracts are inherited, genetics may play a role in at what age you may be affected. If cataracts run in your family, it’s important to be proactive with regular eye checkups and healthy lifestyle choices. Understanding your family history, managing health conditions like diabetes, and protecting your eyes from UV exposure may all help maintain healthy vision as you age.

Can Cataracts Be Prevented?

While there’s no guaranteed way to prevent cataracts, there are steps you can take to reduce your risk or slow their development:

  • Eat a nutrient-rich diet full of fruits and vegetables: Fruits and vegetables are packed with vitamins, minerals, and antioxidants that support overall eye health. Nutrients like vitamin C, vitamin E, and lutein may help protect the lens from damage that can lead to cataracts. A healthy diet helps the eyes stay strong as you age.
  • Wear sunglasses that block UV rays: Wearing sunglasses that protect against ultraviolet (UV) rays can help shield your eyes from sun damage. UV exposure is linked to a higher risk of cataracts, so using proper sunglasses—especially when outdoors—acts like sunscreen for your eyes.
  • Manage diabetes and other chronic health conditions: Keeping diabetes and other medical issues under control is important for your eyes. High blood sugar levels can harm the lens and increase the chance of cataracts. Following your treatment plan and monitoring your condition can help prevent long-term eye damage.
  • Avoid smoking and reduce alcohol consumption: Smoking and heavy drinking can weaken your body’s natural defense systems and harm the lens of your eyes. By quitting smoking and limiting alcohol intake, you lower your risk of developing cataracts and support healthier vision as you age.

 

References



Is There a Genetic Reason Behind Sjögren’s Syndrome?

Catherine on May 8, 2025

A woman standing by a window, looking outside thoughtfully—capturing the emotional and reflective experience of living with a chronic autoimmune disease like Sjögren’s syndrome.

Disclaimer: This article is for informational purposes only and is not intended to diagnose any conditions. LifeDNA does not provide diagnostic services for any conditions mentioned in this or any other article.

Sjögren’s syndrome is a health condition that affects the parts of your body that are moist, like your eyes and mouth. Most people diagnosed with Sjögren’s syndrome are over the age of 40. But does that mean it only affects older adults? While it’s more common in people over 40, younger adults and even children can also develop the condition. That’s why it’s important not to overlook early symptoms, no matter your age.

Women are up to 10 times more likely to be diagnosed. Researchers believe this might have something to do with hormones, especially estrogen which may affect how the immune system works. This helps explain why many autoimmune diseases, including Sjögren’s, are more common in women.

By understanding who is more likely to develop Sjögren’s, whether based on age, gender, or other risk factors, we can pay attention to the signs earlier. Early diagnosis can lead to quicker access to proper care, which may greatly improve a person’s comfort, health, and quality of life.

What Is Sjögren’s Syndrome?

Sjögren’s syndrome is an autoimmune disease. This means the immune system, which normally protects your body from infections, mistakenly attacks your own healthy tissues. In this condition, the immune system mainly targets the glands that produce tears and saliva. These glands are important for keeping your eyes and mouth moist. When they are damaged, your body can’t make enough tears or saliva, leading to dryness. 

Dry eyes may cause stinging, itching, blurry vision, or a gritty feeling, like something is stuck in your eye. A dry mouth can feel sticky or chalky, and it may make it harder to speak, eat, or swallow. Without enough saliva, it’s also easier to get cavities or mouth infections.

Why Are Moisture Glands Important?

Moisture glands play a big role in keeping parts of the body comfortable and working well. Tear glands help protect and clean the eyes. Tears wash away dust and keep the eyes smooth so you can see clearly. Without enough tears, your eyes may become irritated, feel gritty, or look red and tired. You may also find it hard to be around bright or flashing lights.

Saliva glands help with speaking, chewing, swallowing, and tasting food. Saliva also protects your teeth and gums from harmful bacteria. When there’s not enough saliva, your mouth may feel dry or sticky. You might have trouble eating dry foods, notice a change in taste, or develop bad breath. Over time, dryness can lead to tooth decay, gum disease, or infections in the mouth.

Because of these reasons, the moisture glands are very important to your everyday health and when they don’t work properly, as in Sjögren’s syndrome, many small but important things in daily life can become more difficult.

What Are the Symptoms of Sjögren’s Syndrome?

Sjögren’s syndrome can cause a range of symptoms, from mild to more serious. These can affect different parts of the body and may develop slowly over time.

Most common symptoms:

  • Dry eyes: Burning or stinging sensation or itchy or gritty feeling, blurry vision, or sensitivity to light.
  • Dry mouth: It may feel like there is difficulty speaking, chewing, or swallowing. Some may feel changes in taste.

Other possible symptoms (when the condition affects more than the glands):

  • Joint and muscle pain – stiffness or soreness, especially in the morning
  • Fatigue – extreme tiredness that doesn’t improve with rest
  • Dry or itchy skin – may lead to rashes
  • Tingling or numbness – often in hands or feet
  • Chronic cough or hoarseness – if lungs or vocal cords are involved
  • Vaginal dryness – which can cause discomfort for women
  • Swollen salivary glands – particularly around the jaw or neck

You may want to read: Unveiling the Genetics of Skin Dryness


It is important to note that symptoms vary from person to person, and not everyone experiences all of them. Some people only have mild dryness, while others may have full-body symptoms that impact daily life.

What Causes Sjögren’s Syndrome?

Sjögren’s syndrome is caused by a mix of genetic and environmental factors. This means that a person may be born with certain genes that make them more likely to develop the condition, but something in their environment like a viral or bacterial infection might trigger it to actually begin. 

These infections may activate the immune system, and in people who are more sensitive, that immune response may not shut off properly. Instead, like in Sjögren’s Syndrome, the immune system starts attacking the body’s own healthy tissues, especially the glands that make moisture. This mistaken attack is what leads to symptoms like dry eyes and dry mouth. Although researchers believe genes play a role, no single genetic change has been directly linked to causing Sjögren’s syndrome. Instead, it is likely that many small changes in different genes may add up, and increase a person’s risk.

Genetics on Sjögren’s Syndrome

Studies on Sjögren’s Syndrome noticed as early as in the 1940s, that this condition seemed to affect more women than men,  and that it involved the whole body, not just the eyes and mouth. By the 1970s, a link between immune system genes, specifically the HLA genes, and autoimmune diseases was acknowledged. In the early 1980s, researchers confirmed genetic differences in people with primary Sjögren’s Syndrome which appears on its own, without any other autoimmune condition. To this day, HLA gene variants remain the strongest known genetic risk factor for Sjögren’s Syndrome. Other gene variations have been found, but they appear to have only a mild to moderate impact.

 

Even though Sjögren’s Syndrome is one of the most common autoimmune conditions, progress in understanding its genetics has been slow compared to diseases like lupus or type 1 diabetes. Most studies have focused on gene variations already linked to other autoimmune conditions, but these studies often involve small groups of people in specific populations making the findings hard to repeat in other groups. However, newer tools like genome-wide association studies (GWAS) and next-generation sequencing are now helping researchers explore both genetics and epigenetics;how genes are turned on or off. These tools may also help explain problems in the immune system that affect people with Sjögren’s Syndrome (SS).

 

An early GWAS study by the Silvis group in the U.S., looked at DNA from 10,000 people (some with Sjögren’s Syndrome, some healthy), all of European descent. They found that the HLA region had the strongest link to SS, but six other genetic locations also showed strong associations: IRF5-TNPO3, STAT4, IL12A, FAM167A-BLK, DDX6–CXCR5, and TNIP1. Another 29 regions were found to have a possible association, including genes like TNFAIP3, PRDM1, and FCGR2A.

 

A second large GWAS study on SS was done in Han Chinese populations. It confirmed some of the same genetic links, such as STAT4 and TNFAIP3, but also found a new gene called GTF2I that was linked to Sjögren’s Syndrome in this group. Interestingly, some gene variations found in Europeans were not significant in the Chinese group. This shows that different populations may have different genetic risk factors for Sjögren’s Syndrome, and it’s important to study people from many ethnic backgrounds.

 

One important finding from both of these early studies is that no single gene was found to have a strong effect like those seen in other diseases. The genetic changes found in these studies did  not seem to  directly affect the working parts of the glands that are damaged in Sjögren’s Syndrome like the salivary and tear glands. New research using better tools, and larger groups of people are helping  to better understand how both the immune system and the glands are involved in this condition.

 

You may want to read: What You Need to Know About the Genetics of Lupus

How Is Sjögren’s Syndrome Treated?

There is no cure for Sjögren’s syndrome, but the good news is that symptoms can be managed with the right treatment. Doctors focus on relieving dryness, protecting your teeth, and reducing pain or fatigue.

  • For dry eyes:  To keep your eyes comfortable, you can use artificial tears, gels, or ointments to add moisture. If dryness is more severe, prescription eye drops may help reduce inflammation and boost natural tear production. Simple habits like wearing sunglasses and using a humidifier at home can also help protect your eyes from becoming too dry.

  • For dry mouth: Sipping water regularly throughout the day can ease dryness. Chewing sugar-free gum or sucking on sugar-free candies can help stimulate saliva. There are also saliva-replacement products and prescription medications that your doctor may recommend to support moisture. Because dry mouth can increase your risk of cavities and oral infections, brushing, flossing, and visiting the dentist regularly are especially important.

  • For joint pain and body inflammation: Mild pain can often be managed with over-the-counter medications like ibuprofen. In some cases, doctors may prescribe hydroxychloroquine, a medication commonly used for autoimmune conditions. If symptoms are more serious, stronger immune-suppressing drugs may be needed to reduce inflammation and prevent further damage.

  • For tiredness (fatigue): Many people with Sjögren’s feel unusually tired. Getting enough rest and keeping a regular sleep routine can make a big difference. Eating a well-balanced, healthy diet supports energy levels, and gentle activities like stretching, walking, or yoga can help fight fatigue and keep the body moving without strain.

References: 

 

The Genetic Connections in Graves’ Disease

Catherine on May 7, 2025

Woman with a red-highlighted neck, symbolizing thyroid inflammation — a key feature of Graves’ disease, which has known genetic links.

Disclaimer: This article is for informational purposes only and is not intended to diagnose any conditions. LifeDNA does not provide diagnostic services for any conditions mentioned in this or any other article.

Just below your voice box is a small, seemingly quiet gland with a big job…controlling how your body uses energy, among other jobs. This is the thyroid, and when it becomes too active, such as in Graves’ disease, it may throw your whole body off balance. 

The immune system can mistakenly attack the thyroid, causing it to make too little or too much of the thyroid hormone.  A hormone overload in Graves’ disease may speed up your heart, make it hard to sleep, cause weight changes, and even affect your eyes. Knowing how Graves’ disease works may help people notice  the signs early and get the right treatment.

What Is Graves’ Disease?

When the thyroid gland becomes too active, as in Graves’ disease, it can throw your whole body off balance. In Graves’ disease the immune system mistakenly attacks the thyroid, causing it to produce too much thyroid hormone. This overload of hormones affects many systems in the body, from your metabolism to your heart, eyes, and skin.

Graves’ disease is the most common cause of hyperthyroidism (an overactive thyroid) and typically develops in people under 40, though it can appear at any age. It affects more women than men and often runs in families.

What Are the Main Symptoms of Graves’ Disease?

Graves’ disease affects many parts of the body, and the symptoms can show up in different ways for different people. Here’s what each common symptom means, in simple terms:

  • Fast or Irregular Heartbeat: Your heart may beat faster than normal or skip beats, even when you’re resting. It might feel like your heart is racing or pounding in your chest.
  • Weight Loss Even If You’re Eating Normally or More: You may lose weight without trying, even if you feel hungry all the time and eat more than usual. That’s because your body is burning energy too quickly.
  • Feeling Nervous, Anxious, or Moody: You might feel restless, jumpy, or worried all the time. You could also get irritated or upset more easily than usual.
  • Shaky Hands or Fingers: Your hands might tremble slightly, especially when you hold them out in front of you. This is because your body is on “high alert” from too much thyroid hormone.
  • Trouble Sleeping: You may have a hard time falling asleep or staying asleep. Even after sleeping, you might still feel tired.
  • Too Much Sweating or Feeling Hot All the Time: You might sweat more than usual or feel overheated, even in cool weather or air conditioning.
  • Going to the Bathroom More Often: You might need to have bowel movements more often than normal, or you may have mild diarrhea.
  • Feeling Tired or Weak: Even though your body is working overtime, you can feel very tired or worn out. Your arms or legs might feel weak, especially when climbing stairs or lifting things.
  • Lighter or Fewer Periods (for Women): Women may notice their periods are lighter, come less often, or sometimes stop altogether. This can also make it harder to get pregnant.
  • Swelling in the Neck (Goiter): The thyroid gland in your neck may get bigger. This can cause a lump or swelling at the base of your neck, and sometimes it can feel uncomfortable or make swallowing harder.

What Causes Graves’ Disease?

Graves’ disease happens when the immune system mistakenly attacks the thyroid gland, causing it to produce too much hormones. While the exact cause isn’t fully known, both genetic and environmental factors play a role.

Certain life experiences and habits can trigger Graves’ disease in people who are genetically prone. High stress or major life changes can affect the immune system, increasing the risk. Smoking is another important factor, it not only raises the chance of developing Graves’ disease but also makes eye problems related to the disease worse. Other environmental influences may also play a role, but these are the most well-known.

Genetics on Graves’ Disease

Family and twin studies show that genetics play a major role, accounting for 60-80% of the risk. A recent review has gathered findings from multiple genetic studies, starting from early candidate gene research to recent large-scale genome-wide studies involving diverse populations from East Asia and Europe. Key immune function genes such as HLA, CTLA4, and PTPN22 significantly influence susceptibility to Graves’ disease . Genetic variations may also be linked to important clinical features like age of disease onset and severity, thyroid enlargement or goiter, relapse after treatment, and eye complications. 

Overall, Graves’ disease is inherited as a complex genetic trait with over 80 genetic risk factors identified so far. Further large-scale research is needed to better understand how these genetic differences affect disease outcomes and in order to develop more personalized treatment strategies.

Can Graves’ Disease Affect the Eyes?

Around 25 to 50 percent of people with Graves’ disease develop eye problems, a condition known as Graves’ ophthalmopathy. These eye issues can include:

  • Redness, dryness, or irritation
  • Puffy eyelids
  • A feeling of grit or sand in the eyes
  • Bulging eyes (exophthalmos)
  • Light sensitivity
  • Blurred or double vision

In rare cases, the condition may lead to vision loss due to pressure on the optic nerve. Eye symptoms may appear before, during, or after other symptoms of hyperthyroidism.

How Is Graves’ Disease Diagnosed?

Diagnosing Graves’ disease begins with a detailed review of the symptoms and medical history, followed by a physical exam. Because Graves’ affects the thyroid gland and the immune system, doctors use several tests to confirm the diagnosis and understand the severity.

  • Blood Tests: The first step is usually a blood test to measure thyroid hormone levels (T3 and T4) and thyroid-stimulating hormone (TSH). In Graves’ disease, thyroid hormone levels are high while TSH levels are low. Doctors may also check for specific antibodies called thyroid-stimulating immunoglobulins (TSI) that trigger the thyroid to produce excess hormones.
  • Imaging Tests: An ultrasound of the thyroid gland can show if the gland is enlarged or has nodules. A radioactive iodine uptake or RAIU scan may also be used to see how much iodine the thyroid is absorbing—high uptake often points to Graves’ disease.
  • Eye Exam: Because Graves’ can affect the eyes, an eye specialist might evaluate for symptoms like swelling, redness, or bulging, helping to detect Graves’ ophthalmopathy.

Early and accurate diagnosis helps guide effective treatment and prevents complications, so it’s important to consult a healthcare provider if you notice telltale symptoms like a fast heartbeat, unexplained weight loss, or eye changes.

Can Graves’ Disease Be Cured?

Graves’ disease can often be managed successfully, but it’s not always curable. Some treatments, like radioactive iodine or surgery, may lead to hypothyroidism or an underactive thyroid, which then requires lifelong thyroid hormone replacement therapy. With the right treatment and regular follow-ups, most people may lead healthy, active lives.

What Are the Treatment Options for Graves’ Disease?

Treatment for Graves’ disease aims to lower the excessive thyroid hormone levels and relieve symptoms. The best approach depends on the person’s health, age, and how severe the disease is. Here are the most common treatment options, explained simply:

  • Anti-thyroid medications: These work by blocking the thyroid gland’s ability to make thyroid hormones. These medicines help bring hormone levels back to normal and reduce symptoms. They are often the first choice, especially for younger patients or those with mild to moderate symptoms. However, they may take several weeks to work and need to be taken regularly.
  • Radioactive iodine therapy: Uses a small dose of radioactive iodine, taken by mouth. The iodine is absorbed by the thyroid gland and slowly destroys the overactive thyroid cells, reducing hormone production over time. This is a common and effective treatment, but can cause the thyroid to become underactive, meaning patients may need to take hormone replacement pills for life.
  • Beta-blockers: These don’t affect thyroid hormone levels directly, but they help control symptoms like a fast or irregular heartbeat, shaking hands, and anxiety. They work by blocking the effects of thyroid hormones on the heart and nervous system, providing quick relief while other treatments take effect.
  • Surgery (thyroidectomy): This involves removing part or all of the thyroid gland. This option is usually for people with large goiters causing discomfort or trouble swallowing, those who don’t respond well to other treatments, or when thyroid cancer is suspected. Surgery quickly stops hormone overproduction but usually requires lifelong hormone replacement afterward.
  • Steroids or special eye drops:  For people with Graves’ ophthalmopathy (eye problems caused by Graves’ disease), doctors may prescribe steroids to help reduce inflammation and swelling behind the eyes, while eye drops relieve dryness and irritation. In severe cases, other treatments or surgery may be needed to protect vision.

Each treatment has its benefits and risks, and doctors choose the best plan based on your specific situation. It is important to work closely with your healthcare team to find the right approach for you.

References

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