HTRA1 rs11200638: What Your Genotype Means
The rs11200638 variant is a single-nucleotide polymorphism located in the promoter region of the HTRA1 gene on chromosome 10. It is widely studied for its statistical association with an increased risk of developing neovascular age-related macular degeneration (AMD).
What each genotype means
Lower macular degeneration risk
This genotype is associated with a lower statistical risk of developing age-related macular degeneration compared to those carrying the A allele. Research indicates this variant in the HTRA1 promoter region is a major susceptibility factor, and the G allele is generally considered the protective or non-risk version in this context.
Carried by approximately 36% to 60% of individuals depending on ancestral background, as the A allele is common in many populations.
Increased macular degeneration risk
Carrying one copy of the A allele is associated with an increased statistical susceptibility to age-related macular degeneration. Studies suggest this variant may influence the expression of the HTRA1 enzyme, though the exact biological mechanism remains a subject of ongoing research.
This heterozygous genotype is common, appearing in a significant portion of both European and East Asian populations.
Higher macular degeneration risk
This genotype is strongly associated with an increased risk of developing neovascular age-related macular degeneration. While this genetic association is well-documented in scientific literature, it is not a diagnosis; you should discuss your overall eye health and any vision concerns with an eye care professional.
The A allele is frequent, with the homozygous AA genotype found in a substantial percentage of the population, particularly in East Asian and European cohorts.
Understanding the Variant and Its Location
The rs11200638 variant is a genetic change where a guanine (G) is replaced by an adenine (A) in the promoter region of the HTRA1 gene. This gene is situated on the long arm of chromosome 10, specifically at the 10q26 locus. This region is a well-known "hotspot" for genetic research because it contains several genes, including HTRA1 and the neighboring ARMS2 gene, that have been linked to eye health. Because these genes are located very close to one another on the chromosome, they are often inherited together as a block, a phenomenon known as linkage disequilibrium. This makes it challenging for researchers to determine whether rs11200638 itself is the direct cause of disease risk or if it is simply a marker that is inherited alongside other, more influential genetic changes in the immediate vicinity.
The Role of the HTRA1 Gene
The HTRA1 gene provides instructions for making a protein called HtrA serine peptidase 1. This protein functions as a secreted serine protease, which is an enzyme that breaks down other proteins. In the context of the eye, researchers have investigated whether this protein plays a role in maintaining the health of the retinal pigment epithelium, a layer of cells that supports the light-sensing retina. Some early studies hypothesized that the risk-associated version of the rs11200638 variant might lead to the overproduction of the HTRA1 protein, potentially causing damage to the delicate structures of the eye. However, this hypothesis remains a subject of significant scientific debate. Other researchers have argued that the neighboring ARMS2 gene, rather than HTRA1, is the primary driver of disease risk in this region, suggesting that the biological mechanisms behind AMD are more complex than a single gene effect.
Research Associations and Evidence Strength
The evidence linking rs11200638 to age-related macular degeneration is considered strong in terms of statistical association, but the functional evidence is mixed. Numerous studies have confirmed that individuals carrying the risk allele show a higher statistical likelihood of developing neovascular (wet) AMD. However, the scientific community has not reached a consensus on the exact mechanism. While some studies reported that the variant increases HTRA1 expression, other independent investigations failed to replicate these findings in laboratory cell models. Furthermore, because rs11200638 is in strong linkage disequilibrium with variants in the nearby ARMS2 gene, it is difficult to isolate the specific contribution of this SNP. Consequently, while the association is robust in population-based studies, the biological role of this specific variant in the pathogenesis of macular degeneration remains an area of active, ongoing research.
What This Information Means for You
Genetic information regarding rs11200638 provides insight into your statistical predisposition for age-related macular degeneration, but it is not a diagnostic tool. AMD is a multifactorial condition influenced by a combination of genetics, environmental factors, and lifestyle choices, such as smoking and diet. Knowing your genotype for this variant does not mean you will definitely develop the condition, nor does the absence of the risk allele guarantee protection. This information should not be used to make medical decisions or to predict individual health outcomes. If you are concerned about your vision or your family history of eye disease, the most appropriate step is to consult with an ophthalmologist or a genetic counselor. They can provide personalized guidance based on your clinical history and perform necessary screenings to monitor your eye health over time.
How common is this variant?
The A allele is relatively common, with a frequency of approximately 0.40 in European populations and 0.42 in East Asian populations.
Frequently asked questions
Does having the rs11200638 risk allele mean I will get AMD?
No. Genetic variants like rs11200638 only indicate a statistical increase in risk. Many people with the risk allele never develop AMD, and many people without it do.
Is rs11200638 the only genetic factor for AMD?
No. AMD is a complex disease influenced by many different genetic variants across the genome, as well as environmental factors like smoking and age.
Should I get tested for this variant?
Routine genetic testing for this variant is generally not recommended for the general public. Clinical eye exams are the standard for monitoring and managing macular health.
What is the difference between HTRA1 and ARMS2 in AMD?
Both genes are located in the same region on chromosome 10 and are linked to AMD risk. Scientists are still debating which gene is the primary driver of the disease.
Sources & further reading
Educational information only, last refreshed 10/14/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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