CFH rs2391191: Understanding the Genetic Context of AMD
The rs2391191 variant is a single nucleotide polymorphism located within the CFH gene region. It has been studied for its potential association with susceptibility to age-related macular degeneration (AMD), a complex eye condition affecting older adults.
What each genotype means
Typical AMD risk
You carry two copies of the common C allele for this CFH variant. Published genome-wide association studies show this genotype is associated with a baseline statistical likelihood of developing age-related macular degeneration (AMD). Having this genotype does not prevent eye disease, and overall risk depends heavily on lifestyle, age, and other genetic factors.
Found in approximately 30% to 40% of individuals of European ancestry and at varying frequencies globally.
Modestly altered AMD risk
You carry one copy of the T allele alongside one C allele in the CFH region. In population-level studies, the T allele has been associated with modest differences in susceptibility to age-related macular degeneration (AMD), though the clinical evidence specific to this single intronic marker is limited. This genetic result does not diagnose any visual disorder or determine personal disease onset.
Carried by approximately 45% to 50% of individuals across European populations.
Modestly altered AMD risk
You carry two copies of the T allele for this intronic CFH variant. Population research has reported limited associations between this genotype and altered risk of age-related macular degeneration (AMD), often reflecting linkage to broader CFH complement locus haplotypes. Because this marker is not definitively causal on its own, it is not used as an independent clinical diagnostic tool.
Observed in roughly 15% to 20% of people of European descent.
What is rs2391191?
The variant rs2391191 is a single nucleotide polymorphism (SNP) situated within the genomic region of the CFH gene on chromosome 1. In genetics, a SNP represents a variation at a single position in the DNA sequence among individuals. Because rs2391191 is located in an intronic region—a non-coding part of the gene—it does not directly alter the amino acid sequence of the protein produced by the gene. Instead, researchers investigate such variants to determine if they influence gene expression, regulation, or the stability of messenger RNA. While many variants in the CFH region have been identified, rs2391191 is one of several markers studied to understand the genetic architecture of complex diseases. It is important to note that the presence of a specific allele at this site does not function in isolation; rather, it is often analyzed as part of a larger haplotype or a cluster of variants that collectively contribute to the biological function of the complement system.
The Role of the CFH Gene
The CFH gene provides instructions for making a protein called complement factor H. This protein is a critical component of the complement system, which is part of the body's innate immune response. The complement system helps identify and eliminate pathogens, but it must be tightly regulated to prevent damage to the body's own healthy tissues. Complement factor H acts as a regulator, preventing the complement system from becoming overactive and causing inflammation or tissue injury. When the CFH gene is altered, the resulting protein may not function optimally, potentially leading to chronic, low-level inflammation. In the context of the eye, this dysregulation is hypothesized to contribute to the formation of drusen—small yellow deposits under the retina—which are a hallmark of age-related macular degeneration. Understanding how CFH variants influence protein levels or activity is a major focus of ongoing research into the mechanisms of vision loss.
Research and Evidence Strength
The association between the CFH gene and age-related macular degeneration (AMD) is well-established in scientific literature, particularly regarding variants like Y402H. However, the evidence for rs2391191 specifically is considered limited. While some studies have identified this variant in the context of AMD susceptibility, the statistical strength of its individual contribution is often less pronounced than that of other well-known coding variants in the same gene. AMD is a multifactorial condition, meaning it is influenced by a combination of genetic factors, environmental exposures, and lifestyle choices such as smoking and diet. Because of this complexity, it is difficult to isolate the effect of a single intronic SNP. Current research continues to explore how these variants interact with one another and with environmental triggers to influence disease risk. Consumers should view these findings as part of a broader, evolving scientific landscape rather than a definitive diagnostic tool for predicting individual health outcomes.
Interpreting Your Genetic Information
Genetic information regarding variants like rs2391191 is intended for educational purposes and should not be used to diagnose or predict the development of eye disease. Because AMD is a complex condition, having a specific genotype does not guarantee that an individual will or will not develop the disease. Many people with 'risk' alleles never develop AMD, and many without them do. If you are concerned about your vision or your family history of eye disease, the most effective step is to consult with an eye care professional, such as an ophthalmologist or optometrist. They can perform comprehensive eye exams to monitor your retinal health and provide personalized advice based on your clinical history. Avoid making health decisions based solely on raw genetic data, as these results lack the context of a clinical examination and the nuance of your overall health profile.
How common is this variant?
The minor allele frequency for rs2391191 is approximately 0.35-0.45 in European populations, indicating that the variant is relatively common across these groups.
Frequently asked questions
Is rs2391191 a direct cause of macular degeneration?
No, rs2391191 is not a direct cause of AMD. It is a genetic marker associated with susceptibility, meaning it may contribute to risk in combination with many other genetic and environmental factors.
Should I get tested for CFH variants?
Routine genetic testing for CFH variants is not currently recommended for the general public. Clinical diagnosis of AMD is based on eye examinations, not genetic screening.
Can I change my risk if I have this variant?
While you cannot change your genetics, you can manage modifiable risk factors for AMD. Maintaining a healthy diet, avoiding smoking, and getting regular eye exams are recommended by health organizations.
Where can I find more information on CFH and eye health?
You can find reliable information on the MedlinePlus Genetics website or through the American Academy of Ophthalmology. These resources provide evidence-based summaries on eye conditions and the role of genetics.
Sources & further reading
Educational information only, last refreshed 10/11/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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Get my report — $29Related variants in CFH
This variant in the complement factor H gene is associated with altered regulation of the alternative complement pathway and increased susceptibility to age-related macular degeneration.
This regulatory variant in the CFH locus is linked to complement system dysregulation and is a recognized genetic risk factor for age-related macular degeneration.
Common variant in the CFH locus strongly associated with risk of age-related macular degeneration (AMD).
Genomic marker in CFH frequently co-inherited in haplotypes modulating risk of late-stage visual loss from macular degeneration.
Intronic marker in CFH forming critical susceptibility haplotypes for choroidal neovascularization and macular atrophy.
Intergenic/intronic variant within the CFH cluster contributing to phenotypic variation in retinal complement activation.