CYP1B1 rs28936680: What Your Genotype Means
The genetic variant rs28936680 is a missense mutation located within the CYP1B1 gene. It is recognized as a founder mutation associated with an increased risk for early-onset, recessive forms of infantile and juvenile glaucoma.
What each genotype means
Typical CYP1B1 profile
This genotype represents the common or wild-type version of the CYP1B1 gene at this position. It is not associated with the increased risk for early-onset glaucoma attributed to the variant allele.
This is the most common genotype observed across all global populations.
Genetic carrier status
You carry one copy of the variant allele and one copy of the common allele. Because this condition is inherited in a recessive manner, carriers typically do not experience symptoms of CYP1B1-related glaucoma, but they may pass the variant allele to their biological children.
Carried by a small percentage of the population, with higher frequencies observed in specific Middle Eastern and other founder-effect cohorts.
Increased risk for glaucoma
This genotype indicates you carry two copies of the variant allele. Research identifies this as a potential cause of early-onset recessive infantile and juvenile glaucoma, as it may result in an unstable or dysfunctional CYP1B1 enzyme, which is critical for normal eye development. Please discuss this finding and any relevant clinical history or eye health concerns with your healthcare provider or a genetic counselor.
Very rare in the general global population, though more frequently identified in specific ancestral groups where this founder mutation is present.
Understanding rs28936680: A Deep Dive into the CYP1B1 Gene
The genetic variant rs28936680 is a specific change within the DNA sequence, identified by its reference single nucleotide polymorphism (SNP) ID. It is located in the CYP1B1 gene, which stands for Cytochrome P450 Family 1 Subfamily B Member 1. This gene plays a critical role in the body, primarily involved in the metabolism of various endogenous and exogenous compounds, including certain hormones and environmental toxins. Its protein product, the CYP1B1 enzyme, is particularly important in the development and function of the eye. The specific mutation at rs28936680 is a missense mutation, meaning it alters a single amino acid in the CYP1B1 protein, potentially affecting its structure and function.
The Link Between rs28936680 and Glaucoma
Research has established a strong association between the rs28936680 variant and a severe form of glaucoma. Glaucoma is a group of eye conditions that damage the optic nerve, often caused by abnormally high pressure in the eye. The CYP1B1 enzyme is known to be involved in the development of the eye, and mutations in the CYP1B1 gene are a common cause of primary congenital glaucoma (PCG), a severe, early-onset form of the disease. Individuals with specific genotypes at rs28936680, particularly those with two copies of the variant allele, are at a significantly increased risk for developing this condition, often from infancy or childhood. The inheritance pattern for this type of glaucoma is autosomal recessive, meaning both parents must carry at least one copy of the altered gene for a child to be affected.
Research Evidence and Diagnostic Considerations
The evidence linking rs28936680 to early-onset glaucoma is considered strong, particularly within certain populations. This variant has been identified as a founder mutation in some communities, suggesting it originated in a common ancestor and has been passed down through generations. While research clearly indicates a causal link between homozygous or compound heterozygous genotypes at rs28936680 and specific glaucoma phenotypes, the strength of evidence for milder or later-onset forms of glaucoma is less robust. It is crucial to understand that having one copy of the variant allele (a carrier state) typically does not cause glaucoma symptoms but may be relevant in genetic counseling. Clinical diagnosis of glaucoma requires a comprehensive eye examination by a qualified ophthalmologist, and genetic testing like that for rs28936680 serves as a supplementary tool, not a standalone diagnostic method.
What This Information Means for You
Knowledge of your genotype at rs28936680 can be informative, especially if you have a family history of early-onset glaucoma or belong to a population group with a higher prevalence of this variant. If you have two copies of the variant allele (a homozygous genotype), it indicates a significantly elevated risk for developing early-onset glaucoma, and regular, comprehensive eye screenings are highly recommended starting in infancy. If you have only one copy, you are a carrier, and while you are unlikely to develop glaucoma yourself due to this variant, you could pass the gene to your children. It is important to remember that genetic information is not a diagnosis. Decisions about genetic testing and interpretation should always be made in consultation with healthcare professionals, such as genetic counselors and ophthalmologists, who can provide personalized guidance and discuss potential screening or management strategies.
How common is this variant?
The gnomAD database indicates an approximate allele frequency of 0.0008 for rs28936680, with higher frequencies observed in Middle Eastern cohorts.
Frequently asked questions
What is rs28936680?
Rs28936680 is a specific genetic variation within the CYP1B1 gene. It is a missense mutation that has been strongly linked to a form of glaucoma that appears in infancy or childhood.
Does having rs28936680 mean I will definitely get glaucoma?
No, it does not guarantee you will get glaucoma. If you have one copy of the variant allele (A/G genotype), you are a carrier but unlikely to develop the condition yourself. If you have two copies (G/G genotype), your risk is significantly increased, and early and regular eye screenings are crucial.
Is rs28936680 more common in certain populations?
Yes, while the variant is found globally, its frequency is notably higher in populations of Middle Eastern ancestry. This suggests it may be a founder mutation in those communities.
Can rs28936680 be tested for?
Yes, genetic testing can identify your genotype at rs28936680. This information should be discussed with a healthcare professional or genetic counselor to understand its implications for your health and family.
What does CYP1B1 do in the body?
The CYP1B1 gene provides instructions for making an enzyme that is part of the cytochrome P450 family. This enzyme is involved in metabolizing various substances and plays a role in the development of the eye.
Sources & further reading
Educational information only, last refreshed 9/22/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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A well-characterized loss-of-function missense variant causing primary congenital glaucoma through abnormal trabecular meshwork development.
Missense variant in CYP1B1 associated with primary congenital glaucoma.
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