SIX1 rs642742: Understanding Your Genetic Association
The rs642742 variant is a common genetic change located in an intergenic region near the SIX1 and SIX6 genes. Research has linked this specific site to variations in the vertical cup-to-disc ratio, a key structural measurement of the optic nerve often studied in the context of primary open-angle glaucoma susceptibility.
What each genotype means
Typical glaucoma risk profile
This genotype is associated with the SIX1-SIX6 locus, which has been linked to variations in the vertical cup-to-disc ratio and susceptibility to primary open-angle glaucoma. Research indicates that this region plays a role in ocular development, though the specific impact of this individual variant remains a subject of ongoing study. Please consult with an eye care professional for routine screenings, as this association does not constitute a medical diagnosis.
This genotype is common, appearing in a significant portion of the global population depending on ancestral background.
Typical glaucoma risk profile
This genotype is associated with the SIX1-SIX6 locus, which has been linked to variations in the vertical cup-to-disc ratio and susceptibility to primary open-angle glaucoma. Research indicates that this region plays a role in ocular development, though the specific impact of this individual variant remains a subject of ongoing study. Please consult with an eye care professional for routine screenings, as this association does not constitute a medical diagnosis.
This heterozygous genotype is frequently observed across diverse populations worldwide.
Typical glaucoma risk profile
This genotype is associated with the SIX1-SIX6 locus, which has been linked to variations in the vertical cup-to-disc ratio and susceptibility to primary open-angle glaucoma. Research indicates that this region plays a role in ocular development, though the specific impact of this individual variant remains a subject of ongoing study. Please consult with an eye care professional for routine screenings, as this association does not constitute a medical diagnosis.
This genotype is common, appearing in a significant portion of the global population depending on ancestral background.
What is rs642742?
The rs642742 variant is a single-nucleotide polymorphism (SNP), which is a variation at a single position in the DNA sequence. It is situated in an intergenic region—a stretch of DNA located between genes—on chromosome 14. Specifically, this variant sits in close proximity to the SIX1 and SIX6 genes. Because it is located in a non-coding region, scientists believe it may function as a regulatory element, potentially influencing how nearby genes are turned on or off. While it does not change the protein structure of SIX1 or SIX6 directly, its position suggests it could play a role in the complex genetic architecture that governs eye development and the maintenance of ocular structures.
The Role of the SIX1 Gene
The SIX1 gene encodes a homeobox protein, which acts as a transcription factor. Transcription factors are proteins that bind to specific DNA sequences to control the rate of gene expression. SIX1 is essential for the development of various tissues, including the limbs and the sensory organs. In the context of the eye, the SIX family of genes is known to be involved in the intricate processes that shape the optic nerve and the retina. Because the optic nerve head structure is a critical factor in glaucoma, researchers focus on genes like SIX1 to understand how developmental variations might influence an individual's long-term eye health and susceptibility to optic neuropathy.
Research and Evidence Strength
The association between the SIX1-SIX6 locus and eye-related traits is supported by several genome-wide association studies (GWAS). Specifically, rs642742 and neighboring variants have been linked to the vertical cup-to-disc ratio, which is a measurement of the optic nerve head's shape. A larger cup-to-disc ratio is often used by clinicians as a clinical marker for potential glaucoma risk. However, the evidence strength for this specific variant remains limited. While statistical associations are robust in large cohorts, the biological mechanism connecting this intergenic SNP to the actual development of primary open-angle glaucoma is still being investigated. It is important to note that genetic associations are not diagnostic; having a specific genotype does not mean an individual will develop a condition, nor does it guarantee protection.
Population Frequency
The rs642742 variant is considered common across diverse human populations. Data from large-scale genomic databases indicate that the minor allele frequency typically ranges between 30% and 50% worldwide. This high frequency suggests that the variant is an established part of human genetic diversity rather than a rare mutation. Because it is so common, it is found in individuals of many different ancestral backgrounds. The widespread nature of this variant underscores the importance of studying it across diverse cohorts to fully understand how its influence on ocular traits might vary depending on the broader genetic and environmental context of different populations.
What This Information Means for You
Understanding your genotype for rs642742 provides insight into your genetic predisposition regarding ocular structural traits, but it should not be used to predict health outcomes. Genetic associations are probabilistic, not deterministic. Many factors, including age, lifestyle, and other genetic variants, contribute to eye health. If you are concerned about glaucoma or changes in your vision, the most effective step is to schedule a comprehensive eye examination with an optometrist or ophthalmologist. They can perform clinical measurements, such as assessing your optic nerve head, which are far more predictive of your actual health status than any single genetic variant. Never use genetic information to make medical decisions or to alter any prescribed treatments without consulting your healthcare provider.
How common is this variant?
The rs642742 variant is common worldwide, with a minor allele frequency typically ranging from 30% to 50% across various ancestral populations.
Frequently asked questions
Does having the rs642742 variant mean I will get glaucoma?
No. This variant is associated with structural traits of the eye, such as the cup-to-disc ratio, but it is not a diagnostic test for glaucoma. Many people with this variant never develop the condition.
What is the vertical cup-to-disc ratio?
The vertical cup-to-disc ratio is a measurement used by eye doctors to describe the size of the 'cup' (the central depression) of the optic nerve relative to the entire 'disc' (the optic nerve head). Changes in this ratio can be a sign of optic nerve health.
Can I change my risk associated with this SNP?
You cannot change your DNA, but you can manage your eye health through regular comprehensive eye exams. Early detection of eye conditions by a professional is the best way to maintain vision.
Is this variant only found in certain ethnicities?
No, rs642742 is a common variant found across many different populations worldwide. It is not specific to any single ethnic or ancestral group.
Sources & further reading
Educational information only, last refreshed 9/28/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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