MYOC rs74315329: Understanding the Gln368Ter Variant
The rs74315329 variant, also known as Gln368Ter or Q368X, is a genetic change in the MYOC gene. It is recognized as a risk factor for primary open-angle glaucoma, a condition affecting the eye's drainage system.
What each genotype means
Typical MYOC profile
This is the most common genotype for this location in the MYOC gene. It is considered the reference sequence and is not associated with the increased risk of glaucoma linked to the Gln368STOP mutation.
This is the standard, most frequent genotype found in the vast majority of the global population.
Increased glaucoma risk
This genotype represents the Gln368STOP (p.Gln368Ter) mutation, which is a well-established risk factor for primary open-angle glaucoma. Research indicates that while this variant increases the risk of developing the condition, penetrance is incomplete, meaning not everyone with this genotype will develop glaucoma. You should discuss regular eye pressure monitoring and screening with an ophthalmologist.
This genotype is rare, carried by approximately 0.15% of individuals in European populations and is less common in other ancestral groups.
High glaucoma risk
This homozygous genotype is extremely rare and involves two copies of the Gln368STOP mutation. While clinical data on this specific homozygous state is limited, it is expected to carry a significant risk for early- or adult-onset primary open-angle glaucoma. Regular, proactive consultation with an eye care specialist is recommended to monitor intraocular pressure.
This genotype is exceptionally rare in the general population and is not typically observed in standard screening cohorts.
What is rs74315329?
The variant rs74315329 is a specific change in the DNA sequence of the MYOC gene, located on chromosome 1. In scientific literature, this is frequently referred to as the Gln368Ter or Q368X mutation. This notation indicates that a glutamine (Gln) amino acid at position 368 is replaced by a 'stop' codon (Ter). This premature stop signal can lead to the production of a truncated, or shortened, version of the myocilin protein. Because this change occurs within the coding region of the gene, it is classified as a nonsense variant. Researchers study this specific site because it is one of the most well-documented genetic markers associated with inherited forms of glaucoma, particularly in populations of European descent.
The Role of the MYOC Gene
The MYOC gene provides instructions for creating a protein called myocilin. This protein is primarily expressed in the trabecular meshwork, a tissue in the eye responsible for regulating the outflow of aqueous humor, the fluid that maintains eye pressure. When the MYOC gene functions normally, myocilin is secreted and helps maintain the structural integrity of the eye's drainage pathways. However, when mutations like rs74315329 occur, the resulting truncated protein may misfold. Research suggests that these misfolded proteins can accumulate within the cells of the trabecular meshwork, potentially triggering cellular stress or dysfunction. This disruption is thought to impair the eye's ability to drain fluid effectively, which can lead to increased intraocular pressure—a primary risk factor for the development of primary open-angle glaucoma.
Research and Evidence Strength
The association between the Gln368Ter variant and glaucoma is well-established in clinical research, though the penetrance—the likelihood that an individual with the variant will actually develop the disease—can vary. Studies have shown that this variant confers a higher risk for both juvenile-onset and adult-onset primary open-angle glaucoma. While the evidence linking this variant to glaucoma is strong, it is important to note that not everyone who carries this variant will develop the condition. The disease process is complex and likely involves interactions between the variant, other genetic factors, and environmental influences. Because of this, the variant is considered a significant risk factor rather than a definitive diagnostic marker. Clinical studies continue to investigate how this specific mutation influences the severity and progression of glaucoma in different individuals.
Population Frequency
The prevalence of the rs74315329 variant is not uniform across all human populations. It is most frequently observed in individuals of European ancestry, where the carrier frequency is approximately 0.15%. In contrast, the variant is considered rare or absent in many other ancestral groups. Because of this distribution, genetic screening for this specific variant is often prioritized in clinical contexts involving European populations with a family history of glaucoma. Understanding these frequency differences is crucial for researchers who study the global landscape of genetic risk factors. It highlights the importance of considering ancestral background when interpreting genetic test results, as the clinical relevance of a variant can depend heavily on the population in which it is being studied.
Managing Genetic Information
If you have received information about your status regarding the rs74315329 variant, it is important to understand what this means for your health. This information is not a medical diagnosis and cannot predict with certainty whether you will develop glaucoma. Genetic variants are only one piece of a much larger puzzle that includes your overall health, family history, and lifestyle. If you are concerned about your eye health or have a family history of glaucoma, the most appropriate step is to consult with an ophthalmologist or a genetic counselor. They can provide a comprehensive eye examination and discuss whether further testing or monitoring is necessary based on your specific clinical profile. Never make changes to your healthcare or medical management based solely on genetic data without professional guidance.
How common is this variant?
The rs74315329 variant has a carrier frequency of approximately 0.15% in European populations and is considered rare in other ancestral groups.
Frequently asked questions
Does having the rs74315329 variant mean I will get glaucoma?
No, having this variant does not guarantee that you will develop glaucoma. It is a risk factor, but other genetic and environmental factors also play a significant role in the development of the disease.
What should I do if I have the rs74315329 variant?
If you are aware that you carry this variant, you should discuss it with an eye care professional, such as an ophthalmologist. They can perform regular screenings to monitor your eye pressure and optic nerve health.
Is rs74315329 the same as Gln368Ter?
Yes, rs74315329 is the unique identifier (rsID) used in scientific databases for the Gln368Ter mutation in the MYOC gene. They refer to the exact same genetic change.
Can I be tested for this variant?
Genetic testing for specific variants is available through clinical laboratories, usually ordered by a physician or genetic counselor. You should discuss the necessity and implications of such testing with your healthcare provider.
Sources & further reading
Educational information only, last refreshed 9/20/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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Encodes the classical Gln368STOP mutation in myocilin, a well-validated genetic cause of juvenile- and adult-onset primary open-angle glaucoma.
A major missense variant in the myocilin olfactomedin domain causative of juvenile- and adult-onset primary open-angle glaucoma.
Missense mutation in MYOC (p.Gln368Glu) predisposing carriers to elevated intraocular pressure and adult-onset primary open-angle glaucoma.
A pathogenic point mutation in MYOC strongly linked to autosomal dominant primary open-angle glaucoma with high intraocular pressure.
A pathogenic missense variant in myocilin causing trabecular meshwork disruption and juvenile-onset open-angle glaucoma.
A pathogenic missense variant (p.Gln368Ter) in the MYOC gene, a major genetic risk factor for primary open-angle glaucoma.