MYOC rs74315353: Understanding This Juvenile Glaucoma Variant
The rs74315353 variant is a rare, pathogenic genetic change located in the MYOC gene. It is specifically associated with an increased risk of developing aggressive, juvenile-onset open-angle glaucoma.
What each genotype means
Typical MYOC profile
This genotype represents the common, non-pathogenic sequence for this specific location in the MYOC gene. It is not associated with the increased risk of juvenile-onset open-angle glaucoma linked to the p.Pro370Leu variant.
This is the most common genotype found in the general population across all ancestries.
Increased glaucoma risk
This genotype includes the p.Pro370Leu missense variant, which is a known pathogenic mutation in the MYOC gene. Research indicates this variant is associated with an autosomal dominant pattern of inheritance and high penetrance for aggressive, juvenile-onset open-angle glaucoma. Individuals with this genotype should consult with an ophthalmologist for regular monitoring of intraocular pressure.
This specific variant is extremely rare, with a global minor allele frequency reported at less than 0.00005 in large population databases.
High risk profile
This genotype indicates the presence of two copies of the p.Pro370Leu variant. While the condition is typically inherited in an autosomal dominant manner, the presence of this variant is strongly linked to the development of juvenile-onset open-angle glaucoma. Clinical evaluation and long-term management by an eye care specialist are recommended for individuals identified with this variant.
This homozygous genotype is exceptionally rare and has not been widely characterized in general population studies.
What is the rs74315353 Variant?
The rs74315353 variant is a specific change in the DNA sequence of the MYOC gene, which stands for myocilin. In genetic terms, this is a missense mutation, meaning it causes a single amino acid substitution—specifically, proline to leucine at position 370 (p.Pro370Leu)—within the protein's structure. This variant is located in the olfactomedin domain, a critical region of the myocilin protein. Because this change occurs in a functional part of the protein, it is classified as a pathogenic variant. It is primarily studied in the context of inherited eye conditions, particularly those that manifest early in life. Geneticists track this variant to understand how specific structural changes in proteins can lead to complex physiological outcomes in the human eye.
The Role of the MYOC Gene
The MYOC gene provides the instructions for building the myocilin protein. This protein is found in high concentrations within the trabecular meshwork and the ciliary body of the eye. These structures are essential for regulating intraocular pressure, which is the fluid pressure inside the eye. Under normal conditions, myocilin is thought to interact with other proteins in the extracellular matrix to provide structural support and maintain proper fluid drainage. When the MYOC gene contains a pathogenic variant, the resulting myocilin protein may misfold. Instead of being secreted into the extracellular matrix, this defective protein can accumulate inside the cell. This accumulation is believed to cause cellular stress or damage, which impairs the eye's ability to drain fluid effectively, leading to a dangerous increase in intraocular pressure.
Research and Evidence Strength
Research into MYOC variants has been ongoing for over two decades. The association between specific MYOC mutations and juvenile-onset open-angle glaucoma (JOAG) is well-documented in clinical literature. Studies have shown that these variants can account for a significant portion of JOAG cases, sometimes ranging from 4% to 30% depending on the population studied. The evidence for rs74315353 specifically points to a high-penetrance, pathogenic mechanism. This means that individuals who carry this variant are at a substantially higher risk of developing the condition compared to the general population. While the link between MYOC mutations and glaucoma is strong, it is important to note that glaucoma is a multifactorial disease. Other genetic and environmental factors also play a role in the development and progression of the condition, and not every individual with a MYOC variant will experience the same clinical severity.
Population Frequency
The rs74315353 variant is extremely rare in the general population. According to large-scale genomic databases like gnomAD, the global minor allele frequency is less than 0.00005. Because it is so rare, it is not typically found in the general screening of healthy individuals. Instead, this variant is most often identified through targeted genetic testing in families that have a documented history of early-onset or juvenile glaucoma. Its rarity underscores that it is not a common risk factor for the general population but rather a specific, high-impact mutation that segregates within certain affected pedigrees. Because of its low frequency, researchers rely heavily on clinical case studies and family-based linkage analyses to understand its impact, rather than large-scale population-wide association studies.
What This Information Means for You
If you or a family member have been identified as a carrier of the rs74315353 variant, it is important to understand that this is a clinical finding that requires professional medical interpretation. This information is not a diagnosis of glaucoma, but it does indicate a genetic predisposition that warrants regular, specialized eye examinations. Because this variant is associated with juvenile-onset glaucoma, early and consistent monitoring of intraocular pressure by an ophthalmologist is often recommended. You cannot change your genetic sequence, but understanding your risk profile allows for proactive health management. Always discuss genetic test results with a qualified genetic counselor or an eye specialist who can provide context based on your personal and family medical history. Do not make changes to your healthcare or monitoring schedule without consulting your medical provider.
How common is this variant?
The rs74315353 variant is extremely rare, with a global minor allele frequency of less than 0.00005 in the gnomAD database.
Frequently asked questions
Is rs74315353 a diagnosis for glaucoma?
No, identifying this variant is not a diagnosis. It is a genetic finding that indicates an increased risk, and you should consult an ophthalmologist for a clinical evaluation.
What is the difference between POAG and JOAG?
POAG (Primary Open-Angle Glaucoma) is the most common adult form, while JOAG (Juvenile-Onset Open-Angle Glaucoma) is a rarer, early-onset form typically diagnosed before age 40.
Can I prevent glaucoma if I have this variant?
While you cannot change your genetics, early detection through regular eye exams can help manage intraocular pressure and potentially slow the progression of the disease.
Should I get tested for MYOC variants?
Genetic testing for MYOC is usually recommended by specialists for individuals with a strong family history of early-onset glaucoma. Discuss the necessity of testing with a genetic counselor.
Sources & further reading
Educational information only, last refreshed 9/18/2026. 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.
Known as the Gln368STOP mutation in MYOC, this nonsense variant is a well-established cause of autosomal dominant juvenile- and adult-onset primary open-angle glaucoma.