CYP21A2 rs74315355: Understanding Your Genetic Variant
The rs74315355 variant is located within the CYP21A2 gene, which provides instructions for the 21-hydroxylase enzyme. This specific genetic change is associated with non-classic congenital adrenal hyperplasia, a condition that can influence hormone production and reproductive health.
What each genotype means
Typical enzyme activity
This genotype represents the most common sequence found in the general population for this specific location in the CYP21A2 gene. It is not associated with the pathogenic changes linked to non-classic congenital adrenal hyperplasia. Individuals with this profile are not expected to have altered 21-hydroxylase enzyme function related to this specific variant.
This is the most common genotype observed across all major global populations.
Carrier of variant
This genotype indicates that you carry one copy of the variant allele, which is associated with non-classic congenital adrenal hyperplasia. Because this condition is typically inherited in an autosomal recessive manner, carrying a single copy generally does not result in clinical symptoms, though you may be a carrier who could pass the variant to offspring. Please consult with a genetic counselor or physician to discuss what this means for your personal health and family planning.
The variant allele has a minor allele frequency of approximately 0.015 in Ashkenazi Jewish populations, making this heterozygous genotype relatively uncommon.
Potential reduced enzyme activity
This genotype indicates that you carry two copies of the variant allele, which has been associated with non-classic congenital adrenal hyperplasia. This condition can present with symptoms such as hyperandrogenism, oligomenorrhea, and subfertility due to mild deficiency of the 21-hydroxylase enzyme. You should discuss these findings with an endocrinologist or healthcare provider to determine if any clinical evaluation is appropriate for your specific health context.
This homozygous genotype is rare in the general population and is most frequently studied in specific ethnic groups where the variant is more prevalent.
What is the rs74315355 Variant?
The rs74315355 variant is a specific change in the DNA sequence of the CYP21A2 gene. In genetics, a single nucleotide polymorphism (SNP) like this represents a variation at a single position in the genome. The CYP21A2 gene is located on the long arm of chromosome 6, situated within a complex region known as the human leukocyte antigen (HLA) locus. This area of the genome is highly variable and plays a critical role in immune system function, which makes the study of variants in this region particularly complex. When a variant occurs in the CYP21A2 gene, it can potentially alter the structure or function of the protein it encodes, which may have downstream effects on the body's hormonal balance.
The Role of the CYP21A2 Gene
The CYP21A2 gene is responsible for producing an enzyme called 21-hydroxylase. This enzyme is essential for the adrenal glands to function correctly, as it helps convert cholesterol into vital steroid hormones, including cortisol and aldosterone. Cortisol is necessary for managing stress and maintaining blood sugar levels, while aldosterone helps regulate blood pressure and salt balance in the body. When the 21-hydroxylase enzyme is deficient or inactive due to genetic variants, the adrenal glands may struggle to produce these hormones in sufficient quantities. This disruption can lead to an overproduction of androgens, which are male-type hormones that can cause various physical symptoms in both males and females, such as irregular menstrual cycles or signs of hyperandrogenism.
Research and Clinical Associations
Research associates the rs74315355 variant with non-classic congenital adrenal hyperplasia (NCAH). Unlike the classic form of the condition, which is typically diagnosed in infancy due to severe hormone deficiency, the non-classic form often presents later in life. Clinical observations suggest that individuals with this variant may experience symptoms like oligomenorrhea (infrequent menstrual periods), subfertility, and signs of excess androgens. However, the evidence strength for this specific variant is currently categorized as limited. It is important to note that the presence of a genetic variant does not guarantee the development of a clinical condition. Many factors, including other genetic modifiers and environmental influences, contribute to how a person's health is expressed. Genetic testing is often used as a complement to biochemical hormone testing to help clinicians understand the underlying cause of symptoms.
Population Frequency
The frequency of genetic variants can vary significantly across different ancestral groups. For the rs74315355 variant, current data indicates a minor allele frequency (MAF) of approximately 0.015 in Ashkenazi Jewish populations. This means that the variant is relatively uncommon but present within this specific demographic. Because genetic variants are often distributed unevenly across global populations, researchers look at these frequencies to better understand the history and prevalence of certain traits or conditions. If you are interested in your own genetic profile, it is helpful to discuss these findings with a genetic counselor who can provide context based on your specific background and family history.
Managing Your Genetic Information
If you have received information about your status for the rs74315355 variant, it is important to understand what you can and cannot do with this data. This information is not a medical diagnosis and should not be used to make decisions about your health without professional guidance. If you are experiencing symptoms related to hormone imbalances, such as menstrual irregularities or fertility concerns, consult a healthcare provider or an endocrinologist. They can perform the necessary blood tests to measure hormone levels and determine if any treatment is appropriate. Never start, stop, or change any medication based on genetic test results alone. Always discuss your results with a qualified clinician or pharmacist who can interpret the findings in the context of your overall health and medical history.
How common is this variant?
The rs74315355 variant has a minor allele frequency of approximately 0.015 in Ashkenazi Jewish populations.
Frequently asked questions
Is rs74315355 a diagnosis for CAH?
No, identifying a genetic variant is not a medical diagnosis. A diagnosis of congenital adrenal hyperplasia requires clinical evaluation and biochemical testing by a medical professional.
What should I do if I have this variant?
If you are concerned about your health, consult an endocrinologist or a genetic counselor. They can help you understand your results and determine if any further testing is necessary.
Can this variant affect my fertility?
The variant is associated with non-classic congenital adrenal hyperplasia, which can sometimes cause menstrual irregularities or subfertility. However, many individuals with genetic variants do not experience these issues.
Where can I find more information on CYP21A2?
You can visit resources like MedlinePlus Genetics or the NCBI Gene database for comprehensive information on the CYP21A2 gene and its role in human health.
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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Pathogenic variant (p.Val282Leu) in CYP21A2 associated with non-classic congenital adrenal hyperplasia.
Pathogenic variant in CYP21A2 associated with 21-hydroxylase deficiency, used in reproductive carrier screening.
Pathogenic missense variant in CYP21A2 associated with 21-hydroxylase deficiency, a cause of congenital adrenal hyperplasia.
Well-characterized pathogenic missense variant (p.Pro30Leu) causing non-classic congenital adrenal hyperplasia and female hyperandrogenic subfertility.
This variant in the CYP21A2 gene is involved in steroid hormone metabolism and is noted in clinical databases.
This variant is classified as pathogenic and is associated with 21-hydroxylase deficiency.