CYP19A1 rs121913058: Understanding Aromatase Deficiency Variants
The rs121913058 variant is a rare, pathogenic genetic change located within the CYP19A1 gene. It is associated with aromatase deficiency, a condition that disrupts the body's ability to convert androgens into estrogen, impacting reproductive development and bone health.
What each genotype means
Typical aromatase enzyme function
This genotype represents the most common genetic sequence for this location in the CYP19A1 gene. It is associated with normal production of the aromatase enzyme, which is responsible for converting androgens into estrogens. Individuals with this genotype do not carry the specific pathogenic variant associated with aromatase deficiency.
This is the most common genotype found in the general population worldwide.
Carrier of variant
This genotype indicates that you carry one copy of the rare variant and one copy of the typical sequence. Aromatase deficiency is an autosomal recessive condition, meaning that carrying a single copy typically does not result in the clinical symptoms of the deficiency. You may wish to consult with a genetic counselor if you have concerns about family planning or inherited conditions.
This genotype is extremely rare, consistent with the overall population frequency of the variant being less than 0.0001.
Potential aromatase deficiency
This genotype indicates that you carry two copies of the rare variant, which is associated with aromatase deficiency. This condition can lead to reduced aromatase activity, potentially causing symptoms such as virilization or issues with hormone regulation. Please discuss these results with a medical professional or endocrinologist to understand the clinical implications for your health.
This genotype is exceptionally rare and is not typically observed in the general population.
What is the rs121913058 Variant?
The rs121913058 variant is a specific change in the DNA sequence of the CYP19A1 gene. In genetics, a variant like this is often classified as a missense mutation, meaning it alters the genetic code in a way that changes the instructions for building a protein. This particular variant is categorized as pathogenic, which indicates that it is known to disrupt the normal function of the gene product. Because it is located within the coding region of the gene, it directly affects the structure of the aromatase enzyme. Understanding this variant requires looking at its position on chromosome 15, where the CYP19A1 gene resides. It is a rare finding in the general population, and its presence is typically investigated in clinical settings when individuals present with symptoms related to hormone imbalances or reproductive development issues.
The Role of the CYP19A1 Gene
The CYP19A1 gene provides the essential instructions for the body to produce an enzyme called aromatase. Aromatase plays a critical role in the endocrine system by converting androgens—often referred to as male sex hormones—into estrogens, which are female sex hormones. This conversion process is vital for both biological males and females, as it helps maintain the delicate balance of hormones required for normal reproductive development, bone density maintenance, and metabolic health. When the CYP19A1 gene is functioning correctly, aromatase ensures that the body has adequate levels of estrogen. If the gene contains a pathogenic variant that reduces or eliminates the enzyme's activity, the body may experience an accumulation of androgens and a deficiency in estrogen. This imbalance can lead to a variety of clinical features, ranging from atypical genital development at birth to issues with puberty and bone mineralization later in life.
Research and Clinical Associations
Scientific research has established a strong link between pathogenic variants in CYP19A1 and a condition known as aromatase deficiency. This is an autosomal recessive disorder, meaning that an individual typically needs to inherit two copies of a pathogenic variant—one from each parent—to manifest the clinical symptoms. Research studies have documented that individuals with this deficiency may experience virilization, which involves the development of masculine physical characteristics. In females, this can manifest as atypical external genitalia at birth and a lack of secondary sexual characteristics during puberty. In both sexes, the deficiency can lead to delayed bone age, reduced bone density, and metabolic challenges such as insulin resistance. The evidence for the pathogenicity of variants in this gene is well-supported by clinical case reports and molecular studies that demonstrate the loss of enzymatic activity. It is important to note that the severity of symptoms can vary depending on the specific nature of the genetic change and the degree of residual enzyme function.
Population Frequency and Interpretation
The rs121913058 variant is extremely rare in the global population, with a frequency reported in databases like gnomAD as less than 0.0001. Because it is so uncommon, it is not a variant that the general public would typically encounter in routine health screenings. Its rarity underscores that aromatase deficiency is a rare condition, often identified only through specialized genetic testing when clinical symptoms are present. For a reader, this information is primarily educational. If you or a family member have received a report mentioning this variant, it is essential to consult with a medical geneticist or a specialized endocrinologist. These professionals can provide context based on your specific clinical history and family background. Genetic information is complex, and a clinical expert is the only person qualified to interpret what a specific genotype means for an individual's health or to provide guidance on potential management strategies.
How common is this variant?
The rs121913058 variant is rare worldwide, with a frequency in the gnomAD database of less than 0.0001 across all major ancestral populations.
Frequently asked questions
What is aromatase deficiency?
Aromatase deficiency is a rare genetic condition where the body cannot produce enough aromatase enzyme. This leads to an imbalance of sex hormones, causing issues with reproductive development and bone health.
Is rs121913058 common?
No, this variant is extremely rare in the general population. It is not a common genetic marker found in most people.
Can I be tested for this variant?
Genetic testing for specific variants like rs121913058 is usually performed in a clinical setting by a doctor if there is a medical reason to suspect a genetic condition. You should discuss the necessity of such testing with a healthcare provider.
What should I do if I have this variant?
If you have concerns about a genetic report, the best course of action is to schedule an appointment with a genetic counselor or an endocrinologist. They can interpret the results in the context of your overall health.
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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This variant in the aromatase gene is associated with circulating estrogen levels and influences the timing of natural menopause and cardiovascular risk profiles in postmenopausal women.
This regulatory variant in the aromatase gene is associated with circulating estradiol levels and the timing of natural menopause.
Pathogenic variant causing aromatase deficiency characterized by female pseudohermaphroditism, maternal virilization during pregnancy, and absent pubertal development.
Intronic variant in the CYP19A1 gene associated with circulating estradiol and follicle-stimulating hormone (FSH) levels in men.
This variant in the aromatase gene is associated with variations in sex hormone levels and potential risk modulation for hormone-dependent reproductive cancers.
Affects aromatase activity, influencing efficacy and toxicity in hormone-sensitive cancer treatments.