CYP19A1 rs2414098: Estrogen Regulation and PCOS Risk
The genetic variant rs2414098 is a single nucleotide polymorphism located within an intronic region of the CYP19A1 gene on chromosome 15. The CYP19A1 gene encodes aromatase, the key enzyme that converts androgen precursors into active estrogens such as estradiol and estrone. Published research suggests that rs2414098 is associated with subtle differences in circulating estrogen levels, follicular maturation dynamics, and susceptibility to polycystic ovary syndrome (PCOS), though the overall clinical evidence remains limited and modest in effect size.
What each genotype means
Typical aromatase activity profile
Individuals with this genotype carry the major allele. Research in large-scale studies, including the UK Biobank, has observed that carriers of this genotype do not show the reduction in estrone levels or the associated decrease in endometrial cancer risk that is linked to the alternative T allele. This is considered a baseline or common genotype in most studied populations.
Carried by the majority of the population globally, with frequencies varying by ancestry.
Potentially altered estrogen influence
This heterozygous genotype is associated with a moderate, dose-dependent influence on hormone regulation compared to CC homozygotes. Scientific studies have identified the T allele as an effect allele linked to lower circulating estrone concentrations and a statistically significant reduction in the risk of endometrial cancer. Because this association is based on statistical trends in populations, it does not allow for individual clinical prediction.
This genotype is common, occurring in a significant portion of individuals across diverse ancestries.
Associated with lower estrone levels
Individuals with this genotype carry two copies of the T allele. Population-level research indicates this genotype is associated with lower circulating estrone concentrations and, consequently, a reduced statistical likelihood of developing endometrial cancer. This association is observed across older female cohorts, though individual risk remains influenced by many other genetic and lifestyle factors.
This is the less common genotype; its frequency varies significantly by ancestral background.
Genomic Location and Variant Characteristics
The single nucleotide polymorphism rs2414098 is situated on chromosome 15 (cytogenetic band 15q21.2) within the non-coding intronic architecture of the CYP19A1 gene. At this position, genomic databases document a single-base transition involving cytosine (C) and thymine (T) alleles. Because rs2414098 resides in an intron rather than a protein-coding exon, it does not directly alter the amino acid sequence of the resulting enzyme. Instead, researchers classify it as a regulatory or tagging variant that may modulate gene transcription, influence alternative splicing pathways, or track in linkage disequilibrium with other functionally active non-coding loci in the CYP19A1 locus. Intronic polymorphisms in this genomic region have attracted attention across reproductive genetics because regulatory variants can modify tissue-specific expression of steroidogenic enzymes without abolishing essential catalytic activity.
The Biological Role of CYP19A1 and Aromatase
The CYP19A1 gene encodes aromatase cytochrome P450, a rate-limiting enzyme in human steroidogenesis. Located primarily in the endoplasmic reticulum of ovarian granulosa cells, adipose tissue, placenta, and brain tissue, aromatase catalyzes the final three steps in estrogen biosynthesis. Specifically, it converts the androgenic precursors androstenedione and testosterone into the primary estrogens, estrone and 17β-estradiol, respectively. In females of reproductive age, ovarian granulosa cell aromatase activity is tightly driven by follicle-stimulating hormone (FSH) and plays an indispensable role in follicular growth, oocyte maturation, and regular ovulatory signaling. Because estrogen balance coordinates the delicate feedback loops connecting the ovaries, pituitary gland, and hypothalamus, even subtle, genetically driven shifts in aromatase expression can theoretically influence downstream hormone concentrations, the local microenvironment of growing follicles, and broader reproductive physiology.
Research Associations with Estradiol, Folliculogenesis, and PCOS
Population-based genetic studies and genome-wide association studies (GWAS) have evaluated rs2414098 in connection with circulating estrogen levels, reproductive traits, and hormone-dependent conditions. The cataloged associations indicate that variation at this locus correlates with modest differences in circulating estradiol and estrone concentrations. In female reproductive medicine, aromatase activity is directly linked to follicular maturation and the development of polycystic ovary syndrome (PCOS). In PCOS pathophysiology, impaired aromatization of androgens into estrogens can contribute to relative hyperandrogenism and anovulatory cycles. However, the evidence connecting rs2414098 to PCOS susceptibility is graded as limited: findings are mixed across distinct ethnic cohorts, single-variant effect sizes are small, and rs2414098 does not function as an independent, deterministic risk factor. Rather, it appears to act as a minor modifier within a deeply polygenic landscape shaped heavily by metabolic, hormonal, and environmental contributors.
Allele and Genotype Distribution Across Populations
According to population genomics datasets, including the Genome Aggregation Database (gnomAD), the minor allele frequency of rs2414098 varies across global ancestries, with an overall global minor allele frequency estimated around 0.15 (15%). The major allele across most studied populations is cytosine (C), making the homozygous CC genotype the most frequently encountered pairing, present in an estimated 70% to 75% of individuals worldwide. The heterozygous CT genotype occurs in approximately 25% of individuals, while the homozygous minor TT genotype represents a small minority, generally observed in fewer than 3% to 5% of individuals globally. Because allele distributions fluctuate between European, East Asian, South Asian, African, and admixed populations, association studies must be interpreted strictly within ancestral contexts, as linkage patterns and baseline hormone references often differ significantly between groups.
Translating Genetic Data into Perspective
Carrying an associated allele at rs2414098 does not provide a diagnosis, predict future fertility, or guarantee the onset of polycystic ovary syndrome or estrogen-related disorders. In reproductive endocrinology, complex conditions like PCOS are diagnosed through validated clinical criteria—such as chronic anovulation, clinical or biochemical hyperandrogenism, and polycystic ovarian morphology detected on ultrasound—rather than common single nucleotide polymorphisms. Consumers should view rs2414098 data as educational context highlighting how steroidogenesis genes exhibit natural human diversity. Any concerns regarding irregular menstrual cycles, unexplained androgenic symptoms, fertility assessments, or hormonal therapies should always be brought to a board-certified clinician or reproductive endocrinologist. If you are taking hormone-altering medications or aromatase inhibitors, dosing and management should exclusively be evaluated in partnership with your prescribing physician or pharmacist.
How common is this variant?
The minor allele of rs2414098 has a global frequency of approximately 0.15 in gnomAD, with the homozygous major genotype (CC) being the most prevalent across global ancestries and the homozygous minor genotype (TT) occurring in fewer than 5% of individuals.
Frequently asked questions
Can testing rs2414098 tell me if I have PCOS?
No, testing rs2414098 cannot diagnose polycystic ovary syndrome. PCOS is a complex multifactorial condition diagnosed by physicians using formal diagnostic criteria, including ultrasound evaluations, symptom history, and laboratory blood tests. Single common genetic variants like rs2414098 have very small statistical effects and lack the sensitivity or specificity required for clinical screening.
How does the CYP19A1 gene affect estrogen levels?
The CYP19A1 gene provides the biological instructions for making aromatase, the primary enzyme responsible for converting androgens into estrogens. Variations in the CYP19A1 gene can subtly influence how much aromatase is expressed in tissues such as the ovaries and adipose tissue. This can lead to small, measurable differences in circulating estradiol and estrone concentrations across different people.
Does rs2414098 affect male hormones or testosterone levels?
Because aromatase actively converts testosterone into estradiol in both men and women, variants in CYP19A1 can theoretically influence the androgen-to-estrogen balance across sexes. However, research on rs2414098 has primarily focused on female reproductive health and postmenopausal hormone cohorts. Any functional influence on male androgen levels remains modest and requires further clinical validation.
Should I change any medications if I carry the minor allele?
No, you should never alter any medication, hormone therapy, or aromatase inhibitor regimen based on consumer genetic results for rs2414098. This variant is not included in clinical pharmacogenomic dosing guidelines, and individual medical treatments must be based on comprehensive clinical evaluation. Any medication questions should be addressed directly with your doctor or pharmacist.
Sources & further reading
Educational information only, last refreshed 9/7/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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Intronic variant in the CYP19A1 gene associated with circulating estradiol and follicle-stimulating hormone (FSH) levels in men.
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