FSHB rs10835638: What Your Genotype Means
The rs10835638 variant is a single nucleotide polymorphism located in the promoter region of the FSHB gene. It is statistically associated with variations in circulating follicle-stimulating hormone (FSH) levels and the timing of reproductive milestones like menopause.
What each genotype means
Typical FSH production
This is the most common genotype for this variant. Research indicates that individuals with this genotype typically exhibit standard levels of FSHB transcription and circulating follicle-stimulating hormone (FSH) compared to those carrying the T allele.
Carried by approximately 73% of individuals in studied cohorts, though frequencies vary by ancestry.
Reduced FSH production
Carrying one copy of the T allele is associated with reduced FSHB promoter activity and lower circulating FSH levels. Research suggests this may influence reproductive traits, such as menstrual cycle length or fertility, though these associations are complex and can vary significantly between individuals.
Carried by roughly 24% of individuals in studied cohorts.
Lower FSH production
This genotype is associated with the lowest levels of FSHB transcription and circulating FSH among the three genotypes. Studies have linked this profile to altered reproductive hormone levels, including lower FSH-to-LH ratios in men and longer menstrual cycles in women; please discuss any concerns regarding reproductive health or hormone levels with your clinician.
Carried by approximately 3% of individuals in studied cohorts.
Understanding the rs10835638 Variant
The rs10835638 variant is a specific genetic change located within the promoter region of the FSHB gene. In genetics, a promoter is a regulatory sequence of DNA that acts as an on-off switch for a gene, determining how much of a protein is produced. This particular SNP involves a substitution where a guanine (G) is replaced by a thymine (T). Because this change occurs in a regulatory area, researchers have investigated whether it influences the efficiency with which the body transcribes the FSHB gene. By sitting in this critical control region, the variant may subtly alter the expression levels of the hormone it encodes, potentially impacting physiological processes that rely on precise hormonal signaling. It is a well-studied marker in reproductive genetics, often analyzed to understand the biological variability in hormone profiles across different individuals.
The Role of the FSHB Gene
The FSHB gene provides the instructions for creating the beta subunit of follicle-stimulating hormone (FSH). FSH is a vital glycoprotein hormone produced by the pituitary gland that plays a central role in human reproduction. In females, it is essential for the development and maturation of ovarian follicles, which contain eggs, and it helps regulate the menstrual cycle. In males, FSH is critical for spermatogenesis, the process by which the testes produce sperm. Because FSHB is the rate-limiting component of the hormone, the regulation of its transcription is tightly controlled by signals from the hypothalamus and other feedback loops. Any variation that affects the promoter region of this gene can theoretically influence the total amount of FSH circulating in the bloodstream, which in turn may affect the sensitivity and function of the reproductive system.
Research and Associations
Scientific research has identified significant associations between the rs10835638 variant and various reproductive traits. Studies have shown that the T allele is associated with lower circulating levels of FSH in both men and women. In women, this reduction in FSH has been linked to longer menstrual cycles and a slightly later age at natural menopause. While these associations are statistically significant, the evidence strength is considered moderate, as the biological impact of the variant is often subtle and influenced by a complex interplay of other genetic and environmental factors. Some research has also explored its potential role in conditions like polycystic ovary syndrome (PCOS) or ovarian response to stimulation, though findings remain mixed. It is important to note that these associations describe population-level trends rather than individual clinical outcomes, and the variant does not act as a standalone predictor of fertility or reproductive health.
Interpreting Your Genetic Information
When reviewing information about rs10835638, it is essential to understand that genetic associations are not diagnostic. Having a specific genotype does not mean an individual will experience a specific reproductive outcome, as many factors—including age, lifestyle, and other genetic markers—contribute to hormonal health. This information is intended for educational purposes to help you understand the biological variability that exists within human populations. If you have concerns about your reproductive health, hormone levels, or fertility, you should consult with a qualified healthcare provider or a reproductive endocrinologist. They can provide personalized testing and clinical evaluations that are far more informative than a single SNP result. Never use genetic data to make medical decisions or alter treatments without professional guidance, as your clinician is the only one who can interpret these findings in the context of your overall health history.
How common is this variant?
The G allele is the most common, with frequencies reported around 87-88%, while the T allele is less common, appearing at a frequency of approximately 12-13% in studied populations.
Frequently asked questions
Does the rs10835638 variant cause infertility?
No, this variant is not a cause of infertility. It is a common genetic marker associated with subtle differences in hormone levels and reproductive timing, not a clinical diagnosis of infertility.
Can I use this SNP to predict when I will reach menopause?
While research shows an association between this variant and the age of menopause, it is not a precise tool for prediction. Many factors, including genetics, environment, and health history, determine the timing of menopause.
Should I get my FSH levels tested because of this variant?
You should only get your hormone levels tested if recommended by your doctor. Genetic variants alone do not dictate your current hormonal status, and clinical testing is the only way to assess your actual hormone levels.
Is this variant related to PCOS?
Some studies have investigated the link between this variant and polycystic ovary syndrome (PCOS). However, the evidence is not definitive, and PCOS is a complex condition influenced by many different genetic and environmental factors.
Sources & further reading
Educational information only, last refreshed 10/6/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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This missense variant in the FSHB gene is associated with spermatogenic impairment and abnormal sperm counts.
Promoter-adjacent variant linked to FSHB expression, influencing basal follicle-stimulating hormone levels, menstrual cycle duration, and twinning propensity.
Pathogenic loss-of-function variant causing isolated follicle-stimulating hormone deficiency leading to hypogonadotropic hypogonadism.
Functional promoter variant in FSHB influencing serum FSH concentrations and reproductive lifespan.
Variant in the promoter region of FSHB associated with circulating follicle-stimulating hormone levels, age at menarche, and reproductive lifespan.
Variant in the promoter region of FSHB associated with altered follicle-stimulating hormone levels, timing of menarche, and female reproductive lifespan.