FSHB rs10835637: What Your Genotype Means
The rs10835637 single-nucleotide polymorphism is a regulatory variant located in the promoter region of the FSHB gene. Closely linked to the widely studied c.-211G>T variant, it influences the transcriptional activity of follicle-stimulating hormone (FSH). Population research associates this locus with differences in circulating FSH levels, timing of menopause and menarche, menstrual cycle length, and natural twinning rates.
What each genotype means
Typical FSH baseline expression
You carry two copies of the common G allele at the FSHB promoter site (c.-211G>T). Research associates this genotype with typical transcriptional activity of follicle-stimulating hormone, standard average menstrual cycle lengths, and baseline population rates of dizygotic twinning and timing of reproductive milestones. In men, this genotype is typically correlated with normal baseline serum FSH concentrations and standard reproductive parameters.
Carried by approximately 70% to 75% of individuals of European ancestry and over 80% of individuals of East Asian ancestry.
Moderately reduced FSH expression
You carry one copy of the T regulatory allele at the FSHB promoter site (c.-211G>T). Studies associate this genotype with modestly reduced FSHB promoter activity, resulting in slightly lower circulating FSH levels, slightly longer menstrual cycle lengths (roughly one additional day on average), and subtly later onset of natural menopause. Research also notes minor reductions in the likelihood of spontaneous dizygotic twinning and small shifts in male gonadotropin and sperm parameters.
Carried by approximately 24% to 26% of individuals of European ancestry and roughly 15% of individuals of East Asian descent.
Reduced FSH transcriptional activity
You carry two copies of the T regulatory allele at the FSHB promoter site (c.-211G>T). Published studies link this genotype to a substantial reduction in FSHB transcriptional activity in vitro and noticeably lower circulating baseline FSH levels. In population research, this is correlated with longer menstrual cycles, later natural menopause timing, lower spontaneous twin rates, and in some cohorts, reduced sperm parameters or mild secondary functional hypogonadism in men.
Carried by approximately 2% to 3% of individuals of European ancestry and less than 1% of East Asian populations.
What Is rs10835637 and Where Is It Located?
The single-nucleotide polymorphism rs10835637 is a genetic variant situated on chromosome 11 within the regulatory promoter region upstream of the FSHB gene. In human reproductive genetics literature, this genomic locus is often discussed alongside or interchangeably with the classic promoter variant c.-211G>T (rs10835638), with which it shares strong linkage disequilibrium. Regulatory variants in this region alter binding motifs for nuclear transcription factors, modifying how efficiently the promoter initiates transcription. Rather than changing the amino acid sequence of a protein, non-coding promoter variants like rs10835637 act like a biological dimmer switch, tuning baseline gene expression up or down across an individual's lifetime.
The Biological Function of the FSHB Gene
The FSHB gene encodes the beta-subunit of follicle-stimulating hormone (FSH), a vital glycoprotein gonadotropin produced by the anterior pituitary gland. FSH functions as a heterodimer composed of a common alpha subunit and the hormone-specific beta subunit encoded by FSHB. In females, FSH stimulates the maturation of ovarian follicles and regulates estrogen synthesis during the follicular phase of the menstrual cycle. In males, FSH acts on testicular Sertoli cells to initiate and support normal spermatogenesis. Because synthesis of the beta-subunit serves as the rate-limiting step in mature FSH production, genetic variations in the FSHB promoter have a direct impact on circulating concentrations of active gonadotropins.
Published Associations and Evidence Strength
Genome-wide association studies and large cohorts such as the UK Biobank have linked variants in the FSHB promoter to broad reproductive traits. The alternate T-allele is consistently correlated with lower circulating serum FSH concentrations in both sexes. Because lower FSH reduces the rate of ovarian follicular recruitment, carrying the minor allele has been statistically associated with longer menstrual cycles, modest delays in natural menopause, and reduced rates of dizygotic (fraternal) twinning. Conversely, higher baseline FSH driven by the reference G-allele has been linked to increased risk of conditions like endometriosis. However, the evidence strength for direct individual risk predictions remains limited because reproductive outcomes are highly polygenic and heavily influenced by age, lifestyle, and other hormonal axes.
What You Can and Cannot Do with This Information
Genotype data for rs10835637 provides educational context regarding baseline biological tendencies rather than definitive clinical forecasts. Having a genotype linked to lower or higher FSH does not diagnose infertility, polycystic ovary syndrome, or premature ovarian insufficiency, nor does it guarantee a specific age of menopause. Reproductive health relies on an intricate feedback loop involving luteinizing hormone, estradiol, progesterone, and environmental exposures. This variant should never be used on its own to make family planning choices, select hormone replacement dosages, or guide fertility treatments. Any clinical decisions regarding reproductive planning or hormone therapies must be made in collaboration with a licensed healthcare provider.
How common is this variant?
The minor T allele frequency is approximately 0.15 in populations of European ancestry and roughly 0.08 in East Asian populations, with lower frequencies observed in African ancestries.
Frequently asked questions
Does carrying the rs10835637 T allele cause female infertility?
No, carrying the T allele is not a direct cause of infertility. While large studies observe a slight statistical association with nulliparity and longer menstrual cycles due to lower average FSH, most individuals carrying this allele reproduce naturally without clinical difficulties.
Can this genetic variant predict my exact age at menopause?
No, rs10835637 cannot predict your exact age at menopause. Although research links the FSH-lowering allele to a modest statistical delay in natural menopause of a few months, menopause timing is governed by hundreds of genetic loci alongside environmental factors.
How does rs10835637 relate to natural twinning rates?
Follicle-stimulating hormone drives multiple follicular development during ovulation. The reference G allele promotes higher baseline FSH, which increases the likelihood of releasing multiple eggs in a cycle, whereas the FSH-lowering T allele is associated with lower odds of natural fraternal twins.
Does rs10835637 have any effect in men?
Yes, because FSH regulates Sertoli cell function in the testes, men carrying the T allele tend to have lower serum FSH levels. Some studies suggest this may lead to subtle differences in testicular volume and sperm concentration, although reproductive capability typically remains within normal ranges.
Sources & further reading
Educational information only, last refreshed 9/12/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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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.
Located in the promoter of FSHB (c.-211G>T), this variant downregulates follicle-stimulating hormone transcription and is strongly associated with male infertility traits (oligozoospermia) and altered female reproductive lifespan.
Variant in the promoter region of FSHB associated with altered follicle-stimulating hormone levels, timing of menarche, and female reproductive lifespan.