FSHB rs11031005: Hormones and Reproductive Timing
The rs11031005 single nucleotide polymorphism is an upstream promoter variant near the FSHB gene, which encodes the beta subunit of follicle-stimulating hormone. Large-scale population genomics studies link this regulatory variant to circulating gonadotropin levels, female reproductive milestones such as age at menarche and menopause, and risk for polycystic ovary syndrome (PCOS). Because it operates as a modest regulatory factor rather than a deterministic switch, it provides insight into subtle hormonal variation rather than definitive health outcomes.
What each genotype means
Typical FSHB promoter activity
This genotype represents the most common form of the FSHB promoter region. Research indicates this version is associated with standard baseline levels of follicle-stimulating hormone (FSH) and typical timing for reproductive milestones like menarche and menopause.
Carried by the majority of individuals in most studied populations, including approximately 70-85% of European ancestry groups.
Intermediate FSHB promoter activity
Individuals with this genotype carry one copy of the variant associated with altered FSH regulation. Studies suggest this may correlate with subtle differences in menstrual cycle length or reproductive timing compared to those without the variant.
Carried by roughly 1 in 5 to 1 in 6 people of European ancestry; it is less common in East Asian populations.
Altered FSHB promoter activity
This genotype is associated with lower circulating levels of follicle-stimulating hormone (FSH). Research links this profile to longer menstrual cycles and potentially later age at menopause, as well as associations with polycystic ovary syndrome (PCOS) risk in some populations.
This is the least common genotype, typically found in approximately 1-2% of individuals of European ancestry.
Genomic Context and Molecular Function
The single nucleotide polymorphism rs11031005 is situated on chromosome 11 within the 5-prime upstream promoter regulatory region of the FSHB gene. Follicle-stimulating hormone is an essential heterodimeric glycoprotein composed of a common alpha subunit and a hormone-specific beta subunit encoded by FSHB. Expressed primarily by gonadotrope cells in the anterior pituitary gland, FSH plays a non-redundant biological role in guiding gametogenesis, follicular growth, and estrogen synthesis in females, as well as spermatogenesis in males. Variants in the FSHB promoter region, including rs11031005 and nearby linkage markers such as rs10835638, have been shown to influence transcription factor binding and baseline messenger RNA transcription rates. When regulatory variants alter the transcriptional efficiency of FSHB, systemic circulating levels of follicle-stimulating hormone can shift, triggering ripple effects across downstream reproductive feedback loops.
Phenotypic Associations in Reproductive Health
Genome-wide association studies (GWAS) have repeatedly mapped rs11031005 and its surrounding genomic locus to circulating levels of gonadotropins, including FSH and luteinizing hormone (LH). In clinical epidemiology cohorts, alleles associated with altered FSH expression correlate with changes in female reproductive timing, including the age of natural menarche and the onset of menopause. Furthermore, cohorts assessing complex endocrinopathies frequently identify this locus as a susceptibility factor for polycystic ovary syndrome (PCOS). A lower systemic FSH tone can impair timely follicular maturation, disrupting normal ovulatory cycles and potentially fostering anovulation or ovarian follicular arrest. Conversely, related alleles linked to elevated FSH have shown correlations with altered cycle lengths and differing susceptibilities to hormone-sensitive conditions such as endometriosis.
Strength and Limitations of the Evidence
Evidence connecting rs11031005 to reproductive parameters is rated as moderate. The statistical signal between variation at the FSHB locus and gonadotropin concentrations reaches stringent genome-wide significance across tens of thousands of participants in biobanks such as the UK Biobank and international consortia. However, the direct clinical effect size attributable to rs11031005 alone is relatively modest. It does not cause monogenic ovarian failure or guaranteed infertility; rather, it functions as a quantitative trait locus adjusting population-level hormone distributions by small increments. Furthermore, strong linkage disequilibrium across the 11p14.1 promoter region means that rs11031005 often co-inherits with other functional markers, complicating the attribution of causality exclusively to one specific nucleotide change.
Ancestry and Population Distributions
Allele frequencies for rs11031005 exhibit notable variation across diverse global populations, reflecting distinct ancestral demographic histories. In European reference cohorts, the minor allele frequency (MAF) hovers around 0.15, meaning roughly one in three individuals carries at least one copy of the less common allele. In East Asian populations, the minor allele is somewhat less prevalent, with frequencies typically observed near 0.08. Because baseline hormonal metrics and phenotypic manifestations like PCOS differ in clinical presentation across ethnic groups, researchers emphasize that statistical associations documented in predominantly European or Han Chinese studies must be interpreted cautiously when generalizing to other world ancestries.
Clinical Utility and Practical Context
Understanding your rs11031005 genotype provides interesting educational context regarding common reproductive biology, but it cannot be used to diagnose any medical disorder. Carrying alleles linked to altered FSH levels or higher PCOS risk does not mean an individual will develop clinical symptoms, irregular cycles, or subfertility, because lifestyle, body mass index, insulin sensitivity, and hundreds of other genetic variants exert compounding effects. Genetic test results for rs11031005 should never prompt independent adjustments to medications, ovulation induction protocols, or hormonal therapies. Anyone experiencing persistent menstrual irregularities, pelvic pain, or difficulty conceiving should consult a board-certified gynecologist or reproductive endocrinologist for standard clinical evaluations, such as serum hormone panels and pelvic ultrasound.
How common is this variant?
The minor allele frequency for rs11031005 is estimated at approximately 0.15 in European ancestral populations and roughly 0.08 in East Asian cohorts, making heterozygous and homozygous genotypes common worldwide.
Frequently asked questions
Can rs11031005 test results diagnose PCOS?
No, rs11031005 cannot diagnose polycystic ovary syndrome (PCOS). PCOS is diagnosed clinically using established frameworks like the Rotterdam criteria, which require physical or biochemical evidence such as irregular menstrual cycles, hyperandrogenism, or polycystic ovaries on ultrasound. This SNP only reflects a small, statistical risk factor across broad populations.
Does having a risk allele mean I will struggle to get pregnant?
Not necessarily. While the variant correlates with subtle differences in circulating follicle-stimulating hormone and cycle patterns, many carriers conceive naturally without intervention. Fertility is influenced by a wide array of reproductive, lifestyle, and clinical factors far beyond any single genetic marker.
How does FSHB affect the menstrual cycle?
The FSHB gene provides instructions for the beta subunit of follicle-stimulating hormone, which stimulates the growth and selection of ovarian follicles during the follicular phase of the cycle. Variations in hormone levels can influence how rapidly follicles mature, subtly altering menstrual cycle length and the timing of ovulation.
Should I change my fertility medications based on this variant?
No, you should never modify fertility drugs, dosages, or hormone treatments based on direct-to-consumer genetic findings. Clinical protocols rely on real-time diagnostic tests, such as serum hormone assays and ultrasound monitoring, interpreted directly by your treating healthcare team.
Sources & further reading
Educational information only, last refreshed 9/6/2026. 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.