FSHR rs1394205: What Your Genotype Means
The single nucleotide polymorphism rs1394205 is a regulatory genetic variant situated in the 5'-untranslated promoter region (often designated -29 G>A) of the follicle-stimulating hormone receptor (FSHR) gene. Functional and clinical studies indicate that the minor A allele decreases FSHR promoter activity, which can lead to reduced receptor density on target cells. Consequently, this variant has been investigated for its association with altered ovarian response during controlled ovarian hyperstimulation and variations in baseline gonadotropin levels.
What each genotype means
Typical FSH receptor expression
This genotype represents the common version of the FSHR promoter region. Research suggests that individuals with this genotype typically exhibit standard receptor expression levels compared to those carrying the A allele. If you are undergoing fertility treatments, your clinician may use this information alongside other clinical factors to help determine your expected ovarian response.
This is the most common genotype in many populations, though frequencies vary significantly by ancestry.
Intermediate FSH receptor sensitivity
Carrying one copy of the A allele may be associated with a slight reduction in the number of FSH receptors compared to the GG genotype. Studies indicate this can lead to lower ovarian sensitivity during controlled ovarian hyperstimulation, potentially requiring adjustments in medication dosage. Please discuss your specific fertility treatment plan and any concerns about medication response with your reproductive endocrinologist.
This heterozygous genotype is common, appearing in a significant portion of the population across various ancestries.
Reduced FSH receptor sensitivity
Individuals with this genotype have two copies of the A allele, which has been associated in some studies with lower FSH receptor expression and reduced ovarian sensitivity to stimulation. This may influence how your body responds to fertility medications, potentially requiring higher doses of FSH to achieve the desired clinical outcome. Always consult with your fertility specialist to interpret these findings in the context of your personal medical history and treatment goals.
This genotype is less common than the GG or GA genotypes, with its prevalence varying by ethnic background.
What Is rs1394205 and Where Is It Located?
The variant rs1394205 represents a single nucleotide transition from guanine (G) to adenine (A) located at position -29 within the core promoter region and 5'-untranslated region (5' UTR) of the FSHR gene on chromosome 2p16.3. Unlike missense variants that alter the amino acid sequence of the final protein, promoter variants lie upstream of the coding sequence and influence the regulatory machinery that controls how frequently a gene is transcribed into messenger RNA. Molecular biology investigations demonstrate that the substitution from G to A disrupts an Ets-1 transcription factor binding motif. In vitro luciferase reporter assays in cellular models have shown that constructs containing the A allele exhibit roughly 56% of the promoter activity seen with the standard G allele. Because the genetic code within the coding exons remains identical, the receptor protein itself is structurally intact, but fewer receptor copies may be synthesized on the surfaces of target cells.
The Biological Role of the FSHR Gene
The FSHR gene encodes the follicle-stimulating hormone receptor, a member of the G protein-coupled receptor family primarily expressed in gonadal tissues. In females, FSHR is localized to the granulosa cells of developing ovarian follicles, where binding of follicle-stimulating hormone (FSH) triggers intracellular cyclic AMP (cAMP) production, drives follicular maturation, and stimulates estrogen synthesis. In males, the receptor is located on Sertoli cells within the testes, playing a critical role in spermatogenesis. Because FSH signaling directly governs the sensitivity of ovarian follicles to both natural hormone surges and therapeutic gonadotropins, subtle alterations in FSHR expression can influence reproductive physiology. A lower abundance of receptors may require higher circulating concentrations of FSH to elicit standard cellular responses, creating downstream variations in follicular growth or circulating hormone levels.
Clinical Evidence and Controlled Ovarian Stimulation
Clinical interest in rs1394205 centers primarily on reproductive medicine, particularly during in vitro fertilization (IVF) and controlled ovarian hyperstimulation (COH). Multiple small-to-moderate cohort studies have observed that female carriers of the AA genotype express significantly lower FSHR levels in granulosa cells and often require higher cumulative doses of exogenous gonadotropins (recombinant FSH) to achieve adequate follicular recruitment compared to GG carriers. Additionally, research in male cohorts has identified modest statistical associations between the A allele and higher baseline serum FSH concentrations, consistent with compensatory feedback. However, overall evidence remains categorized as limited. Several independent cohorts and diverse populations have failed to replicate significant differences in oocyte retrieval numbers, pregnancy outcomes, or ovarian reserve markers like anti-Müllerian hormone (AMH). Because results vary across studies and ethnic cohorts, rs1394205 is currently considered a modulating trait rather than a primary clinical diagnostic marker.
Population Frequency and Diversity
The frequency of the rs1394205 alleles varies across global ancestries, though both the G and A alleles are common worldwide. In European populations, the minor A allele typically displays an allele frequency ranging between 0.35 and 0.45, meaning that heterozygous individuals (GA) and homozygous minor individuals (AA) represent a substantial portion of the population. In East Asian populations, the A allele frequency is somewhat lower, commonly observed between 0.20 and 0.30. Because the variant is common, harboring one or two copies of the A allele is considered a natural genetic variation rather than a rare pathogenic mutation. Frequency variations among diverse ancestral cohorts highlight why associations seen in one demographic may not always translate uniformly to other populations.
What You Can and Cannot Conclude from Your Genotype
Discovering your rs1394205 genotype provides interesting educational context regarding hormone receptor regulation, but it does not represent a diagnosis of infertility, ovarian failure, or reproductive failure. Complex reproductive outcomes rely on an interplay of age, overall ovarian reserve (measured clinically via AMH and antral follicle counts), lifestyle factors, and many other genetic loci. Genotype alone cannot determine whether an individual will respond successfully to fertility medications or experience spontaneous pregnancy. For patients planning or undergoing assisted reproductive technologies, stimulation protocols and medication dosing should always be determined by a qualified reproductive endocrinologist or clinical team using established biomarkers and clinical monitoring. Genetic data should never be used to initiate, alter, or discontinue any medical treatment independently.
How common is this variant?
The minor A allele occurs at an estimated frequency of 0.35 to 0.45 in populations of European ancestry and approximately 0.20 to 0.30 in East Asian populations. Consequently, the heterozygous GA genotype is widespread, while the AA genotype is present in roughly 5% to 18% of individuals depending on ancestral background.
Frequently asked questions
Does having the rs1394205 AA genotype cause infertility?
No, having the AA genotype does not cause infertility. It is a common natural regulatory variant that slightly modulates receptor expression rather than disabling receptor function. Many people carrying this genotype conceive spontaneously without any difficulty.
How does rs1394205 affect IVF medication dosing?
Some clinical studies have found that women with the AA genotype may require slightly higher total doses of recombinant FSH during ovarian hyperstimulation due to lower receptor density. However, because clinical evidence is mixed, fertility specialists rely on proven biomarkers such as AMH, antral follicle counts, and age to establish and adjust gonadotropin dosages.
Can men be affected by the rs1394205 variant?
Yes, because the FSHR gene is also expressed in the Sertoli cells of the testes, researchers have evaluated rs1394205 in men. Studies have observed modest associations between the A allele and slightly higher baseline serum FSH concentrations, but it is not considered an established cause of male infertility or abnormal semen parameters.
Is rs1394205 testing routinely used in clinical practice?
Genetic testing for rs1394205 is not currently part of routine clinical fertility guidelines or standard pharmacogenomic panels. While it remains a topic of pharmacogenetic research, reproductive specialists primarily utilize hormonal blood tests and ultrasound monitoring to guide individual patient protocols.
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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