The Ala307Thr polymorphism of the follicle-stimulating hormone receptor (FSHR) gene is associated with the dose of recombinant FSH received during IVF/ICSI treatment

OBJECTIVE: Follicle-stimulating hormone (FSH) is essential for folliculogenesis, acting through the follicle-stimulating hormone receptor (FSHR) that is present on the membrane of granulosa cells. Polymorphisms in the FSHR gene may lead to an altered pattern of receptor expression on the cell surface or to changes in affinity for FSH. The aim of this prospective study was to detect any association between the follicle-stimulating hormone receptor (FSHR) gene Ala307Thr polymorphism (rs6165) and ovarian reserve, ovarian response or clinical results in IVF/ICSI treatment. METHODS: This prospective cohort study included 450 women who underwent IVF/ICSI cycles. DNA was extracted from peripheral blood, and the Ala307Thr FSHR polymorphism (rs6165) was genotyped using the TaqMan SNP genotyping assay. Participants were divided into three groups according to their Ala307Thr FSHR genotype: Thr/Thr (n:141), Thr/Ala (n=213) and Ala/Ala (n=96). The results were tested for associations with age, anti-Mullerian hormone (AMH) levels, antral follicle count (AFC), total dose of r-FSH, follicle size, number of retrieved oocytes, and clinical outcome of IVF/ICSI cycles. The statistical analyses were performed using Fisher’s exact test and the Kruskal‒Wallis test. RESULTS: An association between the genotype of the FSHR (Ala307Thr) polymorphism and the dose of r-FSH was observed. Patients with the Ala/Ala genotype received a higher r-FSH dose than patients with the Ala/Thr (p=0.0002) and Thr/Thr (p=0.02) genotypes. No other correlation was observed. CONCLUSION: The Ala/Ala genotype was associated with the use of higher doses of recombinant FSH (r-FSH), suggesting that homozygosis of this allelic variant (Ala) provides lower sensitivity to r-FSH.