FSH acts via binding to its specific receptors, the FSHR, possessing a large number of SNPs. The FSHR SNPs at nucleotide position 919 and 2039 in exon 10 are very common (heterozygosity: 0.469) and result in the aminoacid transition Thr/Ala at codon 307 and Asn/Ser at codon 680 respectively. In addition a G/A SNP is found in the promoter region at position −29, with the G allele covering 75% and the A allele 25% of the alleles in Caucasians. In turn, the FSHB gene, encoding the α subunit of the gonadotropin, possesses an interesting SNP in the promoter region (SNP, rs10835638; G/T) 211 bp upstream from the FSHB mRNA transcription start-site, located within a highly conserved region among placental mammals.
Several studies demonstrated that the FSHR SNPs affect ovarian response to FSH in women undergoing assisted reproduction techniques (ART). The FSHR Ser680 genotype is less sensitive to the FSH action in vivo, compared to the FSHR Asn680 genotype. A recent meta-analysis including data available from different ethnic group have confirmed that the marker Ser680 is associated with a poor response during ART, concluding that FSHR genotyping could provide important information to customize the dose of FSH during controlled ovarian hyperstimulation and reinforcing the critical role of FSHR SNPs in assisted reproduction treatment. The FSHR polymorphism G/A at position −29 could modulate ovarian response to FSH as well, since it controls the transcription rate of the mRNA. Data in fertile and infertile men are less clear-cut. Studies in vitro were so far unable to demonstrate the molecular and cellular effects of the SNPs in the FSHR.
Concerning, the FSHB gene studies in males demonstrated that the SNP in the promoter is significantly associated with serum FSH and testosterone levels and that the -221T allele has an increased prevalence in infertile men.
Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.
Funding: This work was supported, however funding details are unavailable.
05 - 09 May 2012
European Society of Endocrinology