Human FSHβ subunit gene is highly conserved

FSH is a pituitary gonadotropin that along with LH plays a key role in the regulation of gonadal function. The gonadotropic hormones are composed of two subunits, the common subunit and the hormone-specific subunit, which determines the binding to specific receptors and induction of biological response. Unlike the LH gene, shown in earlier studies to harbour several amino acid-altering polymorphisms and mutations, information about the eventual sequence variation of the human FSH subunit is not available. In this study, we made sequence analysis and comparison of polymorphisms found in FSH in two Caucasian populations, the Finns and the Danes. It was found that FSH subunit is highly conserved in these populations. Compared with the published sequences, only three silent polymorphisms were detected in the coding regions of the gene, and the promoter sequence was completely identical with the reported sequence. Two of the polymorphisms found were novel, one in the Finnish and one in the Danish population. The results of the sequence analysis show that the human FSH gene is highly conserved and amino acid changing mutations are apparently extremely rare, at least in the samples collected randomly from control populations. This may be due to the crucial role of normal FSH function in the regulation of fertility.