[Phenotype-genotype correlation in mutations of the gonadotrophin receptor gene in women]

Different mutations have been described in LH and FSH genes as well as in their receptors. These mutations are either activating (gain of function), or inhibiting (loss of function). Activating mutations are expressed as a dominant trait, thus in the heterozygous state, whereas inhibiting mutations are only expressed when both alleles bear the mutation. Inactivating mutations of FSH receptor gene, in women, are associated with primary ovarian insufficiency. Inactivating mutations of LH receptor gene have also been described, most often in XX patients whose families also include cases of male pseudohermaphrodism. Clinically, these women suffer from primary amenorrhea but with normal development of breasts and the hair system. Infertility is constant. LH blood levels are increased, estradiol blood levels are those encountered at the beginning of the follicular phase (50-70 pg/ml). The discovery of these mutations allows a better understanding of some genotypes and is helpful in advancing our knowledge of these receptors.