Increased serum FSH in female fragile X premutation carriers with either regular menstrual cycles or on oral contraceptives

Fragile X premutations are known to be a risk factor for diminished ovarian function at a relatively young age. We studied endocrine profiles of female fragile X family members (n = 79) at risk of premature ovarian failure (POF). Of these 79 women aged <40 years, 45 had menstrual cycles, and 34 were using oral contraceptives. Of the women with menstrual cycles, the premutation carriers had higher serum FSH concentrations than women who were not carrying the premutation. Even premutation carriers with regular cycles showed increased serum FSH concentrations. Moreover, premutation carriers using oral contraceptives also demonstrated increased serum FSH concentrations. Irrespective of whether oral contraceptives were used, a serum FSH concentration of > or =15 IU/l was more common in the premutation carriers than in the other women. One premutation carrier using oral contraceptives had a serum FSH concentration of >40 IU/l, the threshold that defines POF. We confirmed that premutation carriers with menstrual cycles demonstrate premature ovarian dysfunction. However, we also found endocrine signs of unrecognized ovarian dysfunction in premutation carriers using oral contraceptives, despite endocrine alterations by oral contraceptives. Premutation carriers may have a poorer prognosis for future pregnancy, either achieved spontaneously or by assisted reproductive technology. We recommend that premutation carriers should be counselled not to wait too long if they wish to start a family.