Intermediate sized CGG repeats are not a common cause of idiopathic premature ovarian failure

It is recognized that FMR1 premutation expansions are associated with premature ovarian failure (POF), but the role of smaller repeats at the boundary of premutation and normal is less clear. We have therefore investigated the incidence of these intermediate sized FMR1 CGG repeats (35-58 repeats) in a series of 366 women ascertained because of menopause before the age of 40. We found no significant difference in the incidence of intermediates in cases compared with controls. Thus, we were unable to replicate previous studies showing a positive association, despite a significantly larger sample size. We therefore conclude that intermediate sized FMR1 CGG repeat alleles should not be considered a high-risk factor for POF based on current evidence.