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

Background: 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. Methods: 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. Results: 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. Conclusions: we therefore conclude that intermediate sized FMR1 CGG repeat alleles should not be considered a high-risk factor for POF based on current evidence