The female and the fragile X reviewed

Nearly 15 years ago, female carriers of the fragile X mental retardation sy ndrome were noted to have an increased incidence of tu in pregnancies. Sinc e then, much evidence has accumulated supporting the notion of ovarian dysf unction in fragile X carriers, in the forms of increased dizygotic twinning and premature ovarian failure. However, despite a decade and a half of res earch regarding this association, the underlying mechanism remains a myster y. This article reviews the population-based studies that have examined thi s association and discusses possible reasons for the variations in results. In addition, results from more recent studies on endocrine function in fra gile X carriers are discussed. These data, when considered in conjunction w ith our emerging understanding of the molecular biology of the fragile X ge ne (FMR1) and its protein product (FMRP), are beginning to elucidate possib le mechanisms for the association between fragile X syndrome and ovarian dy sfunction.