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.