[Gonadal dysgenesis in Turner syndrome].

This review article summarizes the current knowledge on the development of gonadal dysgenesis in Turner syndrome. The degree of gonadal dysfunction is well correlated with the size of unpaired region of the sex chromosomes and is independent of the dosage of gene(s) on the sex chromosomes. Thus, it is deduced that sex chromosome aberrations result in meiotic pairing failure of homologous chromosomes, leading to accelerated oocyte loss and resultant gonadal dysgenesis. Although the underlying factor responsible for the oocyte loss remains to be determined, it is likely that activation of apoptotic mechanism to prevent the generation of abnormal gametes plays an essential role in the rapid oocyte degeneration.