Gonadal dysgenesis with 45,X/46,X,dic(Yp) mosaicism.

A female patient with a gonodal mucinous cystadenoma on the right side and a gonadoblastoma on the left was found to be a 45,X/46,X,dic (Yp) mosaic. This brings the total number of cases with dicentric Y chromosome reported to date to 23. Together with the available evidence, the information derived from this case supports the hypothesis that the gene on the long arm of the Y chromosome is responsible for the initiation of testicular differentiation, whereas that on the short arm is responsible for the maturation of the testes.