Gonadoblastoma in Turner syndrome patients with nonmosaic 45,X karyotype and Y chromosome sequences.

Turner syndrome (TS) is a disorder caused by partial or complete X-chromosome monosomy. Studies in TS patients with different karyotypes have demonstrated the presence of Y-chromosome-derived sequences (4-61%). Early detection of Y-chromosome sequences in TS is of great importance because of the high risk of gonadal tumor development. We investigated the presence of Y-chromosome sequences in TS patients with a 45,X karyotype. One hundred seven unrelated 45,X Mexican TS patients recruited between 1992 and 2003 were included. Y-chromosome-derived sequences were found by polymerase chain reaction in 10 (9.3%) patients. Six subjects underwent gonadectomy and in one of them a gonadoblastoma was found; another developed a gonadoblastoma with dysgerminoma. Because of the high proportion (33%) of gonadal tumors in patients with Y-chromosome sequences found among our patients of mestizo origin, adequate counseling regarding a gonadectomy should be given.