Y chromosome specific DNA probe in the diagnosis of a patient with mos 45,X/46,XYnf.

In a patient with mos 45,X/46,XYnf, the diagnosis was confirmed with a Y chromosome-specific DNA probe, Y-190. The patient was a phenotypic female without Turner syndrome stigmata other than short stature. She showed some evidence of virilization and high serum testosterone. Her peripheral blood karyotype was mos 45,X/46X, +mar. Although this marker chromosome resembled a Y chromosome, there was no quinacrine bright region on its long arm. Southern blot analysis of her peripheral blood mononuclear cell DNA with Y-190 as a probe showed strong hybridization with this probe. Gonadectomy was performed, and bilateral gonadoblastomas were found.