FISH and PCR analysis of the presence of Y-chromosome sequences in a patient with Xq-isochromosome and testicular tissue

Mixed gonadal dysgenesis includes a heterogeneous group of different chromo somal. gonadal, and phenotypic abnormalities, characterized by the presence of a testis on one side and streak or an absent gonad on the other, persis tence of mullerian duct structures and/or wolffian derivatives, and a varia ble degree of genital ambiguity. were, we describe a patient with virilized external genitalia and phenotypic features of Turner syndrome, whose blood karyotype was 45,X/46,X,i(Xq). The presence of a unilateral dysgenetic tes tis was confirmed by histopathology. Using fluorescence in situ hybridizati on (FISH) and polymerase chain reaction (PCR)-based analysis to detect Y-sp ecific sequences, Y-chromosome material was not detected. To date, this is the first case reported of Xq-isochromosome associated with the presence of testicular tissue.