Mixed gonadal dysgenesis: a syndrome of broad clinical, cytogenetic and histopathologic spectrum.

Mixed gonadal dysgenesis (MGD) is an abnormality of sexual differentiation (ASD), which encompasses an heterogeneous group of different gonadal and phenotypic abnormalities. This study describes the main clinical features found in 16 patients with MGD, relating the clinical presentation with cytogenetic evaluation and histopathological findings. For purpose of this study, MGD was considered in those patients who fulfilled the following diagnostic criteria: 1) müllerian and/or wolfflan derivatives; 2) any of the following gonadal characteristics: a) bilateral intrabdominal or scrotal immature testicular tissue; b) intrabdominal or scrotal immature testicular tissue with contralateral streak gonad. Patients were selected from an ASD study which was carried out in Medical Genetic Unit of University of Zulia (UGM-LUZ), Maracaibo, Venezuela, from 1980 to 1997. The following information was extracted from the medical history at UGM-LUZ: age, gender which patient was reared, clinical presentation, cytogenetic evaluation, laparoscopic findings and gonadal biopsy. Sixteen patients fulfilled the diagnostic criteria and ranged in age from 1.2 to 39.4 years with an average of 12.65 years. Only 5 patients were reared as males. Twelve patients consulted for genital ambiguity. Chromosomal evaluation was as following: 8 patients with 45,X/46,XY mosaicism: 5 had a 46,XY normal male karyotype and the remaining patients: 46,XX; 46,XX/46,XY and 45,X/46,Xi(Xq) karyotypes, respectively. All patients showed müllerian derivatives and occasionally wolffian derivatives. Gonadal tumors were present in 2 patients. Molecular studies of genes that govern gonadal development are necessary for a better understanding of the wide heterogeneity present in MGD.