Investigation of genetic markers in a true hermaphrodite with chi 46,XX/46,XY.

We documented a new case of chi 46,XX/46,XY true hermaphroditism substantiated by the evaluation of chromosomal heteromorphism in banded preparations. The patient, a 12-year-old Japanese boy with ambiguous external genitalia, was seen because of abnormal breast development. Surgical exploration showed the right gonad to be an ovotestis and the left gonad to be an ovary. Cytogenetic studies revealed cell admixtures of 46,XX and 46,XY karyotypes in peripheral lymphocytes, skin fibroblasts, and gonadal fibroblasts. From the pedigree studies, the paternal double genetic contributions were evidenced by the differences of sex chromosomes and the blood group types for the ABO and MNSs systems in the two cell lines of the patient. The maternal double genetic contributions were confirmed by the inheritance of Q-fluorescent markers on chromosomes 13 and 22 and by alleles for the Kidd blood group system.