An XX male: cytogenetic and endocrine studies.

A 3 year old black male with ambiguous genitalia had a 46, XY karyotype in a bone marrow culture and an intermediate buccal smear result, suggestive of a mosaic of chromatin positive and chromatin negative cells. Upon re-evaluation at age 15 years, he has a 30% positive buccal smear and a 46, XX karyotype in cultures of peripheral blood lymphocytes, skin fibroblasts, bone marrow, and testis. No Y-body fluorescence was detectable in interphase cells from the testicular biopsy or the various cultures. The testicular biopsy appeared similar to that of XXY males, and primary hypogonadism was documented by elevated LH (107 mIU/ml) and FSH (57 mIU/ml) levels in conjunction with low testosterone (142 ng/100 ml). Administration of hCG produced qualitatively normal acute responses of testosterone and estrogens. The cytogenetic data provide support for the theory that at least some XX males once had a Y-containing cell line which was subsequently lost.