H-Y antigen in 2 patients with XY, q- karyotypes and with female and male phenotypes

The H-Y antigen is a histocompatibility antigen present in males but absent in normal females. Although the precise location of the gene on the Y chromosome is not known, it has been suggested that the H-Y gene may be on the short arm of the Y chromosome or on the long arm very near the centromere. It has also been hypothesized that the antigen may be directly related to testicular differentiation of the premordial gonad. H-Y antigen studies were undertaken in 2 adult patients with deletions of the long arm of chromosome Y. Case 1. A 21-year-old black male, presented with short stature, obesity, an undescended left testis, and decreased facial hair. Histologic examination of the left testis removed at surgery demonstrated immature testicular tissue. Chromosome analysis revealed a 45,X/46,XY,q- pattern Case 2. An apparently normal female, was observed to have an enlarged clitoris on routine newborn examination. Separate urethral and vaginal orifices were present, and there were no gonads palpable. At the age of 18 months the child was hospitalized for investigation: cytoscopy and vaginoscopy were normal, and a normal cervix was visualized. The urinary 17-ketosteroid excretion was 1 mg/24 hr. At the age of 2 years testes were found. Surgical exploration revealed a normal infantile uterus and fallopian tubes. Biopsy of both gonads demonstrated closely packed immature seminiferous tubules and supporting cells indicative of immature testes. There was no ovarian tissue. At the age of 3 years bilateral gonadectomy was performed. The patient was rehospitalized at the age of 6 years for clitoridectomy. Chromosome analysis revealed a 45,X/46,XY,q- pattern. H-Y antigen expression on peripheral leukocytes was determined serologically using a sperm cytotoxicity test and a mixed hemadsorption-hybrid antibody test described elsewhere. Both patients were typed H-Y+. Occurrence of H-Y antigen on the cells of both male and female patients with similar sex chromosomal constitutions supports earlier evidence that the controlling gene is Y chromosomal and does not depend for its expression on a male hormonal milieu.