Clinical, pathologic, and genetic findings in a case of 46,XY pure gonadal dysgenesis (Swyer's syndrome). II. Presence of H-Y antigen.

Evidence that expression of histocompatibility-Y (H-Y) antigen on human cells is determined by a Y-linked gene is provided by data demonstrating that male subjects with two Y chromosomes have higher antigen levels than male subjects with one Y chromosome. The widespread evolutionary conservation of H-Y antigen and its association with the Y chromosome suggest that the antigen has a specific, crucial function. We surmise that this function is the differentiation of the embryonic gonad into whichever mature gonad, testis or ovary, typifies the heterogametic sex of each species. Of particular interest are individuals whose gonadal sex does not correspond to their somatic genotype. In the present article, we report positive results in the first case of 46,XY pure gonadal dysgenesis (Swyer's syndrome) to be typed for H-Y antigen. This case suggests that the presence of H-Y antigen may not be sufficient to complete masculinization of the embryonic mammalian gonad. Alternatively, a mutant gene may govern expression of a cell surface component which cross reacts with H-Y antigen but which lacks the ability to function in the virilization of the gonad.