Inherited congenital normofunctional testicular hyperplasia and mental deficiency. A corroborative study.

Three 46,XY unrelated individuals out of 84 postpubertal male inpatients with severe mental deficiency in a psychiatric hospital were found to have megalorchidia and macrogenitosomia. One of the cases had a similarly affected brother. Endocrine studies were performed in two of the cases with similar results. Normal plasma levels of pituitary gonadotropins were found. A normal testicular function was demonstrated by the finding of normal: (a) baseline plasma testosterone levels and a significant rise following human chorionic gonadotropin administration, (b) sperm analysis, and (c) morphology and cell architecture of the testes. These results were compatible with normofunctional testicular hyperplasia confirming previous observations and allowing the definite individualization of a syndrome with mental deficiency probably due to an X-linked recessive mutation.