[A case of XYY syndrome with male infertility and retentio testis].

A case of the XYY syndrome is reported. A 29-year-old man visited our hospital because of infertility and right undescended testicle. He was tall (181 cm) and his intelligence level was below average but his character was not violent. His right testis was touched in his right inguinal region and it was atrophic. Analysis of the semen showed no sperm. The biopsied specimen of his left descended testis as well as right undescended testicle showed spermatogenic arrest. Consequently we speculated that the spermatogenesis was injured by the surplus Y chromosome. On endocrinologic examination, plasma LH and FSH were high and testosterone revealed to be low. These data were slightly abnormal, but similar to those of most previous investigators.