A male subject with 3 Y chromosomes (48, XYYY): a case report.

We describe a male subject with 3 Y chromosomes who presented with complaints of lack of sexual desire and failure to achieve rigid erection. The patient was tall and had markedly incurved little fingers on both hands as well as small testes. Karyotype was 48, XYYY. The patient's parents had normal karyotypes. Endocrinological profile suggested a primary functional disturbance of the gonads. Testicular biopsy demonstrated atrophic seminiferous tubules without spermatogenesis. To our knowledge this case represents the third instance of a man with an 48, XYYY karyotype without mosaicism.