46,XY/48,XYYY mosaicism case report and review of the literature.

A 46,XY (18.9%)/48,XYYY (81.1%) mosaicism in lymphocytes and a 48,XYYY karyotype in skin fibroblasts were found in a 37-year-old obese man suffering from dysplasia of the right hip. As other reported cases, he showed mental retardation and behaviour disturbances with agressiveness, sexual impulsions. Testicular biopsy revealed fibrohyalinization in about 10% of the tubules and subnormal spermatogenesis in the others.