XYY males found in a general male population. Cytogenetic and physical examination.

Abstract

Five males with karyotype 47,XYY were found among 3840 men examined for military service, giving a prevalence of 1.30 per 1000. The five XYY males had a normal male phenotype and no physical abnormalities, except for minor columna vertebralis aberrations. There was a slight increase of the β1 fraction of alkaline phosphatases. Testis histology showed impairment of spermatogenesis in all four in whom this examination was made. Electroencephalogram was slightly abnormal in two of the five males. There was a comparatively low urinary excretion of pituitary gonadotrophins, dehydroepiandrosterones and oestrogenes and a comparatively high urinary excretion of 17-ketogenic steroids; these deviations in hormone excretion were, however, not very pronounced.