Constitution of semen samples from XYY and XXY males as analysed by in-situ hybridization.

A brightfield microscopical in-situ hybridization (ISH) technique was applied to semen samples of two 47,XYY males, one 46,XY/47,XXY/XXY male with fertility problems, and two normal 46,XY men, who served as controls. The use of a standardized nuclear DNA decondensation method, together with double-target ISH and morphological staining, allowed an accurate study of the sex chromosomal content and morphology of spermatozoa. In the males carrying an extra sex chromosome, we detected X- and Y-bearing spermatozoa in a ratio which did not differ significantly from the 1:1 ratio found in normal males. Aneuploidy for the sex chromosomes was found in approximately 15% of the spermatozoa of both XYY males and in 3% of the XXY male. The most striking finding was the relatively low percentage of spermatozoa in these patients, with an average of 65% in the XYY males and 84% in the XXY male. The other cells represented immature germ cells (IGC), including spermatogonia and spermatocytes arrested at various stages of spermatogenesis. Apparently, in XYY or XXY men, these IGC are shed into the semen to an increased extent as compared to normal, fertile men. The sex chromosome constitution of these IGC was heterogeneous. However, the finding that the majority of spermatozoa in semen of 47,XYY and 47,XXY males carried a single sex chromosome strengthens the hypothesis that a 46,XY germ cell line must be present, apparently with a proliferative advantage over the 47,XYY or 47,XXY cells.