Peculiar mosaicism 47,XYY/48,XYYY/49,XYYYY in man.

The chromosome analysis in a 9 years-old boy showed the presence of three cell lines : 47,XYY (28%) ; 48,XYYY (68%); 49,XYYYY (4%). Since the most frequent cells bear three Y chromosomes and the karyotype of the propositu's father is normal, it is suggest that the propositus arose from an YYY sperm and that the observed mosaicism originated from a subsequent postzygotic non-disjunction.