1 Genetic and Endocrine Unit, Department of Pediatrics, State University of New York, Upstate Medical Center, Syracuse, New York
A 10-year-old boy with learning difficulties, tall stature, prognathism, malformations of the hands, and abnormal dermatoglyphics is reported. Chromosomal analyses revealed an XY/XYY mosaicism with 3.5% XY and 92% XYY cells. Labelling studies of the chromosomes revealed that the two Y chromosomes in the XYY cell line replicate similarly and later than the other members of the C group. This appears to be the first described case of XY/XYY mosaicism.
Submitted on September 12, 1967