Urinary tract malformation in the XYY male

Phenotypic expression of the 47,XYY chromosome complement in man has been investigated mostly in terms of the central nervous system. Evidence is presented here to suggest that urinary tract malformation may be a component of the XYY syndrome; this should be taken into account when counselling parents of children with this chromosome anomaly, and in making decisions when an affected foetus is diagnosed antenatally.