Two cases of 48,XXYY: with discussion on the behaviour of prepubertal and postpubertal patients

Two cases of 48,XXYY are presented, one prepubertal and the other postpubertal. Their dysmorphic features are described and compared to those reported previously. Xg blood grouping was uninformative in determining the origin of the extra X chromosome. The differences in prepubertal and postpubertal behaviour problems are discussed.