Dizygotic twin with XXYY chromosome aneuploidy and diffuse sexual orientation, with review of 30 XXYY cases.

A case of XXYY genotype with sexual psychopathology is described, and 30 previous cases are reviewed. Consideration of family history emphasizes a statistically high rate of twinning and firstborns. Review of the clinical appearance of the patients described indicates that obesity, tallness, and feminine features are more common in association with the XXYY karyotype but by no means pathognomonic of it. The incidence of other pathology, particularly cardiovascular and orthopedic conditions and hypogonadism, appears to be high in a group of XXYY patients. Psychometric evaluation of these patients suggests that low intelligence is a feature and that the incidence of EEG abnormalities may be high, but that personality, delinquency, aggression, and sex interest are not specific for this group.