Abnormal cerebral cortical convolutions in an XYY fetus.

Because of maternal disease a pregnancy was electively terminated at 21 weeks of fetal gestation. At autopsy the fetus showed an abnormal pattern of cerebral cortical convolutions involving the frontal lobes. Karyotpic analysis revealed an XYY sec chromosome constitution. This observation, if confirmed in other XYY cases, raises the possibility that a developmental abnormality of the cerebral cortex may be involved in the higher-than-normal risk for behavioral disability exhibited by men with this genotype.