Encefalopatia epilettogena grave in un bambino affetto da sindrome 47,XXY.

Neuropsychiatric manifestations of Klinefelter's syndrome are heterogenous and epilepsy usually shows a benign course. We describe a 4-year-old boy with a severe epileptic encephalopathy presenting 47,XXY cariotype. Other metabolic, genetic and neuroradiological investigations were unrevealing. The random inactivation of an additional X chromosome could be responsible for the phenotype severity in this child.