Gray matter heterotopia

Gray matter heterotopia are common malformations of cortical development. F rom a clinical perspective, affected patients are best divided into three g roups: subependymal, subcortical, and band heterotopia (also called double cortex). Symptomatic women with subependymal heterotopia typically present with partial epilepsy during the second decade of life; development and neu rologic examinations up to that point are typically normal. Symptoms in men with subependymal heterotopia vary, depending on whether they have the X-l inked or autosomal form. Men with the X-linked form more commonly have asso ciated CNS and visceral anomalies; their development is typically abnormal. Symptomatic men with the autosomal variety have clinical courses similar t o symptomatic women. Both men and women with subcortical heterotopia typica lly have congenital fixed neurologic deficits and develop partial epilepsy during the second half of the first decade of life. The more extensive the subcortical heterotopia, the greater the deficit; bilateral heterotopia are almost invariably associated with severe developmental delay or mental ret ardation. In general, band heterotopia are seen exclusively in women; men w ith a mutation of the related gene (called XLIS or DCX) usually die in uter o or have a much more severe brain anomaly. Symptoms in affected women vary from normal to severe developmental delay or mental retardation; the sever ity of the syndrome is related to the thickness of the band of arrested neu rons. Nearly all affected patients that come to medical attention have epil epsy, with partial complex and atypical absence epilepsy being the most com mon syndromes. Some of the more severely affected patients develop drop att acks.