Polymicrogyria is one of many malformations of cortical development, and with grey matter heterotopias, falls in a bewildering group of conditions characterised by abnormalities both in migration of neurons to the cortex and abnormal cortical organization. It is often associated with schizencephaly – indeed schizencephalic cleft is ‘always’ lined by polymicrogyic cortex.

Many well recognised subtypes have been described, and some, such as bilateral perisylvian polymicrogyria have been mapped to a number of specific genetic mutations (e.g. autosomal dominant (22q11.2 and others) )

Although often sporadic or genetic, polymicrogyria is also seen secondary to intrauterine cytomegalovirus (CMV) infection, vascular compromise in twins, or anomaly–mental retardation syndromes including Adams–Oliver syndrome, Arima syndrome, Galoway–Mowat syndrome, and Delleman syndrome.


Barkovich, A.J et al “Classification system for malformations of cortical development” NEUROLOGY 2001;57:2168–2178

Credit: Dr Frank Gaillard