The co-occurrence of developmental language disorder and reading impairment in members of three families with perisylvian polymicrogyria is reported from the State University of Campinas, and University of Sao Paulo, Brazil. The severity of language impairment correlated with the extent of the polymicrogyria, patients with the worst language deficit having diffuse bilateral perisylvian polymicrogyria while patients with mild impairment showing subtle MRI anomalies. 
COMMENT. Polymicrogyria is a cerebral developmental anomaly, characteristically perisylvian in location, giving the cortical surface a pebbled, 'chestnut kernel,' or 'Moroccan leather' appearance. Genetic or acquired causes are described. A causative diagnosis was established in 20 of 48 cases recently reported (Ped Neur Briefs March 2008;22:24) . A genetic cause was suspected in 6 patients with multiple congenital abnormalities and in 4 with consanguineous parents or multiple affected family members. A gestational insult was the probable cause in 7 patients. Polymicrogyria can be localized or diffuse, unilateral or bilateral. The cortex is thickened, without recognizable layers or with 4 layers in place of the usual 6. The brain stem may be hypoplastic, especially involving the pyramidal tracts. In severe cases, the child has spastic diplegia or hemiplegia, mental retardation, and seizures. The MRI has permitted the diagnosis and recognition of milder forms of polymicrogyria, some associated with language and reading disorders, as described in the above study.