Microcephaly-polymicrogyria-corpus callosum agenesis syndrome is a rare, genetic, central nervous system malformation syndrome characterized by marked prenatal-onset microcephaly, severe motor delay with hypotonia, bilateral polymicrogyria, corpus callosum agenesis, ventricular dilation, small cerebellum and early lethality. The disease is microcephaly-polymicrogyria-corpus callosum agenesis syndrome (MONDO_0015745, a Monarch Disease Ontology term).