Source:http://linkedlifedata.com/resource/umls/id/C0265219
JABL: A developmental defect of the brain caused by incomplete neuronal migration and characterized by smoothness of the surface of the brain (lissencephaly) occurring in association with absence of the sulci and gyri (agyria) and thickening of the cerebral cortex with four rather than six layers (pachygyria), microcephaly, characteristic facial appearance, retarded growth and mental development, neurological complications, and multiple abnormalities of the brain, kidneys, heart, gastrointestinal tract, and other organs. Lissencephaly, once considered as synonymous with Walker-Warburg syndrome and Norman-Roberts syndrome, is now recognized as a component of several other syndromes. Type I (the classical form) is a component of Miller-Dieker and Norman-Roberts syndromes, also occurring as a separate entity; Type II the Walker-Warburg and muscle-eye-brain syndrome, also occurring in the Neu-Laxova syndrome.