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.
Deletion of the short arm of chromosome 17. As initially reported, the syndrome consisted mainly of cleft palate and congenital heart defect. The phenotype was later expanded to include brachycephaly, midfacial hypoplasia, broad nasal bridge, highly arched palate, mandibular prognathism, malformed ears, short hands, mental retardation, and other less constant abnormalities.
a rare chromosomal disorder characterized by abnormalities of the craniofacial area (brachycephaly, prognathism, cleft palate), delays in the acquisition of skills requiring the coordination of mental and muscular activities, mental retardation; most affected individuals experience speech delays that may occur in association with hearing impairment; behavioral abnormalities may include hyperactivity and self-destructive behavior.
2006 ICD-9-CM Diagnosis Code 758.33
