lissencephaly spectrum disorders cobblestone lissencephaly UMLS:C0431376 Orphanet:51577 Cobblestone lissencephaly is a rare central nervous system malformation which includes a group of diseases that are characterized by a bumpy (or pebbled) appearance of the cerebral cortex, associated with a thickened cortex, reduction in normal sulcation, ventriculomegaly and reduced, abnormal white matter, as well as brainstem and cerebellum hypoplasia and corpus callosum agenesis. Patients generally present variable degrees of developmental delay, hypotonia and ocular abnomalities, however muscular and ocular involvement may be absent. MONDO:0018869 lissencephaly type 2 SCTID:253149002 NANDO:1201072 MESH:D054222 GARD:0003277 MEDGEN:96562