lissencephaly true ORDO:102009 SNOMEDCT_US_2018_03_01:23024003 UMLS_CUI:C0266463 UMLS_CUI:C0266483 MESH:D054082 OMIM:615191 ICD10CM:Q04.8 NCI:C103921 ICD10CM:Q04.3 OMIM:300215 disease_ontology OMIM:614019 DOID:0050453 OMIM:611603 OMIM:607432 Xref MGI. OMIM mapping confirmed by DO. [SN]. GARD:12291 Lissencephaly is a malformation of cortical development, where there is deficient gyration (folding) in the cerebral cortex, resulting in absent gyri (agyria) and/or broad simple gyri (pachygyria). OMIM:300067 A congenital nervous system abnormality characterized by the absence of folds in the cerebral cortex and caused_by defective neuronal migration during the 12th to 24th weeks of gestation. Malformations of Cortical Development