NDEL1 and subcortical band heterotopia: Through whole-exome sequencing (WES), this study identified, for the first time, two unrelated patients with pachygyria, with or without subcortical band heterotopia (SBH, also known as double cortex), both carrying the same de novo NDEL1 (NM_030808.5) missense variant c.314G > C; p.Arg105Pro (p.R105P).