KIF1B and neurodevelopmental disorder: Seven other missense variants from the current cohort were identified in genes previously associated with a heterozygous neurodevelopmental disorder: NAA15 (p.D540Y) in proband 03, RELN (p.G3368R) in proband 05, HCN1 (p.G74_E75insGGG) in proband 08, CIC (p.C444F) in proband 06, STXBP1 (R100W) in proband 09, and KIF1B (p.Y96C) in proband 02.