RBL2 and Intellectual disability: Exome sequencing in two siblings with severe intellectual disability, stereotypies and dysmorphic features identified biallelic loss‐of‐function variants c.556C>T, p.(Arg186Ter) and a deletion of exon 13–17 in RBL2 (NM_005611.3), establishing RBL2 as a candidate gene for an autosomal recessive neurodevelopmental disorder.