Loss of function variants in exon 2 of KANSL1 (e.g. G306*) are known to cause Koolen De Vries syndrome (KdVS) [30, 56], but variants in exon 8 [57] identified on the H2 haplotype have not been associated with neurodevelopmental disorders. This evidence concerns the gene KANSL1 and Koolen-de Vries syndrome.