CNTN4 and Down syndrome: Three other cases had well documented microdeletions but penetrance and expressivity of CNVs are known to be variable [Case 10: CNTN4 deletion in ‘Chromosome 3pter-p25 Deletion Syndrome (MIM#613792)’, Case 19: ‘Chromosome 15q11.2 Deletion Syndrome (MIM#615656)’, Case 30: ‘Chromosome 16p11.2 Deletion Syndrome (MIM#611913)’] [25–29].