We expect that this approach will be particularly valuable with regard to genetic testing for a variety of overgrowth disorders particularly as mutations in additional epigenetic regulators, histone-lysine N-methyltransferase (SETD2) (ref. 21) and DNA methyltransferase 3 (DNMT3A)22, have recently been reported to cause distinct overgrowth syndromes. Here, SETD2 is linked to overgrowth syndrome.