However, in particular among the PPI network genes, we did observe de novo mutations in autism probands that were not identified in healthy siblings, including one missense mutation in BRD1, one missense mutation in CHD4, and four disruptive and two missense mutations in SUV420H1 [40, 41], as well as rare disruptive mutations seen only in schizophrenia cases and not in controls (in BRD1, ING5, YWHAZ, NAP1L4, MYST2, and HIST1H3A) [42]. Here, CHD4 is linked to schizophrenia.