However, considering our results and the frequency of mutations in these genes in cases of intellectual disability, autism, epilepsy and schizophrenia (O'Donnell-Luria et al., 2019; Singh et al., 2016; Hiraide et al., 2018), it is tempting to hypothesise an evolutionarily conserved role for KMT2F and KMT2G in nervous system development, which deserves further investigation. This evidence concerns the gene SETD1B and schizophrenia.