For instance, some monogenetic ASDs that are caused by the mutations in genes encoding epigenetic or transcription factors, e.g., methyl CpG binding protein 2 (MeCP2) in Rett Syndrome (Yasui et al., 2013) or the above mentioned TCF4 in PTHS, respectively, could affect transcriptional machinery required for adequate expression of Cx43 in EGCs (reviewed in Oyamada et al., 2013) and, in turn, affect GI motility in patients with ASD. Here, MECP2 is linked to Pitt-Hopkins syndrome.