MECP2 and atypical Rett syndrome: A number of observations support the role of EGRs in ASD etiology: (a) as reported earlier, EGR1 displays an excess of de novo mutations (S20 Fig) [50]; (b) variants disrupting EGR binding sites in the Contactin-associated protein-like 2 (CNTNAP2) promoter were reported as risk factors for ASD [58]; (c) MECP2, in which mutations cause Rett syndrome [29,59], was found to be regulated by EGR2 in a positive feedback loop [60]; (d) compared to controls, EGR2 expression is significantly lower in Rett syndrome and ASD brain samples [60], as well as in ASD lymphoblastoid cells [61].