The mRNA expression of ZNf587 was significantly higher in children with ASD (n = 16, p = 0.027) and FXS-ASD (n = 16, p = 0.054) compared to TD (n = 8) children, who confirmed the observed hypomethylation profile of ZNf587 in both children with ASD and FXS-ASD compared to TD. This evidence concerns the gene ZNF587 and fragile X syndrome.