As an example, mutations in methyl-CpG binding protein 2 (MeCP2), leading to Rett syndrome, cause genome-wide amplification of histone acetylation, promoting the investigation into the association of the chromatin environment of MeCP2 target genes and the density of histones H1, H2B and H3 [115]. Here, MECP2 is linked to atypical Rett syndrome.