MECP2 and Rett syndrome: For example, the chromatin modifier, methyl-CpG binding protein 2 (MeCP2), which is famously known for its association with Rett syndrome, which typically falls into the spectrum of autism, normally regulates genes involved in synaptic function, including protocadherin β 1 (PCDHB1) and protocadherin 7 (PCDH7) [13,17].