Chromosomal protein that binds to methylated DNA. It can bind specifically to a single methyl-CpG pair. It is not influenced by sequences flanking the methyl-CpGs. Mediates transcriptional repression through interaction with histone deacetylase and the corepressor SIN3A. Binds both 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC)-containing DNA, with a preference for 5-methylcytosine (5mC). Interacts with FNBP3 (By similarity). Interacts with CDKL5 (PubMed:15917271). Interacts with ATRX; MECP2 recruits ATRX to pericentric heterochromatin in neuronal cells (By similarity). Interacts with NCOR2 (By similarity). Interacts with TBL1XR1; bridges interaction between MECP2 and NCOR1 (PubMed:28348241). Interacts with TBL1X; recruits TBL1X to the heterochromatin foci (PubMed:28348241). Colocalized with methyl-CpG in the genome. Colocalized with TBL1X to the heterochromatin foci. Present in all adult somatic tissues tested. Phosphorylated on Ser-423 in brain upon synaptic activity, which attenuates its repressor activity and seems to regulate dendritic growth and spine maturation. The disease may be caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. The disease may be caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. The MECP2 gene is mutated in Rett syndrome, a severe neurodevelopmental disorder that almost always occurs in females. Although it was first thought that MECP2 mutations causing Rett syndrome were lethal in males, later reports identified a severe neonatal encephalopathy in surviving male sibs of patients with Rett syndrome. Additional reports have confirmed a severe phenotype in males with Rett syndrome-associated MECP2 mutations. The disease is caused by variants affecting the gene represented in this entry. Increased dosage of MECP2 due to gene duplication appears to be responsible for the intellectual disability phenotype. Ten times higher expression levels than isoform A in brain. Truncated N-terminus. IRSA MECP2 variation database