MECP2 represents methyl CpG-binding protein, a gene that provides instructions for making MeCP2 protein. 

According to Genetics Home Reference, "The exact function of this protein is unclear. It appears to help regulate gene activity (expression) by modifying chromatin, the complex of DNA and protein that packages DNA into chromosomes. The MeCP2 protein is present in cells throughout the body, although it is particularly abundant in brain cells."

MeCP2 protein is important for the function of cells, including neurons, and is believed to help process messenger RNA (mRNA).

Mutations on MECP2 have been associated with Rett Syndrome, some forms of intellectual disability, and autism.