MBD1 and Rett syndrome: MBD5 is a member of the methyl-CpG-binding domain (MBD) family, which also comprises MBD1-MBD6, SETDB1, SETDB2, BAZ2A, and BAZ2B and MeCP2, the causative locus in Rett syndrome (RTT [MIM 312750]) [9,10].