MECP2 and Rett syndrome: Based on the MECP2 genotype, the patients with RTT harbored the following MECP2 pathogenic mutations: R106W (3%), T158M (12.1%), R168X (6.1%), R255X (12.1%), R270X (12.1%), R294X (6.1%), C-terminal deletions (18.2%), large deletions (6.1%), and non-hotspot mutations (24.2%).