MECP2-related disorders in males include severe neonatal encephalopathy (OMIM # 300673), intellectual developmental disorder 13 (MRXS13) (OMIM # 300055), pyramidal signs, Parkinsonism and macroorchidism (PPMX) (OMIM # 300055), Rett syndrome classical phenotype (OMIM #312750), and MECP2 duplication syndrome (OMIM #300260) [142]. This evidence concerns the gene MECP2 and atypical Rett syndrome.