Additionally, Samaco et al. [37] demonstrated differences in MeCP2 expression levels in autism, pervasive developmental disorder, Prader-Willi syndrome, and Angelman syndrome; by laser-scanning cytometry, the disturbances in MeCP2 expression were determined as due to differential transcriptional and post-transcriptional mechanisms. This evidence concerns the gene MECP2 and Rare pervasive developmental disorder.