MECP2 and atypical Rett syndrome: Interestingly, Rett syndrome, a genetic neurodevelopmental disorder with mutations in the X-chromosomal MECP2 (methyl-CpG-binding protein 2) gene, affecting mostly girls, is inflicted with multiple mitochondrial dysfunctions, including brain-region specific (neocortex) reduction in 14-3-3 protein theta [86].