MECP2 and atypical Rett syndrome: In Rett syndrome, an X-linked chromatinopathy caused by heterozygous mutations in the gene MECP2, researchers discovered alternative splicing of the MECP2 transcript led to the production of a novel isoforms with different N-terminus relative to the canonical MECP2 transcript (Kriaucionis and Bird 2004; Mnatzakanian et al. 2004).