MeCP2 induces the clustering of heterochromatin in a concentration-dependent manner35, and changes in its levels or mutations in the MeCP2 gene are linked to diseases, with special relevance to the neurological disorder Rett syndrome (OMIM: #312,750)36–38, as MeCP2 is especially abundant in neurons39,40. The gene discussed is MECP2; the disease is atypical Rett syndrome.