MECP2 and Rett syndrome: Our study found that studying other human tissues, such as fibroblasts, can reflect the same dysregulations caused by loss of function of MECP2. However, integrating all knowledge is complicated by the heterogeneity in experiments and tissue-specific effects of MECP2. Dysregulation of various cellular functions was identified, including cytoskeletal organisation, vesicular activity, translation and mRNA processing, which are altered in patients with RTT, RTT-like phenotypes and MDS.