Importantly, MECP2‐deficient cells, including fibroblasts from RTT patients, are characterized by the upregulation of HDAC6 and, consequently, reduced acetylation of polymerized α‐tubulin and microtubule instability (Delépine et al, 2013, 2016; Gold et al, 2015). Here, HDAC6 is linked to Rett syndrome.