These results, together with the well‐recognized association of cerebellar dysfunctions with autistic‐like behaviors and ataxia (Tsai et al, 2018), prompt a detailed description of the development of Mecp2 null cerebellum and whether Mecp2 null brains manifest alterations in cortico‐cerebellar motor circuitries. Here, MECP2 is linked to cerebellar ataxia.