FMR1 and fragile X-associated tremor/ataxia syndrome: Our team was the first to report mitochondrial dysfunction as a common feature in biological samples including primary skin fibroblasts, peripheral blood monocytic cells (PBMCs), serum/plasma and postmortem brain tissues from carriers of the FMR1 premutation (defined as a moderate (55–200) CGG repeat expansion in the FMR1 gene) with and without FXTAS [23,24,44,45,46] as well as in murine models of the premutation [47].