Deep phenotyping and neuropathological studies in Sacs−/− transgenic mice have shown pathological changes in the synaptic compartment, electric impairment of Purkinje cells (PCs) with significant neuronal cell loss in the cerebellum, as well as motor deficits reminiscent of ataxia, all features that replicate those seen in ARSACS patients [4,8,10,11]. The gene discussed is SACS; the disease is Ataxia.