The proband previously underwent metabolic profiling (blood amino acids/acylcarnitines, urinary organic acids), DNA testing for repeat expansion ataxias (FXN, ATXN1, ATXN2, ATXN3), and gene panel sequencing to search for variants in genes associated with hereditary motor–sensory neuropathies and diseases with similar phenotypes. Here, ATXN3 is linked to cerebellar ataxia.