XRCC1 and cerebellar ataxia: Examples of the latter are individuals with spinocerebellar ataxia with axonal neuropathy 1 (SCAN1), ataxia with oculomotor apraxia type 1 (AOA1), and ataxia with oculomotor apraxia-XRCC1 (AOA-XRCC1), in which the DNA strand break repair proteins TDP1, aprataxin, and XRCC1 are mutated, respectively (7–10).