However, most of these TNR expansion diseases share a common feature, ataxia with prominent cerebellar degeneration in clinical, whereas DNA damage response and DNA repair aberrance in genetic, especially the Huntington's disease (HD) and multiple spinocerebellar ataxias (SCAs) (Martins et al., 2014; Lee et al., 2015; Bettencourt et al., 2016). The gene discussed is TNR; the disease is Huntington disease.