PNKP and Spinocerebellar ataxia type 3: Alterations in PNKP expression levels in humans have also been linked to the pathogenesis of spinocerebellar ataxia type 3 (SCA3) in combination with mutant Ataxin-3 (ATXN3) (Chatterjee et al, 2015; Gao et al, 2015).