ATXN2 and cerebellar ataxia: However, we have termed a subset of ataxias, not just with reduced IP3R1 but also with supersensitive IP3R1, and regardless of the mutated gene (e.g., ITPR1, Ataxin-1, Ataxin-2, Ataxin-3) as ‘IP3R1-associated ataxias’ [32].