In our study, we provide direct evidence for the vital role of INPP5A in the pathogenesis of SCA17, as knockdown of Inpp5a in the cerebellum led to Purkinje cell degeneration but overexpression of Inpp5a alleviated Purkinje cell degeneration. The gene discussed is INPP5A; the disease is spinocerebellar ataxia type 17.