CYP46A1 and Spinocerebellar ataxia type 3: Cholesterol 24S-hydroxylase (CYP46A1), the rate-limiting enzyme in cholesterol degradation, was reduced in cerebellar extracts from SCA3 patients and in SCA3 mice, whereas AAV-mediated overexpression of CYP46A1 protected cerebellar PCs, reduced ataxin-3 protein aggregation, and improved autophagy [49].