A downregulation of Cyp11a1 and Scarb1 in the cortex and Sc4mol in both striatum and cortex were reported in HD knock-in mice [73], decreased expression levels of Hmgcs1 and Sc4mol were found in the striatum of R6/2 mice with 150 CAG repeats [74], and a trend toward downregulation of Hmgcs1 was observed in the striatum of BACHD rats [75]. This evidence concerns the gene MSMO1 and Huntington disease.