CYP46A1 and Huntington disease: In order to study the regulation of genes involved in cholesterol metabolism in HD mice after virus-driven CYP46A1 expression, bilateral stereotaxic injection of AAVrh10-GFP (control) and AAVrh10-CYP46A1-HA (a human version of CYP46A1 with a haemagglutinin (HA) tag) was performed in the striatum of four-month-old mice.