NR1H3 and Huntington disease: Knockout of both LXRα and β led to impaired cholesterol homeostasis and neuronal degeneration in the brain.26 Mouse models of HD have impaired cholesterol biosynthesis.19 Interestingly, mice overexpressing wild-type huntingtin with 18 glutamines have a reversal of this phenotype with a higher activity of the cholesterol biosynthetic pathway compared to wild-type mice, suggesting that wild-type huntingtin normally plays a key role in cholesterol homeostasis.