Astrocyte expressing HSD3B7 is responsible for degradation of oxysterol, the active oxidized product of cholesterol, which can be used as a marker of brain atrophy in patients holding aging neurons with AD and HD (Leoni & Caccia, 2011; Rutkowska, Preuss, Gessier, Sailer, & Dev, 2015). Here, HSD3B7 is linked to Brain atrophy.