Interestingly, additional CYP46A1 expression in non-neuronal cells (astrocytes) was documented in the AD- and HD-affected brains, perhaps to compensate for CYP46A1 loss in neurons due to neurodegeneration (Bogdanovic et al., 2001; Brown et al., 2004). The gene discussed is CYP46A1; the disease is Alzheimer disease.