Djelti et al. [65] have shown that in the APP mouse model of AD the abundance of amyloid-β peptides increased following inhibition of Cyp46a1 expression via AAV delivery of short hairpin (sh) RNA directed against mouse Cyp46a1 to the hippocampus and that following treatment neuronal death was more widespread in these mice than in normal mice. This evidence concerns the gene CYP46A1 and Alzheimer disease.