CatE was barely detectable in the cortex of wild‐type (WT) mice at 2, 6 and 10 months of age (Figure 1a‐c), however, both mRNA and protein expression of CatE increased significantly in the cortex of AD mice at 6‐ and 10‐months of age compared with age‐matched WT mice (Figure 1a‐c). This evidence concerns the gene CTSE and Alzheimer disease.