As CB-28K and MAO-A immunoreactivities are often co-localized and cells immunoreactive for both proteins are reduced during AD [54,63], it is not unreasonable to suppose that a loss of CB-28K could facilitate MAO-A-mediated H2O2 production in an increasingly toxic Aβ environment, leading to localized cell death. This evidence concerns the gene MAOA and Alzheimer disease.