Thus far, 11 PDE families have been described, most of them are expressed in the brain, attracting attention as a source of new targets for the treatment of psychiatric and neurodegenerative disorders.22,23 PDE III, PDE IV, or PDE V inhibitors have been shown to have positive effects on the pathology and behavior in several animal models of AD22–25 and human studies of AD patients.26,27 Most of these studies were based on the perspective of neuronal/synaptic and glial dysfunction, and impairment of neurogenesis and synaptic resilience in AD models and patients. The gene discussed is ALDH7A1; the disease is Alzheimer disease.