The cAMP and cGMP dual-substrate specific PDE2A enzyme is abundantly expressed in the brain, particularly in structures of the limbic system [12,13], indicating an important role in the pathophysiology of neurodegenerative and neuropsychiatric diseases like Alzheimer’s disease, schizophrenia and dementia [14,15]. Here, PDE2A is linked to early-onset autosomal dominant Alzheimer disease.