PTPN5 and Alzheimer disease: STriatal-Enriched protein tyrosine Phosphatase is an intracellular phosphatase, enriched in the CNS except in the cerebellum, that is encoded by the PTPN5 gene, and is a member of a family of over a hundred protein tyrosine phosphatases (PTPs) (Lombroso et al., 1991, 1993), and it is one of the targets via which Aβ exerts its deleterious effects in AD.