PTPRN and early-onset autosomal dominant Alzheimer disease: Tyrosine phosphatases (Ptprn and Ptprt) are associated with the breakdown of intracellular neurofibrillary tangles, a hallmark lesion of Alzheimer's disease, while ionotropic glutamate receptor (Gria3) plays an integral role in synaptogenesis and the formation of neuronal circuitry.39 Both of these types of genes (Ptprn, Ptprt, and Gria3) were up-regulated by OPP.