NPTX2 and Alzheimer disease: Moreover, Goetzl et al. found that NDE levels of several functionally specialized synaptic proteins—neuronal pentraxin 2 (NPTX2), neurexin 2α (NRXN2α), AMPA4-containing glutamate receptor (AMPA4), and neuroligin 1 (NLGN1)—decline progressively with AD advancement and cognitive loss [67].