NTRK2 and early-onset autosomal dominant Alzheimer disease: The high-affinity receptor of BDNF, tropomyosin-related kinase B (TrkB), can be auto-phosphorylated after BDNF binding to TrkB, which subsequently activates several intracellular signaling pathways exerting neuroprotective effects against cerebral ischemic injury, epilepsy, Alzheimer’s disease and so on (Han et al., 2011; Yang et al., 2018).