TrkB decreased in the hippocampus and cerebral cortex early in the progression of AD (Schindowski et al., 2008; Zuccato and Cattaneo, 2009), and has a role in the pathogenesis of AD (Minichiello, 2009; Nagahara et al., 2009; Devi and Ohno, 2012). Here, NTRK2 is linked to Alzheimer disease.