Calpain activation (Adamec et al, 2002) and TrkB‐FL loss (Allen et al, 1999; Ferrer et al, 1999) had been observed before in the brain of AD patients, while a TrkB‐FL calpain processing site was mapped by Edman sequencing in neurons treated with Aβ (Jeronimo‐Santos et al, 2015). Here, NTRK2 is linked to Alzheimer disease.