In the brain of AD patients, it was found that both BDNF mRNA and protein levels are reduced in hippocampus and temporal cortex101, 102 while protein levels are reduced in the hippocampus and the parietal cortex.103 Other studies have shown that the pro‐BDNF is also reduced in parietal cortex104 and in nucleus basalis of Meynert (nbM) of AD patients105 and this decrease precedes the decline in choline acetyltransferase activity.103, 106 To the best of our knowledge, there are no data on pro‐BDNF measurement in the serum or CSF of AD patients. Here, CHAT is linked to Alzheimer disease.