It has been found that human APOE4 carriers with Alzheimer’s disease (AD) have lower levels of BDNF in their serum32 than APOE3 carriers, and that APOE4 carriers with mild cognitively impairment have dampened BDNF increase after exercise compared to APOE3 carriers33. This evidence concerns the gene BDNF and early-onset autosomal dominant Alzheimer disease.