BDNF and Alzheimer disease: Interestingly, children with severe autism and aggression over-express the AD-relevant beta-amyloid precursor protein (βAPP) at two or more times the levels of children without autism and up to four times more than children with mild autism; βAPP-derived Aβ peptides can directly inhibit the proteolytic conversion of BDNF from pro-BDNF thus reducing its levels (Sokol et al., 2006; Tanila, 2017).