Preclinical studies of AD also support this notion: FMT treatment of APPswe/PS1dE9 transgenic mice showed improvement in AD-like pathology (decreased phosphorylation of tau protein and the levels of Aβ40 and Aβ42) [116], whereas FMT treatment in 5xFAD mice reduced amyloid plaque burden in the brain and improved cognition [117]. This evidence concerns the gene MAPT and Alzheimer disease.