The present study was designed to examine the relationship between the onset of cognitive deficiencies and colonic dysmotility/inflammation, enteric depositions of AD-related proteins (Aβ, tau, p-tau, α-synuclein (α-syn) and their heterocomplexes) in the prodromal phases of AD in the SAMP8 spontaneous AD model. This evidence concerns the gene SNCA and Alzheimer disease.