In a study by Chen and colleagues, transgenic APP/PS1 mice, a model bearing the mutations in transgenes for APP and PSEN1 resulting in Aβ plaque deposition, demonstrated altered microbiota preceding amyloidosis and microgliosis, suggesting a role of the gut microbiota in AD pathogenesis (Table 1, [72]). The gene discussed is PSEN1; the disease is Alzheimer disease.