ABCG2 and early-onset autosomal dominant Alzheimer disease: Meanwhile, comparing stages CAR and IAR, twenty-five KOs were significantly down-regulated or up-regulated, including glycolysis/gluconeogenesis, carbon fixation in photosynthetic organisms, alzheimer’s disease, starch and sucrose metabolism, cysteine and methionine metabolism, arginine and proline metabolism, MAPK signaling pathway, ABC transporters, valine, leucine and isoleucine degradation, antigen processing and presentation, nitrogen metabolism, tryptophan metabolism and selenoamino acid metabolism (Additional file 11).