ABCG2 and Alzheimer disease: In early onset AD patients (Fig. 1B), the results also showed a significant increase for the RBC membrane expression of GLUT1 and INSR, whereas we did not find significant alterations in the RBC membrane expression levels for ABCA1, ABCG2, PMCA, and ABCB6 between the early onset AD patients and the age-matched controls.