IDO2 and Alzheimer disease: While EIF4EBP1 and FGFR1 are involved in the PI3K-Akt signaling pathway, which does play a role in regulating immune cell effector functions through various mechanisms [49], a more likely candidate gene for AD susceptibility would be indoleamine 2,3-dioxygenase 2 (IDO2), one of two neighboring genes involved in tryptophan catabolism and modulation of immune responses.