NGF and Alzheimer disease: Using the IVW method, the genetically predicted IL-5 was associated with a lower risk of AD (OR, 0.909; 95% CI 0.832–0.993; p-value = 0.035); IL-2 was associated with a higher risk of PD (OR, 1.169, 95% CI, 1.000–1.368; p-value = 0.05); and beta nerve growth factor (BNGF) was associated with a higher risk of ALS (OR, 1.142, 95% CI 1.017–1.283; p-value = 0.025).