NRGN and Alzheimer disease: However, in blood exosomes, meta-analysis results from two other studies29,49 showed that compared with the healthy control subjects, the levels of blood plasma neuronally derived exosome (NDE) Ng in AD patients have an obviously decrease (SMD: −6.657 [95% CI: −10.558 to −2.755], z = 3.34, P = 0.001, Fig. 5a).