In all subjects, serum proBDNF levels were significantly higher (p < 0.0001) in AD patients (mean ± SD = 4140.94 ± 665.11 pg/ml) than in HCs (mean ± SD =2606.94 ± 1267.78 pg/ml), whereas there was no significant difference in serum mBDNF levels (p = 0.063). The gene discussed is BDNF; the disease is Alzheimer disease.