Moreover, serum BDNF levels fall significantly in progressive cognitive decline, e.g., mild cognitive impairment (Yu et al., 2008), Alzheimer’s disease (Gunstad et al., 2008), Huntington’s disease (Ciammola et al., 2007), and schizophrenia (Zhang et al., 2012). The gene discussed is BDNF; the disease is Cognitive impairment.