NCF4 and Alzheimer disease: Also, both the NOX enzyme activity level and protein levels of the different subunits (p67phox, p47phox, and p40phox) were reported to be elevated in the brains of patients with AD (Ansari and Scheff, 2011) and AD transgenic mice in correlation with a cognitive decline (Park et al., 2008; Bruce-Keller et al., 2011; Han et al., 2015; Lin et al., 2016).