Mutations that cause CGD are found in CYBB and CYBA, which encode the membrane-bound NADPH oxidase components Nox2/gp91phox and p22phox, and NCF1, NCF2, and NCF4, which encode the cytosolic regulatory factors p47phox, p67phox, and p40phox, respectively (Figure 1) (O'Neill et al., 2015). The gene discussed is CYBB; the disease is chronic granulomatous disease.