CYBB and chronic granulomatous disease: CGD is characterized by inherited defects in the innate immune system resulting from mutations in the genes encoding any of the five components of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex, including gp91-phox, p22-phox, p40-phox, p47-phox, and p67-phox [1, 2].