Inborn errors of immunity (IEIs) have a wide range of manifestations, chronic granulomatous disease (CGD) represents the classic disorder of phagocytosis due to a deficiency in one of the subunits (GP91Phox, P47Phox, P40Phox, P67Phox, P22Phox) of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex deficiency where the phagocytes lose their ability to kill certain catalase positive pathogens like bacteria and fungi leading to recurrent life-threatening infections and granuloma formation [1]. The gene discussed is CAT; the disease is chronic granulomatous disease.