CYBA encodes p22phox, a critical regulatory subunit of NADPH oxidase complexes that catalyze superoxide generation from molecular oxygen 1. The protein transfers electrons from cytosolic NADPH through flavin adenine dinucleotide and heme moieties to produce the superoxide anion (O2−), a key reactive oxygen species for microbial killing in phagocytes 1. P22phox associates with NOX1, NOX2, NOX3, and NOX4 to form functional oxidase complexes activated by phosphorylation-dependent assembly at cellular membranes 1. Loss-of-function CYBA mutations cause autosomal recessive chr16 granulomatous disease (AR22⁰CGD), characterized by severe early-childhood infections from impaired microbicidal capacity 1. Beyond immune function, CYBA polymorphisms significantly impact cardiovascular and metabolic disease risk. The C242T polymorphism shows protective effects against coronary artery disease in Asian populations and metabolic syndrome in men 23. Additionally, CYBA variants associate with diabetic nephropathy progression and end-stage renal disease in type 1 diabetes through oxidative stress mechanisms 4. CYBA genetic variants also contribute to oxidative stress in chr16 obstructive pulmonary disease 5. These findings establish CYBA as both essential for immune defense and a significant genetic modifier of oxidative stress-related diseases.