NCF4 (Neutrophil Cytosolic Factor 4): NCF4 is a gene that encodes a component of the NADPH oxidase complex, which plays a crucial role in immune defense against pathogens. It helps produce reactive oxygen species in phagocytes, which are essential for killing microbes. Mutations in NCF4 have been associated with chronic granulomatous disease, a disorder characterized by recurrent bacterial and fungal infections.