X-linked CGD (X-CGD) results from mutations in the CYBB gene encoding the gp91phox subunit (about 70% of patients), while autosomal recessive (AR) CGD is associated with mutations in one of the CYBA, NCF1, NCF2, and NCF4 genes encoding for p22phox, p47phox, p67phox, and p40phox respectively. Here, NCF1 is linked to chronic granulomatous disease.