CGD is characterized by impaired production of reactive oxygen species and mutations in one of the following genes CYBB, CYBA, NCF1, NCF2, NCF4, CYBC1/EROS, which are the causes of the low levels of H2O2 production cells necessary for protection against mycobacterial infections (4, 15, 20). This evidence concerns the gene CYBA and chronic granulomatous disease.