Chronic Granulomatous Disease is a rare form of primary immunodeficiency, characterized by the appearance of granulomas (inflammatory lesions) and by a greater susceptibility to infectious phenomena. It can manifest itself from the first years of life with recurrent fungal and bacterial infections, especially affecting the lymph nodes, lungs, gastrointestinal and genitourinary tracts (but any part of the body can be affected), causing a granulomatous evolution of the locally affected areas , which can lead to organ and tissue damage. At the base of its pathogenetic mechanism is the malfunction of phagocytes, particular types of white blood cells, responsible for the incorporation and destruction of pathogenic organisms through the production of reactive oxygen species (the enzymatic complex responsible for this form of immunity is called NADPH oxidase). If this mechanism is faulty, the phagocytes will no longer be able to kill the pathogens: this will lead to the formation of granulomas (nodules of an inflammatory nature, in this case of infectious origin) filled with cells of the immune system, with the purpose of isolating the pathogen from healthy tissue. Several genes involved in the genesis of Chronic Granulomatous Disease have been identified. Among these, CYBA, CYBB, NCF1, NCF2, and NCF4 appear to be the most important and responsible for the autosomal recessive forms, while the X-linked form is linked to the CYBB gene. In cases where the disease is not related to any gene mutation, the causes remain unknown.