Six patients with chronic granulomatous disease (CGD) were registered, 83.33% (n = 5) of whom had a proven genetic defect, with disease-causing variants in CYBB gene encoding the GP91-phox protein accounting for 3 cases; disease-causing variants in CYBA gene encoding P22-phox protein (n = 1) and in NCF1 gene encoding P47-phox (n = 1) accounted for the remaining cases. The gene discussed is CYBB; the disease is chronic granulomatous disease.