The main differential diagnoses for CGD are disorders of recurrent severe or atypical infection, granulomas and hyperinflammation [107], including cystic fibrosis, severe G6PD deficiency [54], glutathione synthetase deficiency [58], protein kinase C delta deficiency [123,124], leukocyte adhesion deficiency [54], combined or common variable immunodeficiency [91], MyD88/IRAK4 deficiency, hyper-IgE syndrome [125], allergic bronchopulmonary aspergillosis, sarcoidosis, IBD, MPO deficiency [54] and SAPHO syndrome (synovitis, acne, pustulosis, hyperostosis, osteitis). The gene discussed is MPO; the disease is chronic granulomatous disease.