Chronic Granulomatous Disease (CGD)

Chronic Granulomatous Disease (CGD) is a rare inherited disorder that affects the body's immune system, specifically the ability of certain white blood cells to kill bacteria and fungi. This condition primarily involves the phagocytes, which are cells that normally engulf and destroy harmful microbes. In people with CGD, these cells cannot produce the necessary reactive oxygen species to kill some types of bacteria and fungi, leading to frequent and severe infections. The disease mainly affects the lungs, skin, lymph nodes, and liver, causing persistent infections and inflammation. Over time, the body forms granulomas, which are clusters of immune cells that try to wall off the infections but can cause tissue damage. This condition usually presents in childhood but can be diagnosed at any age.

Chronic Granulomatous Disease (CGD) is a primary immunodeficiency characterized by a defect in the NADPH oxidase complex of phagocytes, leading to impaired production of reactive oxygen species (ROS) necessary for intracellular killing of catalase-positive organisms. The most common cause is mutations in genes encoding components of the NADPH oxidase, such as CYBB (encoding gp91^phox), resulting in X-linked inheritance, or autosomal recessive mutations in CYBA, NCF1, NCF2, or NCF4. This defect results in recurrent, life-threatening infections with organisms like Staphylococcus aureus, Serratia marcescens, Burkholderia cepacia, Nocardia, and Aspergillus species. The hallmark of the disease is the formation of granulomas due to chronic inflammation and inability to clear infections. Clinical manifestations include recurrent pneumonia, abscesses, lymphadenitis, and osteomyelitis. Diagnosis and management are critical to prevent severe complications and improve survival.