X-linked chronic granulomatous disease (X-CGD) is a rare genetic disorder, which affects
boys. It is a primary immunodeficiency disorder which results from an inability of the white
blood cells called phagocytic cells (or phagocytes) to kill invading bacteria and fungi.
These cells have difficulty forming the free radicals (most importantly the superoxide
radical due to defective phagocyte NADPH oxidase complex) which are important in the killing
of ingested pathogens. In X-CGD (which accounts for two thirds of CGD patients), the defect
lies in a gene which makes up a critical part of the NADPH-oxidase complex (the catalytic
subunit; gp91-phox protein). Therefore they kill bacteria and fungi poorly, and the patients
suffer from severe and recurrent infections. This also results in inflammation which can
damage parts of the body such as the lung and gut.
In many cases, patients can be adequately protected from infection by constant intake of
antibiotics. However, in others, severe life-threatening infections break through. In some
cases, inflammation in the bowel or urinary systems results in blockages which cannot be
treated with antibiotics, and which may require the use of other drugs such as steroids.
Development of curative treatments for CGD is therefore of great importance.