Chronic granulomatous disease is a hereditary disorder of the immune system. In this disorder, phagocytes, a type of white blood cell, do not function properly. Normal phagocytes ingest and then kill microorganisms invading the body. In chronic granulomatous disease, the phagocytes can ingest invaders but cannot kill them. They lack the ability to produce certain substances that normally enable them to kill. When does chronic granulomatous disease typically first appear?