Defects in NOD2 are the cause of sarcoidosis early-onset (EOS) . EOS is a form of sarcoidosis manifesting in children younger than 4 years of age. Sarcoidosis is an idiopathic, systemic, inflammatory disease characterized by the formation of immune granulomas in involved organs. Granulomas predominantly invade the lungs and the lymphatic system, but also skin, liver, spleen, eyes and other organs may be involved. Early-onset sarcoidosis is quite rare and has a distinct triad of skin, joint and eye disorders, without apparent pulmonary involvement. Compared with an asymptomatic and sometimes naturally disappearing course of the disease in older children, early-onset sarcoidosis is progressive and in many cases causes severe complications, such as blindness, joint destruction and visceral involvement.
