Your immune system plays an important function in your health—it protects you against viruses, bacteria, and other toxins that can cause disease. In autoinflammatory diseases, however, the immune system goes awry, causing unprovoked and dangerous inflammation. Now, researchers from the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), part of the National Institutes of Health, and other institutions have discovered a new autoinflammatory syndrome, a rare genetic condition that affects children around the time of birth. The findings appear in the current issue of the New England Journal of Medicine.