This site is part of a frame. If you arrived to this page directly, click here! TRAPS (TNF receptor-associated syndrome) Recent studies of families with dominantly inherited periodic fevers* have shown that they are caused by mutations in the extracellular domain of the 55 kD TNF receptor type 1 (TNF-R1). Up to 14 mutations have been identified in such families, all in the first two extracellular domains of TNF-R1 (see figure). * Characterized by prolonged apparently unprovoked fevers, abdominal pain, pleurisy, arthritis, myalgia, rash, conjunctivitis, periorbital edema, neutrophilia, increased acute phase proteins in the blood, and reduced levels of soluble TNF-R1. Adapted from Galon et al. Curr Opin Immunol 2000; 12: 479. T50: mutation in TRAPS patients affecting hydrogen bond. C30, C33, C52, C88: mutations in TRAPS patients affecting disulfide bonds. Click here for proposed model to explain the symptoms of TRAPS