Characterization of these disorders has primarily focused on familial forms of disease due to highly penetrant mutations as was the case with the identification of the MEFV gene responsible for Familial Mediterranean Fever (FMF) and mutations in the TNFRSF1A gene as the cause of dominantly inherited TRAPS (Tumor Necrosis Factor Receptor Associated Periodic Syndrome). The gene discussed is MEFV; the disease is familial Mediterranean fever.