TNFRSF1A and TNF receptor 1-associated periodic fever syndrome: Several pathogenetic mechanisms have been studied in vitro to demonstrate how TNFRSF1A mutations contribute to the development of the TRAPS phenotype: (i) impaired TNFRSF1A cell surface expression; (ii) altered TNF-α binding; (iii) defective shedding of the receptor; and (iv) intracellular accumulation of mutated TNFRSF1A proteins [76–81].