TNFRSF1A and adult-onset Still disease: For known hereditary periodic fever syndrome genes, a previous study showed that association with 3 rare variants in the Mediterranean fever (MEFV) gene, which encodes pyrin, and mutations in the tumor necrosis factor receptor superfamily member 1A (TNFRSF1A) gene were significant and that these genetic factors were associated with a severe disease course of AOSD (17).