Henoch-Schönlein purpura (HSP) is a multifactorial inflammatory disease whose pathogenesis remains unknown. Pyrin encoded by the MEFV gene (NM_000243; OMIM 608107) is an important active member of the inflammasome and has been shown to affect the expression of many of the genes involved in immune and inflammatory responses. The aim of our study was to elucidate the possible roles of MEFV genetic variants on the susceptibility to HSP and its clinical outcomes in 78 patients with HSP and 189 controls in China. A significant association was found between the E148Q polymorphism (G->C) and HSP susceptibility (odds ratio 2.76, 95% confidence interval 1.76-4.34, P=0.0001). The C allele of E148Q was associated with joint involvement (P=0.014) but not with HSP nephritis (P=0.1). The clinical score was higher in subjects with the CC genotype than in those with the CG or GG genotype (4.13+/-3.53 vs. 1.94+/-1.70, respectively; P=0.011). P369S was not associated with HSP or other phenotypes. M694V and M680I were absent in our patients. Our results suggest that MEFV E148Q could be a contributory genetic factor to HSP and HSP-related joint syndromes.