To investigate the potential role of this gene in the pathogenesis of sporadic JIA, we sequenced LACC1/FAMIN in two different groups of unrelated, sporadic patients of Spanish ancestry with (1) SoJIA (n: 23) and (2) RF-negative polyarticular JIA (n: 44). The gene discussed is LACC1; the disease is polyarticular juvenile idiopathic arthritis.