Juvenile idiopathic arthritis (JIA) is a non-common disease in children that can persist into adulthood. JIA is considered to be an auto-immune disease. Genetic factors play a role in the... Show moreJuvenile idiopathic arthritis (JIA) is a non-common disease in children that can persist into adulthood. JIA is considered to be an auto-immune disease. Genetic factors play a role in the pathogenesis. In a new cohort of JIA patients from North-West European descent genetic candidate gene association studies have been performed. In this cohort we have discovered new associations with the susceptibility of JIA and the genes/loci TRAF1/C5, 4q27, CD226 and CD28. These genes have already been associated with other auto-immune diseases and might be part of a shared common auto-immune susceptibility. Also genetic association with the course of disease has been studied, revealing an association of VTCN1 and the severity of JIA defined by the percentage of active disease in the first two years. VTCN1 encodes B7-H4 that is involved in the co-stimulation of T-cells and inhibits the immune-response. Until the precise role of VTCN1 will be clarified, the genetic association might be of use in predicting the course of disease and might be a lead point for new treatment. Show less