This project is an important first step in our ability to use genetic information to guide how we monitor and treat juvenile idiopathic arthritis. In this study, we will examine 3 genetic variants associated with JIA and whose biological effects we have characterized. We will determine whether these genetic variants are associated with particular clinical features in JIA. If we are successful, this project will be the start of an ambitious second phase aimed to link genetic information to patient outcomes across the CARRA network.