Pauciarticular chronic arthritis is a form juvenile arthritis affecting children ages 16 and younger. It is the most common subgroup of juvenile idiopathic arthritis, also know as juvenile rheumatoid arthritis, constituting about 50 percent of the cases. Pauciarticular chronic arthritis affects typically four or fewer joints, mostly larger joints such as knees, ankles or wrists, and often only affects a joint on one side of the body. Pauciarticular chronic arthritis can also cause eye inflammation (uveitis), seen most frequently in young girls with positive anti-nuclear antibodies (ANA). The onset of the disease is more common in children ages 2 and 3. It is less common over 5 years of age and rarely begins after age 10.