The Effect of Positive Family History of Autoimmunity in Juvenile Idiopathic Arthritis Characteristics; a Case Control Study

Objective To compare Juvenile Idiopathic Arthritis (JIA) patients with and without family history of autoimmune disease with respect to clinical features and laboratory data. Methods Sixteen JIA patients with family history of autoimmune disease were identified during study, 32 patients were chosen for comparative group from referred patients to the rheumatology clinic according to the date of referral. Two groups were compared with respect to age of onset, sex, subtype, disease activity, duration of active disease and laboratory variables. Findings The age of onset was significantly lower in JIA patients with family history of autoimmunity (4.7 years vs. 7.0 years; P=0.02), polyarthicular subtype was more frequent in patients with positive family history (50% vs.25%; P=0.04) most of JIA patients with positive family history were in the active phase at the time of study (64% vs 25%; P=0.02) and had a longer duration of active disease (21.0 months vs 12.3 months; P=0.04). Patients with positive family history had more positive ANA (43.5%% vs 12.5%; P=0.01) and also more positive ADA (75% vs 20.8%; P=0.002). Two groups were similar according to sex, and other laboratory variables. Conclusion JIA patients with family history of autoimmune disease seem to have a more severe disease than patients without such family history, they are younger at the onset, and have mostly poyarthicular subtype. They also have more ANA and ADA positivity. These findings are different from familial JIA case-control studies according to active disease duration, subtype, and ANA positivity.