Comparison of clinical and laboratory variables in familial versus sporadic systemic onset juvenile idiopathic arthritis
To compare patients with familial versus sporadic juvenile idiopathic arthritis (JIA) with respect to clinical and laboratory variables. The familial JIA group comprised 11 affected siblings belonging to 4 families, while the comparative group comprised 22 patients selected by systematic sampling from JIA patients presenting to our pediatric rheumatology clinic; the first patient was chosen randomly and the subsequent patients chosen at intervals of 3. The 2 groups were compared with respect to demographic information, age at onset of disease, disease activity, disease damage, and laboratory variables. The 2 groups were comparable with respect to age, sex, and onset type of disease. All patients from the familial group were from a southern province of Saudi Arabia (p = 0.001). The familial group had an earlier age at onset of disease (p = 0.039), the mean number of actively inflamed joints was higher (p = 0.009), and functional capacity as measured by Childhood HAQ was worse (p = 0.048), compared with the sporadic group. Other variables showed no significant differences. The comparison of patients with familial versus sporadic JIA revealed a significant difference in origin of patients and age at onset of disease. These differences may be helpful in identifying the predisposing genes in familial patients with JIA.