Juvenile idiopathic arthritis in DiGeorge syndrome: a case report and literature review.

INTRODUCTION: DiGeorge syndrome (DGS) is an inborn error of immunity characterized by wide phenotypic variability, with a broad spectrum of autoimmune manifestations, including autoimmune cytopenias, thyroiditis, and juvenile idiopathic arthritis (JIA). However, the clinical features of JIA in DGS are not fully understood. Here, we report a case of DGS with JIA and provide a comprehensive review to facilitate early diagnosis and management. CASE DESCRIPTION: A 22-month-old girl had a history of frequent respiratory infections and delayed speech after birth. She also had dysmorphic facial features and developmental delay. She had undergone repair of a ventricular septal defect at 3 months of age, during which the thymus was not visualized. Genetic testing revealed a partial heterozygous deletion of 22q11.2. She presented with inflammatory polyarthritis involving bilateral knees and the left hand for 5 months. Antinuclear antibody (ANA) was positive with a titer of 1:320. Anti-cyclic citrullinated peptide antibody showed weakly positive. Magnetic resonance imaging showed synovitis of the affected joints. The patient experienced frequent respiratory infections and delayed speech after birth. Gene examination showed a partial heterozygous deletion of 22q11.2. Thus, she was diagnosed as DGS with JIA. Etanercept was initiated after 4 months of ineffective treatment with naproxen and methotrexate, and remission was observed after 6 months of treatment. Literature review showed a female predominance (62.7%, 32/51) in this population; 80.4% (41/51) were diagnosed before 6 years of age and 62.7% (32/51) had polyarticular involvement. Moreover, 54.2% (26/48) were positive for ANA. Tumor necrosis factor inhibitors (TNFis), mainly etanercept or adalimumab, were used in 20 cases, with more than half of patients responding well to biologics. CONCLUSION: The disease has an early onset and polyarthritis is the most common type. Clinicians should suspect underlying DGS in a child presenting with JIA when accompanied by dysmorphic facial features, recurrent infections, congenital heart disease, hypoparathyroidism with hypocalcemia and hyperphosphatemia, and/or decreased T-cell subsets. Treatment with TNFi should be considered when non-steroidal anti-inflammatory drugs and methotrexate are ineffective. Furthermore, follow-up is essential for monitoring adverse drug reactions and proposing prompt intervention.