Knee Joint Swelling at Presentation: A Case of Pediatric Crohn Disease With a TNFAIP3 Mutation

Abstract

Crohn disease (CD) is a chronic inflammatory disease, and its incidence in children is rising. Despite extensive reports and investigations, the pathogenesis of CD has not been clearly elucidated, particularly in regard to triggering factors. A genetic predisposition is considered important when investigating the mechanism leading to CD, and the discovery of new CDassociated genes has increased our understanding of its immunopathogenesis and improved the efficacy of its treatment of CD. Early detection and treatment (eg, as children) with gene-based precision therapy can effectively prevent complications related to CD. In this case, a Chinese Han boy with CD associated with a mutation of tumor necrosis factor a-induced protein 3 was treated with recombinant human tumor necrosis factor-a receptor II:IgG Fc fusion protein. We suspected the boy had CD because of chronic abdominal pain, aphthous stomatitis, moderate anemia, a high erythrocyte sedimentation rate (36-79 mm/h), multiple intestinal ulcers, knee joint swelling, and a tumor necrosis factor a-induced protein 3 mutation. After total enteral nutrition and hormone therapy for 5 months, his abdominal pain and joint symptoms did not improve, so we started gene-based precision therapy with recombinant human tumor necrosis factor-a receptor II: IgG Fc fusion protein, which may play an important role in restricting TNF-a-induced NF-kB signaling. After 3 weeks, inflammation indicators were within the normal range, and multiple ulcers and joint symptoms were relieved. The present case demonstrates a safe therapeutic schedule that leads to rapid improvements in the clinical and biochemical status of patients with CD.