MPO and juvenile idiopathic arthritis: Systemic inflammatory and autoimmune disorders, including juvenile idiopathic arthritis, Behçet disease, Vogt–Koyanagi–Harada syndrome, and inflammatory bowel disease–associated uveitis, were considered but ultimately deemed unlikely given normal immunologic markers (ANA, ANCA, MPO, PR3, IgG, IgM, IgA, IgE) and the absence of systemic manifestations such as arthritis, mucocutaneous lesions, gastrointestinal symptoms, or neurological involvement [4, 5].