Tehran University of Medical Sciences The Research in Heart Yield and Translational Medicine (RHYTHM) 3115-7270 18 3 2023 07 30 224 227 EN Mogtaba Gorji Department of Pediatric Cardiology, Children’s Medical Center (Pediatric Center of Excellence), Tehran University of Medical Sciences, Tehran, Iran Maryam Taraz Department of Pediatric Cardiology, Tehran University of Medical Sciences, Tehran, Iran. Behdad Gharib Department of Pediatric Cardiology, Tehran University of Medical Sciences, Tehran, Iran. Vahid Ziaee Pediatric Rheumatology Research Group, Rheumatology Research Center, Tehran University of Medical Sciences, Tehran, Iran. 2023 05 12 2023 11 06 Kawasaki disease is an acute self-limiting systemic vasculitis in childhood, resulting in arterial swelling or inflammation and eventually leading to cardiovascular problems, such as coronary artery aneurysms. Based on previous studies, serum sodium ≤133 mmol/L, albumin ≤3.2 g/dL, alanine transaminase ≥80 U/L, and neutrophil percentage ≥80% at diagnosis are risk factors for intravenous immunoglobulin (IVIg). However, the prevalence of resistance to Ig among children with Kawasaki disease varies among different countries due to diversity in evaluation, treatment, and diagnosis. Approximately, 10% to 20% of patients have IVIg-resistant Kawasaki disease. As the probability of coronary artery damage associated with IVIg-resistant Kawasaki disease is higher than that with IVIg-sensitive Kawasaki disease, the early detection and appropriate treatment of IVIg-resistant Kawasaki disease can decrease the probability of damage to coronary arteries and hospital lengths of stay and cost. Kawasaki disease in early infancy is uncommon, and sometimes it occurs with thrombosis and peripheral gangrene. A positive genetic background may play a role in susceptibility to thrombosis. We herein describe a patient suffering from an IVIg-resistant Kawasaki disease with severe coronary artery thrombosis and positive genetic mutation. Medical treatment resolved the thrombosis, but the coronary arteries remained dilated. https://rhythm.tums.ac.ir/index.php/jthc/article/view/1856 https://rhythm.tums.ac.ir/index.php/jthc/article/download/1856/1076