Kawasaki disease can be difficult to diagnose in infants, putting them at higher risk for developing coronary artery dilatation. It can be even more difficult to diagnose in the setting of preexisting cardiac anomalies such as those found in Williams syndrome. We present a case of a three-month-old male with Williams syndrome with rapidly developing giant coronary aneurysms due to Kawasaki disease. This case demonstrates the importance of repeat echocardiography in diagnosing incomplete Kawasaki disease in infants. We speculate that elastin changes, as present in Williams syndrome, may put affected children at higher risk for development of giant coronary arteries should they acquire Kawasaki disease.
Keywords: Kawasaki disease; Williams syndrome; coronary artery aneurysm; pediatrics.