A 21-MONTH-OLD boy was referred to our hospital for evaluation of hydrocephalus and unusual facies. A diagnosis of Hurler syndrome was established on the basis of deficient leukocyte α-L-iduronidase enzyme activity, elevated urinary excretion of glycosaminoglycans, and clinical features. The upper extremity blood pressure at initial evaluation was 90/42 mm Hg, and findings from cardiac auscultation revealed a grade II to III/VI pansystolic murmur heard at the cardiac apex. The liver was enlarged. Pulses were equal to palpation in the upper and lower extremities. A 2-dimensional (D) cardiac sonogram showed thickening of the mitral valve with mild mitral regurgitation, concentric left ventricular hypertrophy, and a normal shortening fraction.