Sly syndrome /slī/ [William S. Sly, American physician, b. 1932] , a mucopolysaccharidosis caused by deficiency of an enzyme important for the degradation of various mucopolysaccharides. It is characterized by excretion of mucopolysaccharides in the urine and by granular inclusions in granulocytes. Onset is between 1 and 2 years of age, with mild to moderate Hurler-like features, including dysostosis multiplex, pigeon breast, organomegaly, cardiac murmurs, short stature, and moderate cognitive impairment. Milder forms exist. Also called mucopolysaccharidosis.
