Mucopolysaccharidosis type I (MPS I) results from deficiency of the lysosomal enzyme alpha-L iduronidase. Three subtypes, based on severity of clinical findings, have been described, of which MPS type IS (also called Scheie syndrome) is the mildest form. A woman (age, 30 years) and her little brother (age, 21 years) presented to our clinic complaining of atrophy of the thenar muscles, numbness in both hands, and contractures in the finger joints. Electrophysiologic examination showed severe carpal tunnel syndrome for both patients. Findings of cardiac and ocular involvements and decreased level of alpha-L iduronidase confirmed the diagnosis of Scheie syndrome. Enzyme replacement therapy was initiated for the further prevention of musculoskeletal and other organ complications. Delayed diagnosis of MPS type-IS and the musculoskeletal findings are discussed in these 2 familial patients.