The classical features of Hurler's syndrome are dwarfism with grotesque skeletal deformity, ugly facies, deafness, clouding of the cornea, hepatosplenomegaly, cardiac abnormalities, limitation of joint motions, and mental retardation. Some of these features may be absent, particularly clouding of the cornea and mental retardation. The inheritance pattern is of 2 types: (1) a sex-linked trait expressed only in males and (2) an autosomal recessive expressed in both males and females. This latter inheritance pattern is more common than the former. One outstanding phenotypic difference between the 2 forms of inheritance is that the sex-linked recessive tends to be much less severe without corneal cloudiness.1 During the past decade significant investigations of the histochemistry and biochemistry of Hurler's syndrome have indicated a generalized disturbance in mucopolysaccharide metabolism. Several groups demonstrated abnormal amounts of chondroitin sulfate B and a heparin derivative in the urine of patients with Hurler's syndrome.2,3 There are