Allelic mutations in the mucopolysaccharidoses

Recognition of iduronidase deficiency as the specific defect in the Hurler and Scheie syndromes led to the discovery of a number of cases with a variety of intermediate phenotypes who also lacked iduronidase and were postulated to represent compound Hurler Scheie heterozygotes. The authors have demonstrated a selective deficiency of α L iduronidase in a patient who was previously reported as an example of chondroitin 4 sulfate mucopolysaccharidosis. Another patient with an unusual late onset, mild form of mucopolysaccharidosis was found to have a selective deficiency of arylsulfatase B, the enzyme whose activity is deficient in the Maroteaux Lamy syndrome. These individuals appear to have allelic mutations at the Hurler Scheie and Maroteaux Lamy loci, respectively.