Lysosomal (leucocyte) proteinase and sulfatase levels in Dyggve-Melchior-Clausen (DMC) syndrome

Abstract

Patients with the DMC syndrome have been suggested to possess a specific sulfatase abnormality and/or to be deficient in a proteinase cleaving glycoprotein-acid mucopolysaccharide (AMP) linkage. We have previously found in DMC patients an abnormal excretion of urinary AMPs of which hyaluronic acid and chondroitin sulfate (A + C) were oversulfated and keratosulfate and heparan sulfate were undersulfated. Lysosomal acid proteinase, i.e. cathepsin D (EC 3.4.23.5) and neutral proteinase : elastase (EC 3.4.21.11) and cathepsin G were found to be normal in DMC patients. However, alpha 2-macroglobulin in serum was raised. This increase may be associated with a complex formation of alpha 2-macroglobulin with a neutral proteinase released from the cells. Increased levels of chondroitin sulfate N-acetylgalactosamine-6-sulfate sulfatase and sulfamidase and decreased enzymic levels of arylsulfatase A and B (EC 3.1.6.1) were found in leucocytes of DMC patients. The sulfatase activities assayed in the present study support our theory that a specific sulfatase abnormality may exist in the DMC syndrome.