A sensitive procedure for the diagnosis of N-acetyl-galactosamine-6-sulfate sulfatase deficiency in classical Morquio's disease

Clin Chim Acta. 1978 Aug 15;88(1):111-9. doi: 10.1016/0009-8981(78)90157-2.


The trisaccharide 6-sulfo-N-acetylgalactosamine-glucuronic acid-6-sulfo-N-acetyl-[1-3H]galactosaminitol was used as a substrate for the determination of N-acetylgalactosamine-6-sulfate sulfatase activity. The amount of liberated sulfate was measured indirectly by separating monosulfated reaction products from the substrate on Dowex 1 X 2 microcolumns in a simple two step procedure. Fibroblast homogenates from patients with various genotypes, except classical Morquio's disease, released 410 +/- 90 pmol sulfate/h/mg cell protein. The enzyme exhibited a pH optimum of pH 4.8 and a KM of about 1 X 10(-4) mol/1. It was strongly inhibited by phosphate, sulfate and chloride ions. In three cell lines from patients with classical Morquio's disease a residual activity between 1 and 2% of the mean normal activity was found. All cell lines tested released sulfate from 6-sulfo-N-acetylglucosamine-glucuronic acid-[1-3H]-anhydromannitol. Cell extracts from cultured amniotic fluid cells exhibited a N-acetylgalactosamine-6-sulfate sulfatase activity between 120 and 320 pmol/h/mg protein. An enzyme activity of 370 +/- 100 pmol sulfate/h/mg protein was found in peripheral leucocytes from healthy donors. The determination of N-acetyl-galactosamine-6-sulfate sulfatase activity in one family with an affected patient indicated that the enzyme deficiency is also expressed in leucocytes.

MeSH terms

  • Amniotic Fluid / cytology
  • Amniotic Fluid / enzymology
  • Cell Line
  • Child, Preschool
  • Chondroitin Sulfates
  • Chondroitinases and Chondroitin Lyases / deficiency*
  • Chondroitinsulfatases / deficiency*
  • Chondroitinsulfatases / metabolism
  • Chromatography, Ion Exchange
  • Clinical Enzyme Tests* / methods
  • Fibroblasts / enzymology
  • Genotype
  • Humans
  • Leukocytes / enzymology
  • Male
  • Mucopolysaccharidosis IV / diagnosis*
  • Mucopolysaccharidosis IV / enzymology


  • Chondroitin Sulfates
  • Chondroitinsulfatases
  • Chondroitinases and Chondroitin Lyases