Maroteaux-Lamy disease (mucopolysaccharidosis VI), subtype A: deficiency of a N-acetylgalactosamine-4-sulfatase

The non-reducing terminal moiety of ³⁵SO₄-dermatan sulfate accumulating in fibroblasts cultured from the skin of patients with one form of Maroteaux-Lamy disease was found to be N-acetylgalactosamine-4-sulfate. This end group accounted for about 3 % of the total radioactivity. Using both ³⁵SO₄- and ¹⁴C-N-acetylgalactosamine-labeled dermatan sulfates from the patients fibroblasts as substrates, it was found that homogenates of Maroteaux-Lamy fibroblasts, but not of normal, Hurler and Sandhoff fibroblasts fail to cleave inorganic sulfate from the non-reducing termini. We conclude, that deficiency of N-acetylgalactosamine-4-sulfatase is the biochemical basis for this form of Maroteaux-Lamy disease.