Diagnostic difficulties in patients with attenuated form of MPS VI

Background Mucopolysaccharidosis VI (MPS VI, Maroteaux-Lamy syndrome) is an autosomal recessive lysosomal storage disorder determined by mutations in the arylsulfatase B gene located in chromosome 5. Pathogenic mutations of this gene result in reduced or absent activity of enzyme arylsulfatase B (N-acetylgalactosamine 4-sulfatase, ARSB). Incomplete degradation and cellular accumulation of glycosaminoglycans (dermatan sulfate) result in cell and tissue injury following clinical manifestation. Three major clinical phenotypes of the disease could be distinguished among our patients: severe, and intermediate. Because patients with an attenuated MPS VI phenotype present with disease symptoms late in life, it is highly probable that they may be remain under diagnosed and/or misdiagnosed.