ARSB and lysosomal storage disease: Mucopolysaccharidosis type VI (MPS VI) or Maroteaux-Lamy syndrome is an autosomal recessive lysosomal storage disorder described by Pierre Maroteaux and Maurice Lamy in 1963[1] and due to mutations in the arylsulfatase B gene (ARSB) located in chromosome 5 (5q13–5q14).[2] Pathogenic mutations of this gene result in either reduced or absence of the enzyme arylsulfatase B (ASB) activity, also called N-acetylgalactosamine 4-sulfatase (E.C.3.1.6.12), leading to incomplete degradation and cellular accumulation of the glycosaminoglycan (s) (GAGs).