Mucopolysaccharidosis type VI (MPS VI), or Maroteaux-Lamy syndrome, is a lysosomal storage disorder that results from a deficiency of the enzyme N-acetylgalactosamine-4-sulfatase or arylsulfatase B (ASB). It is a relatively rare disorder, with an estimated incidence of 1 in 248,000 to 1 in 300,000.