Litjens et al, (1992) [64] reported a patient homozygous for an early frameshift mutation caused by the deletion of a G at position 238 (ΔG238) with a description of a rapidly progressing MPS VI phenotype as having a grossly elevated level of DS, deficiency of ASB in skin fibroblasts and peripheral blood leukocytes. The gene discussed is ARSB; the disease is mucopolysaccharidosis type 6.