Molecular Analysis in Two Siblings African Patients with Severe Form of Hunter Syndrome: Identification of a Novel (p.Y54X) Nonsense Mutation

Hunter syndrome (or Mucopolysaccharidosis type II, MPS II) is an X-linked recessive disorder due to the deficiency of the iduronate-2-sulfatase (IDS) enzyme, resulting in the accumulation of heparan and dermatan sulfates in the lysosomes. The heterogeneity of clinical phenotypes, ranging from mild-to-severe forms, is a result of different mutations in the IDS gene. We report here, a novel nonsense mutation (p.Y54X) in two siblings MPS II African patients affected with a severe form of the disease. We postulated that the p.Y54X mutation which causes a loss of the IDS region highly conserved among sulfatase enzymes, could be predicted as a severe disease-causing mutation for Hunter syndrome.