Hunter Syndrome (MPS II) Enzyme Replacement Therapy (ERT) Study

Hunter Syndrome or Mucopolysaccharidosis II (MPS II) is a rare genetic disorder caused by decreased levels of a specific enzyme, iduronate-2-sulfatase. Lack of this enzyme causes buildup of large sugar molecules called glycosaminoglycans (GAGs). The build up of GAGs causes significant damage to the body and brain. This study is evaluating the use of JR-141, an enzyme replacement therapy, to provide the missing enzyme to the body. This allows for break down of the stored GAGs. JR-141 uses specific technology to cross the blood brain barrier so that the enzyme can get into the brain. JR-141 is expected to help both the cognitive (brain) and body effects of MPS II.