BONE-MARROW TRANSPLANTATION IN HUNTER SYNDROME

Hunter syndrome (mucopolysaccharidosis II) is a rare X-linked disorder of mucopolysaccharide metabolism that typically progresses to severe mental retardation and death by 18 years of age. A child with Hunter s yndrome received an allogeneic bone marrow transplantation from an una ffected human leukocyte antigen-identical sibling at the age of 29 mon ths without complications. Despite full and sustained engraftment now at 70 months after transplantation, the patient's neurocognitive abili ties have continued to deteriorate. In this case, replacement of defec tive marrow-derived macrophages by bone marrow transplantation was not effective in preventing the neurologic progression of the disease in a child with the severe phenotype of Hunter syndrome.