Unrelated umbilical cord blood transplantation in infancy for mucopolysaccharidosis type IIB (Hunter syndrome) complicated by autoimmune hemolytic anemia

This report describes unrelated umbilical cord blood transplantation for a 10-month-old infant boy with mucopolysaccharidosis IIB (Hunter syndrome), an X-linked metabolic storage disorder due to deficiency of iduronate sulfatase, Two years after transplant similar to 55% normal plasma enzyme activity has been restored and abnormal urinary excretion of glycosaminoglycans has nearly completely resolved. The boy has exhibited normal growth and development after transplant. Nine months after transplant he developed severe autoimmune hemolytic anemia and required 14 months of corticosteroid treatment to prevent clinically significant anemia. Bone marrow transplantation for Hunter syndrome and post-transplant hemolytic anemia are reviewed.