Infants in Taiwan are not permitted to receive ERT for Hunter syndrome unless their clinical and laboratory findings meet the guidelines for treatment issued by the National Health Insurance Bureau of Taiwan, which include the onset of one or more MPS signs or symptoms, deficiency of leukocyte IDS activity, identification of IDS variants, elevated urinary GAG levels, and definite evidence of a family history. This evidence concerns the gene IDS and mucopolysaccharidosis.