Bone marrow transplantation in a Hunter patient with P266H mutation

Mucopolysaccharidosis type II (MPS II, Hunter syndrome) is a lysosomal dise ase caused by the deficiency of the enzyme iduronate-2-sulfatase (IDS, EC 3 .1.6.13). Affected patients show a wide spectrum of clinical phenotypes, fr om severe to mild. Mutational analysis on this disease resulted in the iden tification of more than 200 alterations. Bone marrow transplantation (BMT) is considered, at present, an appropriate therapy for MPS II subjects witho ut severe neuropsychological impairment, however molecular analysis in BMT treated patients has been poorly studied. We describe here a patient subjec ted to BMT in 1995 whose IDS gene alteration, mutation P266H, was identifie d thereafter. The 4-year follow-up included clinical, biochemical and molec ular parameters. DNA analysis showed, after BMT, coexisting host mutant and donor normal alleles, ensuring the effectiveness of the therapy and provid ing a fast and accurate tool to monitor the colonization of donor cells aft er treatment.