Molecular analysis in patients with mucopolysaccharidosis type II suggests that DXS466 maps within the Hunter gene

Hunter disease is an X-linked mucopolysaccharidosis caused by deficiency of the lysosomal enzyme iduronate-2-sulfatase (IDS). Using the IDS cDNA and DNA probes corresponding to loci flanking the IDS locus, we performed molecular genetic studies in two patients with Hunter syndrome. An interstitial deletion spanning the middle part of the IDS gene was found in the first patient. The second patient carries a gross gene rearrangement that can be detected after HindIII or EcoRI digestion of genomic DNA, and is similar to that found recently in seven unrelated Hunter patients. Our data suggest that the structural aberration observed is a partial intragenic inversion. As the same altered hybridization pattern is also revealed by the recently described anonymous DNA probe II-10, which recognizes a frequent TaqI restriction fragment length polymorphism at the DXS466 locus, we conclude that DXS466 maps within the IDS gene, probably in an intron.