IDS gene-pseudogene exchange responsible for an intragenic deletion in a Hunter patient

Hum Mutat. 1996;8(1):44-50. doi: 10.1002/(SICI)1098-1004(1996)8:1<44::AID-HUMU6>3.0.CO;2-P.


Hunter disease or mucopolysaccharidosis type II is an X-linked disease caused by the deficiency of the lysosomal enzyme iduronate-2-sulfatase (IDS). The IDS gene (24 kb) contains nine exons and has been completely sequenced. A pseudogene (IDS-2 locus) distal to the functional IDS gene has recently been identified. This work reports the characterization of IDS gene alterations in two severely affected patients. Patient 1 has a partial deletion that removes exons I to VI and extends about 200 kb upstream of the IDS gene. Patient 2 has an internal deletion of exons IV, V, VI, and VII, which results from an IDS gene-pseudogene exchange between highly homologous regions. In the rearranged gene, the junction intron contains pseudogene intron 3- and intron 7-related sequences. An interchromosomal recombination is probably the cause of this rearranged X chromosome.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Gene Rearrangement
  • Humans
  • Iduronate Sulfatase / genetics*
  • Mucopolysaccharidosis II / genetics*
  • Mutation*
  • Polymerase Chain Reaction
  • Pseudogenes*
  • RNA, Messenger / genetics


  • RNA, Messenger
  • Iduronate Sulfatase