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J Med Genet 41:941-945 doi:10.1136/jmg.2004.021501
  • Short report

Localisation of a gene for mucopolysaccharidosis IIIC to the pericentromeric region of chromosome 8

  1. J Ausseil1,
  2. J C Loredo-Osti2,
  3. A Verner3,
  4. C Darmond-Zwaig3,
  5. I Maire4,
  6. B Poorthuis5,
  7. O P van Diggelen6,
  8. T J Hudson2,3,7,
  9. T M Fujiwara2,7,
  10. K Morgan2,7,
  11. A V Pshezhetsky1
  1. 1Hôpital Sainte-Justine and Département de Pédiatrie, Université de Montréal, Montréal, Québec, Canada
  2. 2Department of Human Genetics, McGill University, Montréal, Québec, Canada
  3. 3McGill University and Genome Quebec Innovation Centre, Montréal, Québec, Canada
  4. 4Hôpital Debrousse, Lyon Cedex 05, Lyon, France
  5. 5Department of Pediatrics and Clinical Genetics, Leiden University Medical Center, Leiden, the Netherlands
  6. 6Department of Clinical Genetics, Erasmus University, Rotterdam, the Netherlands
  7. 7Department of Medicine, McGill University, Montréal, Québec, Canada
  1. Correspondence to:
 Dr A V Pshezhetsky
 Service de Génétique Médicale, Hôpital Sainte-Justine, 3175 Côte Ste-Catherine, Montréal, Québec H3T 1C5, Canada; alexei.pchejetskiumontreal.ca
  • Received 6 April 2004
  • Accepted 18 June 2004

Abstract

Mucopolysaccharidosis type IIIC (MPS IIIC, or Sanfilippo syndrome C) is a rare lysosomal storage disorder caused by a deficiency of acetyl-coenzyme A:α-glucosaminide-N-acetyltransferase. Patients develop progressive neuropsychiatric problems, mental retardation, hearing loss, and relatively minor visceral manifestations. The pattern of transmission is consistent with an autosomal recessive mode of inheritance. The aim of this study was to find a locus for MPS IIIC using a homozygosity mapping approach. A genomewide scan was performed on DNA from 27 affected individuals and 17 of their unaffected relatives. Additional patients were recruited, and DNA was obtained from a total of 44 affected individuals and 18 unaffected family members from 31 families from 10 countries. A working candidate interval was defined by looking for excess homozygosity in patients compared with their relatives. Additional markers were genotyped in regions of interest. Linkage analysis was performed to support the informal analysis. Inspection of the genomewide scan data showed apparent excess homozygosity in patients compared with their relatives for markers on chromosome 8. Additional genotyping identified 15 consecutive markers (from D8S1051 to D8S2332) in an 8.3 cM interval for which the genotypes of affected siblings were identical in state. A maximum multipoint lod score of 10.61 was found at marker D8S519. A locus for MPS IIIC maps to an 8.3 cM (16 Mbp) interval in the pericentromeric region of chromosome 8.

Footnotes

  • The first two authors contributed equally to this work, and the last two authors share senior authorship.

  • Conflict of interest: none declared