title: Detection of PAX2 deletions and duplications using multiplex ligation-dependent probe amplification.
abstract: BACKGROUND
  Renal coloboma syndrome (RCS) is a rare inherited disorder caused by mutations in the PAX2 gene. Clinical testing is currently performed by bidirectional Sanger sequencing of all 12 coding exons of the PAX2 gene, which detects point mutations or small insertion/deletion mutations. Large genomic deletions of PAX2 have been identified in 3/90 known RCS families, accounting for approximately (3%) of RCS cases. In these cases, the deletion was detected by cytogenetic techniques such as G-banding or array comparative genomic hybridization. While these methods would be sufficient to identify whole gene deletions, they may not be able to identify smaller rearrangements affecting single exons. Similarly, such deletions would not be detected by Sanger sequencing.
  
  
  OBJECTIVE
  The aim of this study was to determine whether mutation-negative RCS probands harbor a genomic deletion or duplication involving one or more exons of the PAX2 gene. We evaluated this hypothesis in 46 patients with a clinical suspicion of RCS in whom no mutations were identified.
  
  
  RESULTS
  We developed a multiplex ligation-dependent probe amplification assay to detect gene deletion/duplication in all 12 exons of the PAX2 gene. Of the 46 PAX2 mutation-negative samples tested, none demonstrated deletions or duplications in the PAX2 gene. This suggests that deletions or duplications in PAX2 are unlikely to significantly contribute to the pathogenesis of RCS, beyond the known 3% of cases that have been attributed to whole gene deletions. Given these results, we hypothesize that other genes and/or locus control regions regulating PAX2 may be involved in the pathogenesis of PAX2 mutation-negative cases of RCS.
authors.affiliation: 1 Department of Laboratory Medicine and Pathology, University of Minnesota , Minneapolis, Minnesota.
authors.forename: Amy B
authors.initials: AB
authors.lastname: Karger
authors.forename: Jon D
authors.initials: JD
authors.lastname: Wilson
authors.forename: Matthew
authors.initials: M
authors.lastname: Bower
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Schimmenti
authors.forename: Bharat
authors.initials: B
authors.lastname: Thyagarajan
mesh_terms: D003103:Coloboma / Q000235:genetics*; D005091:Exons / Q000235:genetics; D005260:Female; D017353:Gene Deletion; D020440:Gene Duplication; D006801:Humans; D008297:Male; D060885:Multiplex Polymerase Chain Reaction / Q000379:methods*; D051762:PAX2 Transcription Factor / Q000235:genetics*; D051437:Renal Insufficiency / Q000235:genetics*; D014718:Vesico-Ureteral Reflux / Q000235:genetics*
chemical_list: D051762:PAX2 Transcription Factor; C497318:PAX2 protein, human