Fine mapping of breakpoints in two unrelated patients with rare overlapping interstitial deletions of 9q with mild dysmorphic features

Anita S. Kulharya, David B. Flannery, Karen Norris, Carolyn Lovell, Brynn Levy, Gopalrao V.N. Velagaleti

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

Approximately, 20 cases of interstitial deletions of 9q have been reported in the literature spanning the breakpoints from 9q21 to 9q34. Unlike the 9q subtelomeric deletions, the interstitial deletions do not demonstrate a specific recognizable phenotype, although the majority of patients had microcephaly. Lack of precise molecular delineation of the extent of deletions in the published cases makes it difficult to develop an accurate genotype-phenotype correlation. We report on fine mapping of breakpoints using the Affymetrix Human Mapping 500K Array Set in two unrelated female patients with overlapping de novo deletion in 9q. SNP oligonucleotide microarray analysis (SOMA) indicated these to be relatively large deletions with Patient 1 having a 6.47 Mb deletion (>60 genes) spanning 9q32-q33-2 and Patient 2 having a 9.68 Mb deletion (>20 genes) localized to 9q311-q33.1. FISH analysis with BAC clones localized to the breakpoints showed discrepant results in Patient 1. Based on the review of previously reported interstitial 9q deletion patients and our patients, the minimal region of overlap (MRO) appears to encompass the 9q32 region and a phenotype characterized by microcephaly, neurological dysfunction and facial dysmorphism can be deduced. Our study shows the investigative nature of the latest array technology and the limitations of this technology in the accurate delineation of breakpoints.

Original languageEnglish (US)
Pages (from-to)2234-2241
Number of pages8
JournalAmerican Journal of Medical Genetics, Part A
Volume146
Issue number17
DOIs
StatePublished - Sep 1 2008
Externally publishedYes

Keywords

  • 9q deletion
  • Array-CGH
  • Developmental delay
  • Dysmorphic
  • FISH
  • Microcephaly

ASJC Scopus subject areas

  • Genetics
  • Genetics(clinical)

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