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Novel deletions of 14q11.2 associated with developmental delay, cognitive impairment and similar minor anomalies in three children
  1. Farah Zahir1,
  2. Helen V Firth2,
  3. Agnes Baross3,
  4. Allen D Delaney3,
  5. Patrice Eydoux4,
  6. William T Gibson1,
  7. Sylvie Langlois1,
  8. Howard Martin2,
  9. Lionel Willatt2,
  10. Marco A Marra1,3,
  11. Jan M Friedman1
  1. 1Department of Medical Genetics, University of British Columbia, Vancouver, Canada
  2. 2Department of Medical Genetics, Addenbrookes Hospital, Cambridge, United Kingdom
  3. 3BC Cancer Agency Genome Sciences Center, Vancouver, Canada
  4. 4Department of Pathology and Laboratory Medicine, Children’s and Women’s Health Centre of BC, Vancouver, Canada
  1. Correspondence to:
 Farah Zahir
 Medical Genetics Research Unit, University of British Columbia, Box 153, Children’s and Women’s Hospital, 4500 Oak Street, Vancouver, BC, Canada V6H 3N1; farahz{at}interchange.ubc.ca

Abstract

Methods and results: We identified de novo submicroscopic chromosome 14q11.2 deletions in two children with idiopathic developmental delay and cognitive impairment. Vancouver patient 5566 has a ∼200 kb deletion and Vancouver patient 8326 has a ∼1.6 Mb deletion. The Database of Chromosomal Imbalance and Phenotype in Humans using Ensembl Resources (DECIPHER) revealed a third patient with idiopathic developmental delay and cognitive impairment, DECIPHER patient 126, who has a ∼1.1 Mb deletion of 14q11.2. The deletion of patient 5566 overlaps that of patient 126 and both of these deletions lie entirely within that of patient 8326. All three children have similar dysmorphic features, including widely-spaced eyes, short nose with flat nasal bridge, long philtrum, prominent Cupid’s bow of the upper lip, full lower lip and similar auricular anomalies.

Conclusion: The minimal common deletion region on chromosome 14q11.2 is only ∼35 kb (from 20.897 to 20.932, University of California at Santa Cruz (UCSC) Genome Browser; build hg18, March 2006) and includes only two genes, SUPT16H and CHD8, which are good candidate genes for the phenotypes. The non-recurrent breakpoints of these patients, the presence of normal copy number variants in the region and the local genomic structure support the notion that this region has reduced stability.

  • AGH, array genome hybridisation
  • CNV, copy number variants
  • DECIPHER, DatabasE of Chromosomal Imbalance and Phenotype in Humans using Ensembl Resources
  • DEI, duplication enrichment index
  • FACT, FACT, facilitates chromatin transcription
  • FISH, fluorescence in situ hybridisation
  • LCR, low copy repeat
  • MR, mental retardation
  • SNP, single nucleotide polymorphism
  • UCSC, University of California at Santa Cruz
  • mental retardation
  • microdeletion
  • 14q11.2
  • SUPT16H. CHD8

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Footnotes

  • Published Online First 1 June 2007

  • This work was supported by funding from Genome Canada and Genome British Columbia. WT Gibson is supported by a CIHR Institute of Genetics Clinical Investigatorship Award. MA Marra is a scholar of the Michael Smith Foundation for Health Research.

  • Competing interests: None declared.

  • Parental/guardian informed consents were obtained for publication of figure 1.

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