Extensive gene deletions in Japanese patients with Diamond-Blackfan anemia

Blood. 2012 Mar 8;119(10):2376-84. doi: 10.1182/blood-2011-07-368662. Epub 2012 Jan 18.

Abstract

Fifty percent of Diamond-Blackfan anemia (DBA) patients possess mutations in genes coding for ribosomal proteins (RPs). To identify new mutations, we investigated large deletions in the RP genes RPL5, RPL11, RPL35A, RPS7, RPS10, RPS17, RPS19, RPS24, and RPS26. We developed an easy method based on quantitative-PCR in which the threshold cycle correlates to gene copy number. Using this approach, we were able to diagnose 7 of 27 Japanese patients (25.9%) possessing mutations that were not detected by sequencing. Among these large deletions, similar results were obtained with 6 of 7 patients screened with a single nucleotide polymorphism array. We found an extensive intragenic deletion in RPS19, including exons 1-3. We also found 1 proband with an RPL5 deletion, 1 patient with an RPL35A deletion, 3 with RPS17 deletions, and 1 with an RPS19 deletion. In particular, the large deletions in the RPL5 and RPS17 alleles are novel. All patients with a large deletion had a growth retardation phenotype. Our data suggest that large deletions in RP genes comprise a sizable fraction of DBA patients in Japan. In addition, our novel approach may become a useful tool for screening gene copy numbers of known DBA genes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anemia, Diamond-Blackfan / ethnology
  • Anemia, Diamond-Blackfan / genetics*
  • Anemia, Diamond-Blackfan / pathology
  • Asian People / genetics
  • Child, Preschool
  • DNA Mutational Analysis / methods
  • Female
  • Gene Deletion*
  • Genetic Association Studies
  • Humans
  • Infant
  • Infant, Newborn
  • Japan
  • Male
  • Microarray Analysis / methods
  • Polymerase Chain Reaction
  • Polymorphism, Single Nucleotide
  • Reproducibility of Results
  • Ribosomal Proteins / genetics*

Substances

  • RPL35A protein, human
  • Ribosomal Proteins
  • ribosomal protein L5, human
  • ribosomal protein S17
  • ribosomal protein S19