title: The importance of β globin deletion analysis in the evaluation of patients with β thalassemia.
abstract: BACKGROUND
  Beta globin deletion/duplication analysis may serve as a useful adjunct to sequence analysis. Our purpose was to develop a robust assay for beta globin deletion/duplication analysis and determine its role in evaluating patients with beta thalassemia.
  
  
  METHODS
  A single tube semi-quantitative fluorescent PCR assay capable of detecting deletions and duplications in the beta globin cluster and the associated locus control region (LCR) was developed and validated.
  
  
  RESULTS
  Six hundred seventy one de-identified samples submitted for beta globin sequence analysis were tested for deletions and duplications of the beta globin cluster. Twenty-two deletions were detected (3%, 22/671). Seventeen of the 22 (82%) deletion samples were negative for mutations in the whole gene sequencing assay. For 5 of the samples, homozygous point mutations were inferred by beta globin sequencing. Among the deletions detected, 11 (50%) involved only the beta globin gene (5 covering the entire gene, 2 spanning the 5' end of the gene and 4 encompassing the 3' end of the gene). Ten samples (45%) were heterozygous delta-beta deletions spanning both the delta globin and beta globin genes. One patient with a single deletion had Hb Lepore.
  
  
  CONCLUSIONS
  Beta globin deletion/duplication analysis is necessary to correctly identify the genotype in some patients being evaluated for beta thalassemia.
authors.affiliation: Department of Molecular Genetics, Quest Diagnostics Nichols Institute, San Juan Capistrano, CA 96690, USA. mario.x.mikula@questdiagnostics.com
authors.forename: M
authors.initials: M
authors.lastname: Mikula
authors.forename: A
authors.initials: A
authors.lastname: Buller-Burckle
authors.forename: M
authors.initials: M
authors.lastname: Gallivan
authors.forename: W
authors.initials: W
authors.lastname: Sun
authors.forename: C R
authors.initials: CR
authors.lastname: Franklin
authors.forename: C M
authors.initials: CM
authors.lastname: Strom
mesh_terms: D017353:Gene Deletion; D023061:Gene Order; D005838:Genotype; D006455:Hemoglobins, Abnormal / Q000235:genetics; D006801:Humans; D055544:beta-Globins / Q000235:genetics*; D017086:beta-Thalassemia / Q000175:diagnosis* / Q000235:genetics*
chemical_list: D006455:Hemoglobins, Abnormal; D055544:beta-Globins