title: Evaluation of clinical application of gap-PCR as a routine method for alpha-thalassemia carrier detection.
abstract: OBJECTIVE
  To evaluate the feasibility of using gap-PCR for routine screening of alpha-thalassemia in clinical laboratory.
  
  
  METHODS
  A total of 382 clinical blood samples randomly collected from the population of Zhuhai city were screened for alpha-thalassemia determinants with hematological and gap-PCR method respectively in a double-blind manner. Parallel analysis with Southern blotting was performed to verify the genotyping results by PCR.
  
  
  RESULTS
  Of the 382 samples tested, 3 common alpha-thalassemia genes with genotypes of --(SEA)/alpha alpha, -alpha(3.7)/alpha alpha and -alpha(4.2)/alpha alpha were detected in 21 (5.50%), 7 (1.83%) and 3 (0.79%) cases respectively by gap-PCR, including 7 cases with normal phenotype and 3 case of iron-deficiency anemia. The overall incidence of alpha-thalassemia was 8.12% in the population of Zhuhai city, as determined by gap-PCR, in total agreement with the results by Southern blotting. Only 21 of the 31 alpha-thalassemia cases were identified by hematological analysis (besides 2 cases with alpha-thalassemia phenotype undetermined), which had a false-negative rate of 32.3%. Seven silent alpha-thalassemia and 3 mild alpha-thalassemia cases failed to be detected by hematological analysis, resulting in a rate of 2.62% for failure of detection.
  
  
  CONCLUSIONS
  Gap-PCR method is specific and feasible as a better alternative for alpha-thalassemia screening, especially advantageous in detecting silent carriers in comparison with hematological method.
authors.affiliation: Women and Children's Healthcare Hospital of Zhuhai City, Zhuhai 519001, China.
authors.forename: Yu-Qiu
authors.initials: YQ
authors.lastname: Zhou
authors.forename: Ge-Fei
authors.initials: GF
authors.lastname: Xiao
authors.forename: Li-Yan
authors.initials: LY
authors.lastname: Li
authors.forename: Wen-Dian
authors.initials: WD
authors.lastname: Li
authors.forename: Zhong-Ying
authors.initials: ZY
authors.lastname: Liu
authors.forename: Lan-Fang
authors.initials: LF
authors.lastname: Zhu
authors.forename: Qiu-Hua
authors.initials: QH
authors.lastname: Mo
authors.forename: Xin-Jun
authors.initials: XJ
authors.lastname: Qu
authors.forename: Xiang-Min
authors.initials: XM
authors.lastname: Xu
mesh_terms: D004247:DNA / Q000235:genetics; D005260:Female; D006580:Genetic Carrier Screening / Q000379:methods*; D005838:Genotype; D006579:Heterozygote; D006801:Humans; D008297:Male; D010641:Phenotype; D016133:Polymerase Chain Reaction / Q000379:methods*; D017085:alpha-Thalassemia / Q000175:diagnosis / Q000235:genetics*
chemical_list: D004247:DNA