title: [Genotype of thalassemia genes and the polymorphism of β- globin gene in Cantonese].
abstract: OBJECTIVE
  To understand the genotype of α and β-globin, as well as the polymorphism of β-globin gene in Cantonese in recent years, and to provide an effective genetic diagnosis for thalassemia (thal).
  
  
  METHODS
  The single-tube complex PCR was used to detect 3 types of deletional α-thal, reverse dot blotting (RDB)/PCR to detect 3 kinds of undeletional α-thal-αCS, αQS, αWSand 18 kinds of β-thal mutations which were common in Chinese population. A total of 454 cases from Guangdong were undergone thal genotype genetic diagnosis. Among the 454 cases, 142 cases were selected to perform the single nucleotide polymorphisms (SNPs) analysis of β- globin gene by denaturing high-performance liquid chromatography (DHPLC)combining the whole gene sequencing.
  
  
  RESULTS
  Of the 454 cases, 438 were diagnosed as thalassemia, including 246 of α-thal, 164 of β-thal and 28 of αβ-thal. In 246 α-thal cases, deletions were the dominant mutations, including 197 cases of αα/--(SEA), 20 of αα/-α(3.7) and 9 of αα/-α(4.2). In 164 β- thal cases, heterozygotes accounted for 92.7% (152/164), the main genotypes were CD41- 42, IVS-II-654, ﹣28 and CD17, and the dual heterozygotes and homozygotes accounted for 4.9% (8/164) and 2.4% (4/164), respectively. The result of β-globin gene screening by DHPLC combining with sequencing was consistent with that of RDB. Moreover, we also found 9 kinds of SNP, in which 2 were unreported, the IVS-I-13 G> A and IVS-II- 310 T>C. In the tested samples, the frequency of 4 kinds SNP was high, among which 3 kinds SNPs-rs713040, rs10768683 and rs1609812 were carried together.
  
  
  CONCLUSIONS
  The dominant genotypes were αα/--(SEA) in α-thal cases, CD41-42, IVS-II-654, -28 and CD17 in β-thal. The frequency of β-thal heterozygotes, homozygotes and αβ-thal is high. DHPLC combining the whole β-globin gene sequencing can effectively detect the common β-thal mutation and even new mutations or SNPs. In Cantonese, the frequency of SNP rs713040, rs10768683, rs7480526 and rs1609812 of β-globin gene was high, and there may exist genetic linkage between rs713040, rs10768683 and rs1609812.
authors.affiliation: Department of Medical Genetics, Sun Yet-Sen University Zhongshan School of Medicine, Guangzhou 510080, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Liu
authors.forename: Wei-ying
authors.initials: WY
authors.lastname: Jiang
authors.forename: Shi-yan
authors.initials: SY
authors.lastname: Xu
authors.forename: Juan
authors.initials: J
authors.lastname: Chen
authors.forename: Lu-ming
authors.initials: LM
authors.lastname: Chen
authors.forename: Qiu-hong
authors.initials: QH
authors.lastname: Tian
authors.forename: Ji-cheng
authors.initials: JC
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D004252:DNA Mutational Analysis; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D055815:Young Adult; D017085:alpha-Thalassemia / Q000453:epidemiology / Q000235:genetics*; D055544:beta-Globins / Q000235:genetics*; D017086:beta-Thalassemia / Q000453:epidemiology / Q000235:genetics*
chemical_list: D055544:beta-Globins