Molecular Analysis of α/β -Thalassemia in A Southern Chinese Population

Abstract

Thalassemia is endemic to many regions in southern China. The screening of severe determinants of thalassemia is of critical importance in management and control of thalassemia. We designed a protocol based on microarray technology to screen for a spectrum of α/β-globin gene mutations in the Chinese population. A total of 38 probes were capable of screening 98% of α/β-globin gene mutations in the China population, including 16 mutations of β-globin [β(41–42)(−TCTT), IVSII-654(C→T), β17(A→T), −28(A→G), β(71–72)(+A), β(71–72)(+T), HbE26(G→A), −29(A→G), β(27–28)(+C), IVSI-1(G→T), IVSI-5(G→C), β(14-15)(+G), IVSII-5(G→C), β41(+T), 37(G→A), and β43(G→T)] and five mutations of α/β[three deletions of −α;^3.7, −α^4.2, and −−^SEA; two nondeletions of α^{Quong Sze} codon α125(T→C) and α^{Constant Spring} codon α142(T→C)]. Multiplex PCR products were amplified from human genomic DNA and allowed to hybridize with the oligonucleotide array. α/β-Globin genotypes were assigned by quantitative analysis of the hybridization results. The protocol, standardized by analysis of 100 thalassemia samples with known mutations and 13 recombinant plasmids, was 100% reliable in genotyping all mutant alleles. In subsequent screening of 2,030 Chinese with unknown mutations, the protocol was 100% accurate. This method provides unambiguous detection of complex combinations of heterozygous, compound heterozygous, and homozygous α/β-thalassemia genotypes. The protocol was also flexible, detecting globin gene mutations from different population groups.