Published in:
Open Access 01-12-2019 | Thalassemia | Research article
Molecular characterization of β-thalassemia intermedia in the West Bank, Palestine
Published in: BMC Hematology | Issue 1/2019
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Background
We aimed to investigate the molecular basis of β-Thalassemia intermedia (TI) in the West Bank region and its management practices.
Methods
This was a case series multi-center study and included 51 cases of TI. DNA sequencing was used to analyze β-globin gene mutations. Common α-globin gene mutations were screened by Gap-PCR (−α3.7, −α4.2, −-MED, αααanti3.7) or DNA sequencing (α2-IVS II 5 nt del). XmnI -158 C > T polymorphisms of Gγ-globin gene was determined by RFLP-PCR.
Results
Seven β-globin gene mutations were observed, namely IVS-I -6 C > T, IVS-I-110 G > A, IVS-II-1 G > A, IVS-I-1 G > A, Codon 37 Trp > Stop, beta − 101 and IVS-II-848 C > A. Ten genotypes were observed. Homozygosity for IVS-I-6 accounted for the majority of TI cases with a frequency of 74.5%. The second common β-globin gene genotype was homozygote IVS-I-110 G > A (5.8%) and homozygote IVS-II-1 G > A (5.8%). The remaining seven genotypes were each detected in about 2% of patients. α-Thalassemia mutations were seen in five patients (9.8%), and included (−α3.7, αααanti3.7 and α2-IVSII-5 nt del). XmnI polymorphism was observed in four patients (7.8%), three homozygotes and one heterozygote.
Conclusions
Homozygosity for the mild β-globin gene IVS-I-6 allele was the major contributing factor for the TI phenotype among the study subjects. The role of XmnI SNP and α-thalassemia mutations in ameliorating the TI phenotype was observed in few patients for each factor. The beta − 101 C > T mutation was diagnosed in one patient in homozygote state for the first time in Palestine.