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Published on: September 6, 2017
Molecular characterization of β-thalassemia intermedia: a report from Iran
Aida Arab1, Morteza Karimipoor, Ali Rajabi
1Molecular Medicine Department, Biotechnology Research Center, Pasteur Institute of Iran, Pasteur Street, 13164 Tehran, Iran.
Abstract:
Thalassemia intermedia is a clinical definition applied to patients whose clinical phenotype is milder than thalassemia major. To characterize different common mechanisms involving in pathogenesis of moderate to severe β-thalassemia intermedia, we have studied four factors in 38 Iranian patients with thalassemia intermedia: β-globin gene mutation, deletion in α-globin genes, presence of XmnI polymprphism and RFLP haplotype at β-globin gene cluster. The results showed that 84.4% of patients were associated with severe mutations in β-globin gene, mainly IVSII-1(G to A) (56.4%). The positive XmnI polymorphism was seen in 76.9% of the studied alleles which showed strong linkage to β° mutations and high level of fetal hemoglobin. Co-existence of α-globin gene deletions, β(+) mutation and the most frequent of RFLP haplotype (-/-, +/+, -/+, +/+, +/+, +/+, -/-) were seen in 7.7, 12.8 and 17.9%, respectively. In this group of our study it seems the main ameliorating factor in the patients was co-inheritance of a positive XmnI polymorphism with β° mutation especially IVSII-1, which were associated with increased production of fetal hemoglobin. However, the other probable genetic factors should be investigated to describe genotype-phenotype correlation in thalassemia intermedia patients.
Insights
Thalassemia intermedia patients often have severe beta-globin gene mutations. A positive XmnI polymorphism, especially with IVSII-1 mutation, appears to be a key factor improving fetal hemoglobin levels.
Area of Science:
- Genetics
- Hematology
- Molecular Biology
Background:
- Thalassemia intermedia presents a milder phenotype than thalassemia major.
- Understanding the genetic mechanisms of moderate to severe beta-thalassemia intermedia is crucial for patient management.
Purpose of the Study:
- To investigate common genetic factors contributing to the pathogenesis of thalassemia intermedia.
- To analyze the correlation between specific genetic mutations, polymorphisms, and clinical phenotypes in Iranian patients.
Main Methods:
- Studied 38 Iranian patients diagnosed with thalassemia intermedia.
- Analyzed four genetic factors: beta-globin gene mutations, alpha-globin gene deletions, XmnI polymorphism, and RFLP haplotype.
Main Results:
- 84.4% of patients had severe beta-globin gene mutations, predominantly IVSII-1 (G to A) (56.4%).
- Positive XmnI polymorphism (76.9%) was linked to beta° mutations and elevated fetal hemoglobin.
- Co-inheritance of alpha-globin deletions, beta(+) mutation, and specific RFLP haplotypes were observed in 7.7%, 12.8%, and 17.9% of cases, respectively.
Conclusions:
- Co-inheritance of positive XmnI polymorphism with beta° mutations (especially IVSII-1) is a significant ameliorating factor in thalassemia intermedia.
- Increased fetal hemoglobin production is associated with the XmnI polymorphism and beta° mutations.
- Further research into other genetic factors is needed to fully elucidate genotype-phenotype correlations in thalassemia intermedia.
