Investigation of RFLP Haplotypes β- Globin Gene Cluster in Beta-Thalassemia Patients in Central Iran

Zahra Sajadpour; Zeinab Amini-Farsani; Majid Motovali-Bashi; Mitra Yadollahi; Farrokh Yadollah

doi:10.18502/ijhoscr.v13i2.690

Zahra Sajadpour
Zeinab Amini-Farsani
Majid Motovali-Bashi
Mitra Yadollahi
Farrokh Yadollah

DOI: https://doi.org/10.18502/ijhoscr.v13i2.690

Keywords: Haplotype; Beta-thalassemia; c.315 1G>A; c.92 5G>C; c.93-21G>A

Abstract

Introduction: Beta-thalassemia is one of the most prevalent inherited blood diseases among Iranians. The aim of this study was to elucidate the chromosomal background of beta-thalassemia mutations in Esfahan province, Iran.

Materials and Methods: In this study, we investigated three frequent mutations (c.315+1G>A, c.93-21G>A and c.92+5G>C in β-globin gene, the frequency of RFLP haplotypes, and LD between markers at β-globin gene cluster) in 150 beta-thalassemia patients and 50 healthy individuals. The molecular and population genetic investigations were performed on RFLP markers HindIII in the c.315+1G>A of Gγ (HindIIIG) and Aγ (HindIIIA) genes, AvaII in the c.315+1G>A of β-globin gene and BamHI 3' to the β-globin gene. All statistical analyses were performed using Power Marker software and SISA server.

Results: Fifty percent of beta-thalasemia patients were associated with these mutations. Haplotype I was the most prevalent haplotype among beta-thalassemia patients (39.33%) and normal individuals (46%). The commonest c.315+1G>A mutation in our population was tightly linked with haplotype III (43.75%) and haplotype I (31.25%). The second prevalent mutation, c.92+5G>C, was 90%, 6.66%, and 3.33% in linkage disequilibrium with haplotypes I, VII, and III, respectively. The c.93-21G>A mutation indicated a strong association with haplotype I (80%).

Conclusion: Our study participants like beta-thalassemia patients from Kermanshah province was found to possess a similar haplotype background for common mutations. The emergence of most prevalent mutations on chromosomes with different haplotypes can be explained by gene conversion and recombination. High linkage of a mutation with specific haplotype is consistent with the hypothesis that chromosomes carrying beta-thalassemia mutations experienced positive selection pressure, probably because of the protection against malaria experienced by beta-thalassemia carriers.