Evaluation of α-Globin Gene Mutations Among Different Ethnic Groups in Khuzestan Province, Southwest Iran

Abstract

α-Thalassemia (α-thal) is one of the most common inherited hemoglobin (Hb) disorders in the world. In addition to large deletions, over 50 different α-thal point mutations were detected around the world, thus, patients showed different phenotypes with regard to genotype. This study evaluated the genetic frequency of α-thal in Khuzestan Province, Southwest Iran, to help implement premarital and prenatal screening programs. The study was conducted on couples proposing to get married and parents who were referred to the genetic center of Shafa Hospital, Ahvaz, Iran, for prenatal diagnosis (PND) in 2012. Genomic DNA was purified by the salting-out method and tested using multiplex gap-polymerase chain reaction (gap-PCR), amplification refractory mutation system-PCR (ARMS-PCR), reverse hybridization test strips and DNA sequencing. Overall, 11 mutations were found on the α-globin genes. Based on gene frequency, the most common mutant allele was –α^3.7 (rightward) (71.3%) followed by the two gene deletion – –^MED (9.7%). Other common mutations were α^{codon 19}α (GCG>GC–, α2) (8.4%), the polyadenylation (polyA1) site α^polyA1α (AATAAA>AATAAG) (2.8%), and α^{–5 nt}α (–TGAGG) (2.0%). In addition, an extremely rare mutation at α^{codon 21}α [Hb Fontainebleau, HBA2: c.64G > C (or HBA1)] was also found. The results of this study are critical for correct diagnosis of α-thal carriers, premarriage counseling and PND. This study suggests that the distribution of mutations on the α-globin genes differs among the ethnic groups in Khuzestan Province as well as in other provinces.

• α-Globin gene mutation
• α-thalassemia (α-thal)
• Iran
• Khuzestan

Acknowledgments

This study was carried out at Ahwaz Shafa Hospital, Ahwaz, Iran. We are grateful to the personnel of the hospital. We are also grateful to Dr. Pedram, Dr. Keikhaei and Ms. Asadi (Tehran University of Medical Sciences, Tehran, Iran) for revising the manuscript.

Declaration of interest

This study was financially supported by grant 90S6 from Vice-Chancellor for Research Affairs of Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.