Identification of α-globin Chain Variants: A Report from Iran

BACKGROUND: This study was carried out to identify molecular and hematological features of α- globin chain variants and to evaluate their effects on the clinical and hematological characteristics in Iranian individuals suspected of having thalassemia trait.METHODS: Analysis of red blood cell indices, hemoglobin (Hb) analysis and genomic DNA isolation were carried out according to standard methods. For identifying the α-thalassemia (α-thal)genotype, investigation of common Mediterraneana-globin gene deletions (-a3.7, -a4.2 -a20.5 and --MED) was performed by Gap-PCR.To characterize chain variants the entire α1 and α2 genes that spanned from the promoter region to the poly A tail were amplified and directly sequenced.RESULTS: In this study, 19 members of 17 unrelated families showed α-chain variants. Among these cases ten α-chain variantsthat included Hb Setif, Hb Constant Spring (Hb CS), Hb Handsworth, Hb Icaria, Hb Evanston, Hb Val de Marne, Hb Utrecht, Hb Savaria, Hb Adana, and Hb Dartmouth were identified. The hematological profile and molecular basis of these ten α-chain variants and the phenotypic consequences of their interactions were discussed. CONCLUSIONS: The knowledge of the spectrum of α-globin variants present in the Iranian population is essential for the molecular diagnosis and prevention of hemoglobinopathies