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The major defect in α-thalassemia (α-thal) is a single or double gene deletion. The aim of this study was to evaluate the α-thal mutations in two provinces of Southern Iran, Fars & Kohkeloye and Bouyer Ahmad. A total of 2000 subjects with microcytic hypochromic anemia was selected as a study group; finally, 1177 subjects were found to be α-thal mutation carriers by gap-polymerase chain reaction (gap-PCR) protocols and were confirmed by multiplex PCR and reverse hybridization test strips. A total of 1195 mutated α-globin alleles was identified in these patients that includes at least 10 different gene mutations. The most common mutation found was -α3.7 (rightward deletion) (71.7%%) and α−5 nt (IVS-I, -TGAGG) and the polyadenylation signal site (poly A1; AATAA A>AATAA G) were the second and third most common mutations (7.0 and 4.2%%, respectively). In countries like Iran, with a high prevalence of thalassemia, identifying different mutations is helpful in carrier screening, genetic counseling and prenatal diagnosis of at-risk couples for the prevention of the birth of babies affected by severe thalassemic anomalies. [ABSTRACT FROM AUTHOR]

Hb Constant Spring (Hb CS, codon 142, TAA>CAA, α2) (HBA2:c.427T>C) and α2 IVS-I donor site (GAGGTGAGG>GAGG - - - - -) (HBA2:c.95++2_95++6delTGAGG) are nondeletional α-thalassemia (α-thal) mutations found all over the world. Identification of α-thal genotypes in at-risk couples for severe anemia or in highly heterogeneous populations requires rapid, accurate and cost-effective genotyping methods. In this study, a pair of primers were used to specifically amplify an 883 bp fragment from the α2-globin gene in order to simultaneously identify these two mutations by a PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) method. We determined the genotypic frequencies of Hb CS and the α2 IVS-I donor site mutations after amplification and enzymatic digestion with Tru9I in 238 northern Iranian samples referred for α-thal testing. Hb CS and the α2 IVS-I donor site mutations accounted for 21 (8.8%%) and 29 (12.2%%) of the nondeletional cases. This genotyping assay has proven to be a rapid, reliable and useful diagnostic tool for simultaneous detection of these two anomalies for genetic counseling or further prenatal diagnosis. [ABSTRACT FROM AUTHOR]