Comprehensive spectrum of the ß-Thalassemia mutations in Khuzestan, southwest Iran.

ß-Thalassemia (ß-thal) is characterized by reduction or absence of ß-globin gene expression. We describe the spectrum of mutations observed in a large cohort of ß-thal carriers in Khuzestan, Southwest Iran. All together 1,241 blood samples from individuals with decreased mean corpuscular volume (MCV) and elevated Hb A(2) levels, were analyzed either by reverse dot-blot or by direct sequencing of the HBB gene. We found 42 different mutations associated with ß-thal and identified eight common ß-globin variants, namely, Hb S [ß6(A3)Glu→Val], Hb C [ß6(A3)Glu→Lys], Hb D-Punjab [ß121(GH4)Glu→Gln] and Hb O-Arab [ß121(GH4)Glu→Lys]. No mutations were found in two individuals. The distribution is characteristic of a heterogenous population with three preferential mutations being present [codons 36/37 (-T), IVS-II-1 (G>A) and IVS-I-110 (G>A)] at a frequency of 20.5, 20.0 and 14.2%, respectively, followed by 39 mutations in decreasing frequencies from 5.2 down to 0.1%. These data are of importance when planning prevention strategies in the country.