Prevalence and Molecular Characterization of β-Thalassemia in Kirkuk Province of Northern Iraq.

To determine the prevalence and molecular basis of β-thalassemia in the Northeastern Iraqi province of Kirkuk, a total of 3954 individuals attending the provincial premarital screening center were recruited. The prevalence of β-thalassemia minor among the screened individuals was found to be 3.0%, while those of Hemoglobin E, and δβ-thalassemia carrier states were 0.05%, and 0.03% respectively. Molecular characterization of the β-thalassemia mutations was achieved by multiplex PCR and reverse hybridization, followed by next generation sequencing for those left uncharacterized by the former technique. Among 19 β-thalassemia mutations identified, seven were the most frequent, namely: IVS-II-1 (G > A), codon 8/9 (+G), IVS-I-6 (T > C), IVS-I-110 (G > A), IVS-I-I (G > A), IVS-I-5 (G > C) and codon 44 (-C) accounting for 78.5% of the mutations. This study further illustrates the heterogeneity of the spectrum of β-thalassemia in different parts of Iraq, and provides an essential step to facilitate prenatal diagnosis in the setting of a future national thalassemia prevention program.