Molecular Spectrum of Beta-Globin Mutations in Transfusion-Dependent Patients with Thalassemia in Qazvin Province, Iran

Background: Beta thalassemia is a common inherited disease,resulting from one or more of 200 different mutations in the betaglobingene. Qazvin province has attracted migrations of severaldifferent populations due to industrialization during the past fivedecades. The aim of this study was to define the molecular spectrumofbeta-thalassemia mutations in Qazvin province.Methods: Ethylen diamin acetic acid-containing venous bloodsamples were collected from 100 patients with transfusiondependentbeta-thalassemia from the department of Pediatricsin Qods hospital. Age, sex, history, and consanguinity betweenthe parents were recorded by reviewing the patients’files. DNA was isolated from leukocytes using the standardprocedure. Amplification refractory mutation system (ARMS)technique was used for molecular detection of mutations. Directsequencing analysis was applied for DNA samples whenno mutation was detected with ARMS.Results: Of the 200 chromosomes investigated, 11 types of mutationswere identified by ARMS technique while direct sequencingrevealed the remaining alleles (9 types of mutations).Total 20 different mutations discovered by this two-step approach.Abundant alleles (IVS II-1, IVS I-10, FSC 8/9) accountedfor 59.3% of the mutations. IVS II-1 with a frequencyof 31.3 % was the most common while HbS, Cd 74/75 and Cd15, each with a frequency of 0.55%, had the least frequencies.Conclusion: Beta thalassemia mutations are very heterogeneousin Qazvin province. Extensive ethnic and genetic admixture hasresulted in unexpectedly high number of different mutations,most of them similar to that of north and north-western provincesof Iran. Different mutations in this region suggest migration ofchromosomes fromdistant places and genetic admixture