Analysis of beta globin gene mutations in Diyarbakir

Abstract

Objectives Hemoglobin disorders are quite heterogeneous in the Turkish population. Up to now, more than forty different beta thalassemia mutations and 60 hemoglobin variants have been characterized in the country. The aim of this study was to investigate genetic heterogeneity of HBB gene mutations in patients and their parents at Southeastern Anatolia in Turkey. Methods Genomic DNA was isolated from 145 thalassemic patients' blood samples and their parents in this study. Ten different HBB gene mutations HBB:c.-80T>A, HBB:c.17_18delCT, HBB:c.25_26delAA, HBB:c.92+1G>A, HBB:c.92+5G>C, HBB:c.92+6T>C, HBB:c.93-21G>A, HBB:c.135delC, HBB:c.315+1G>A, HBB:c.316-106C>G were screened by amplification refractory mutation system. Four Hb variants and some rare beta thalassemia mutation were characterized by DNA sequencing. Results In this study, 97 homozygous and 48 compound heterozygous thalassemic patients were diagnosed by molecular genetic analyses. As a results, 18 beta-thalassemia mutations and four abnormal hemoglobins; HBB:c.20A>T, HBB:c.364G>C, HBB:c.34G>A and HBB:c.208G>A were detected at Dicle University Hospital. Conclusions In the results, HBB:c.93-21G>A is the most common mutation in the region. Three mutations [(HBB:c.93-21G>A), (HBB:c.25_26delAA) and (HBB:c.135delC)] account for about 58 per cent of all the point mutations. Except HBB:c.20A>T and HBB:c.364G>C, two silent Hb variants (HBB:c.34G>A and HBB:c.208G>A) were detected in this study. Hb Hamilton [beta 11 (GTT>ATT) Val>Ile] was seen first time in Turkey.