The Frequency of HBB Mutations Among β-Thalassemia Patients in Hamadan Province, Iran

Abstract

β-Thalassemia (β-thal) caused by mutations on the HBB gene is the most common single-gene disorder in the world. In this study, the HBB gene mutation was investigated in Hamadan province, Iran. Forty-one patients referred to a referral hospital were admitted to the study. DNA samples were extracted from peripheral blood. The HBB gene was sequenced in all recruited patients. Eleven mutations and eight polymorphisms were found in the studied patients. IVS-II-1 (G>A) (HBB: c.315+1 G>A) was the most common mutation, accounting for 25.61% of mutant alleles. Other mutations included codon 8 (–AA) (HBB: c.25−26delAA); IVS-I-110 (G>A) (HBB: c.93−21 G>A); codons 8/9 (+G) (HBB: c.27−28insG); IVS-I-1 (G>A) (HBB: c.92 G>A); codon 44 (–C) (HBB: c.135delC); codons 25/26 (+T) (HBB: c.78−79insT); IVS-I-130 (G>C) (HBB: c.93−1 G>C); –28 (A>C) (HBB: c.−78 A>C); codons 36/37 (–T) (HBB: c.112delT) and IVS-I-6 (T>C) (HBB: c.92+6 T>C). According to our findings, the IVS-II-1 mutation has the highest prevalence in Hamadan Province. It was found that the total frequency of the IVS-II-1, codons 25/26 (+T), codons 8/9 (+G), IVS-I-110 and IVS-I-1 mutations was 82.92%. Therefore, given these findings, it is recommended that these five mutations are screened for as a first step in laboratories without sequencing instruments, and that the rest of the gene is subsequently examined.