Genetic Determinants of β-Thalassemia Intermedia in Pakistan

Abstract

This study covers the molecular characterization of clinically diagnosed β-thalassemia intermedia (β-TI) patients in Pakistan. Blood samples of β-TI patients were collected from all four provinces of Pakistan throughout the period of 2011-2013. The study was carried out using allele-specific primers through polymerase chain reaction or sequencing to determine both α- and β-thalassemia (α- and β-thal) mutations, and restriction enzymes for the characterization of β-globin gene arrangements. In a total of 63 patients, the IVS-I-5 (G > C) was the most frequent mutation (33.88%). The codon 30 (G > A) and IVS-II-1 (T > C) mutations were found only in the Punjabi ethnic group, while the codon 30 (G > C) and Hb S (HBB: c.20A > T) mutations were found only in the Pashtoon and Sindhi ethnic groups, respectively. In case of α-globin genotypes, 44 patients were normal (αα/αα), six patients carried the αα/–α^3.7 genotype, 12 patients carried the −α^3.7/−α^3.7 genotype, while one patient had the αα/ααα^{anti 3.7} genotype. We found that haplotype I was the most frequent, mostly associated with the codons 8/9 (+G) mutation, while the Saudi haplotype was found only with Hb S.

• Haplotype
• hemoglobin (Hb)
• mutation
• polymorphism
• thalassemia

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.

Supplementary material available online

Supplementary Table 1 and Figure 1