Mutation Analysis of Hemoglobin Subunit Beta (HBB) Gene in Beta-Thalassemia Patients in North Karnataka Population

Abstract

Introduction: Beta-thalassemia is among the most frequent monogenic disorders around the globe. Over 100,000 children worldwide require regular transfusion due to beta-thalassemia, with India accounting for about 10% of cases and a carrier rate of 5-17%. The disorder is caused by mutations in the beta-globin (HBB) gene, especially in exon 3, which affects beta-globin production and leads to sever anemia. Genetic testing is crucial for prenatal diagnosis, carrier screening, and counseling to manage and prevent the disease.
Material and Methods: The study was conducted on 47 beta-thalassemia patients aged 6 months to 18 years, with ethical approval. After informed consent, 1ml blood sample were collected. DNA was extracted using the Kit, and Primers targeting exon 3 of the HBB gene were design. PCR amplification was performed with specific cycling conditions, and products verified by gel electrophoresis.
Results: Sequencing identified a likely benign homozygous intronic variant g.5511G>C (rs107686883). Mutation analysis in 47 patients revealed heterozygous mutations g.5401G>A.
Conclusion: Missense mutations, especially G>T transition, were common in HBB exon 3 of thalassemia major patients. Molecular screening and genetic counseling are vital to reduce disease impact. G>A mutation caused severe early disease, G>T moderate severity, and compound heterozygosity showed intermediate symptoms.