Clinical Utility of Short Tandem Repeats (STRs) Haplotyping for Genetic Diagnosis & Screening of Beta Globin Cluster

Jyotsana Gaur, Dr Rashmi Arnold, Dr. Sunil Polipalli, Dr. Somesh Kumar, Dr Seema Kapoor

Abstract: Beta-thalassemia is a genetic disorder caused by mutations in the HBB gene, leading to reduced or absent ?-globin chain production in hemoglobin. In India, ?-thalassemia carrier prevalence ranges from 3% to 10% influenced by ethnic and geographic factors, significantly exceeding the global average reported by WHO (Rund & Rachmilewitz, 2005). This study highlights the clinical utility of short tandem repeats (STRs) analysis to facilitate the birth of unaffected children (Old, 2003; Kapoor et al., 2017). In this research, six short tandem repeat markers closely linked to the beta globin gene were analyzed by using 15 couples carrying ?-thalassemia. A total number of 15 CVS (Chorionic villus sample) tissues were further tested for haplotyping and genetic analysis using Sanger sequencing to confirm diagnosis. Ultimately, 11 of the 15 couples resulted in healthy or asymptomatic children. This study reveals that STR analysis, verified by Sanger sequencing, offers a reliable and practical approach for detecting ?-thalassemia in embryos. This method significantly improves the likelihood of preventing the condition in at-risk pregnancies, thus contributing to reducing the prevalence of ?-thalassemia in the population.

Keywords: Beta thalassemia, Haplotype, STR, Beta globin cluster