Beta Thalassemia Mutation Analysis in Fetal Samples for Optimal Mutation Screening Strategy

Abstract

Objective: To determine the frequency of various beta-thalassemia mutations in the prenatal period and ascertain the spectrum of mutations to optimise mutation analysis with cost reduction in testing. Study Design: Cross-sectional study Place and Duration of Study: Department of Molecular Hematology, Armed Forces Institute of Pathology (AFIP)/National University of Medical Sciences (NUMS), Rawalpindi Pakistan from Jul 2021 to Jan 2022. Methodology: Chorionic villus sampling (CVS) was performed at 12-16 weeks of gestation in target couples where both parents were known β-thalassemia carriers. Deoxyribonucleic acid (DNA) was extracted from fetal tissues, and polymerase chain reaction (PCR) was performed, and mutations were analysed with controls on polyacrylamide gel electrophoresis (PAGE). Results: Out of a total of 87 CVS samples, 17(19.5%) showed no mutation, 25(28.7%) had Beta-thalassemia major, and 45 (51.7%) were beta-thalassemia trait (heterozygous). Eight mutations were detected in the study population, and the three most common mutations were Fr 8/9, IVS 1/5 and Cd 15. Comparatively less common mutations included Cd 5, Fr 41/42, Fr 16, IVS 1/1 and Cap+1. Ethnical distribution of these mutations showed high frequency in Pathans and Punjabis compared to Sindhis, Balochis, Saraikis and Kashmiris. Conclusion: The commonly detected prevalent thalassemia mutations must be tested to provide cost-effective facilities in our resource-constrained country. This study will help in future testing strategies and optimisation of mutation analysis in our country.

Keywords

• Amplification refractory mutation system (ARMS)
• Beta-thalassemia
• Chorionic villus sampling (CVS)