Detection of β-Thalassemia mutations using TaqMan single nucleotide polymorphism genotyping assays

Aims: Sickle-cell anemia and β-thalassemia are two of the most common autosomal recessive disorders in the developing world. The severity of the problem and the pressure it exerts on the health services in the Kingdom of Saudi Arabia forced the introduction of a national premarital screening program to lessen its impact on the society. Furthermore, a significant effort has been exerted in the elucidation of the genetic causes of such diseases to facilitate diagnosis and detection of carriers. Methods: We have designed and validated the use of custom TaqMan® genotyping assays for the rapid detection of IVS-I-1 (G>A), IVS-I-5 (G>C), codon 39 (C>T), and IVS-I-110 (G>A) mutations in transfusion-dependent β-thalassemia patients' cohort. Results: We demonstrated that IVS-I-5 (rs33915217) is the most common single-nucleotide variant in our cohort, with the variant allele constituting 26% of the total alleles investigated. However, this variant was not found in 352 alleles screened from buccal swab DNA obtained from healthy volunteers. Conclusion: The TaqMan single nucleotide polymorphism (SNP) genotyping assays are a rapid, accurate, and cost-effective method for the initial screening of β-thalassemia cases, which will minimize the need for direct sequencing of the HBB gene, thus reducing detection costs and increasing throughput.