A Nested Asymmetric PCR Melting Curve Assay for One-Step Genotyping of Nondeletional α-Thalassemia Mutations

Abstract

A rapid DNA-based assay is essential for clinical diagnosis and mass screening in thalassemia-prevention programs. Because of high homology and guanine-cytosine-rich and complex second structure of α-globin genes, it is rather difficult to develop a feasible and simple method for α-thalassemia genotyping. In this study, a strategy of nested asymmetric PCR melting curve analysis was designed to tackle these factors and ensure sensitivity and accuracy. Herein, a novel one-step assay for genotyping of nondeletional α-thalassemia mutations, including hemoglobin (Hb) Westmead (HBA2: c.369C>G), Hb Quong Sze (HBA2: c.377T>C), Hb Constant Spring (HBA2: c.427T>C), CD30 (HBA2: c.91-93delGAG), and CD31 (HBA2: c.95G>A) in a single closed tube, was established and evaluated. All five mutations were accurately determined with the concordance rate of 100% in a blind analysis of 255 genotype-known samples and 1250 clinical samples. In conclusion, this assay is useful for rapid and reliable genotyping of nondeletional α-thalassemia mutations in clinical practice. Especially, the strategy may have the potential to be a versatile scheme for rapid genotyping of other gene mutations because of its high throughput, sufficient stability, low cost, and simple operation.