Rapid Antenatal Diagnosis of β-Thalassemia in Chinese Caused by the Common 4-BP-Deletion in Codons 41/42 Using High-Resolution Agarose Gel Electrophoresis and Heteroduplex Detection

The 4-bp deletion in codons 41/42 (-TTCT) in the β-globin gene is a common mutation that causes β-thalassemia in Chinese. A simple method, which involved PCR amplification of the relevant region, was used for the antenatal diagnosis of a fetus at risk for this mutation. The fetal PCR product showed a single fragment of normal size on MetaPhor gel. The homozygous normal status was further confirmed by the generation of heteroduplexes only after addition of homozygous mutant DNA.