Real-time quantitative PCR analysis for α-thalassemia-1 of Southeast Asian type deletion in Taiwan

Since homozygosity of the α‐thalassemia‐1 of Southeast Asian (SEA) type deletion results in hydrops fetalis, a novel protocol based on the real‐time quantitating polymerase chain reaction (PCR) technique has been developed to quantify the intact and aberrant α‐globin genes in adults. The ratio of the normal/SEA‐bearing α‐globin genes was expressed in cycle threshold (CT) values. Theoretically, a relative ratio of one to one was anticipated in individuals carrying the SEA type deletion. Twenty‐five heterozygous and 20 normal cases were analyzed retrospectively with this protocol. Data showed that the CT values for the intact α‐globin gene allele and the allele bearing the SEA type deletion in carriers were 28.74±1.49 and 26.46±2.05, respectively. Therefore, the ratio of normal/SEA type deletion‐bearing α‐globin genes in the carriers was 1.09±0.043. No ambiguous results were observed from other less common genotypes associated with α‐thalassemia, such as the Philippine type deletion. Based on the results, we concluded that this protocol could provide a rapid method to mass screen carriers with α‐thalassemia‐1 of SEA type deletion in this region.