Is the Frameshift Codons 8/9 (+G) [FSC 8/9 (+G)] β-Thalassemia Mutation, Detected by the Polymerase Chain Reaction-Amplification Refractory Mutation System, Really FSC 8/9 (+G)?

Abstract

There are several polymerase chain reaction (PCR)-based approaches for the analysis of known mutations. The PCR-amplification refractory mutation system (PCR-ARMS) is one of the best known and frequently used for the detection of β-thalassemia (β-thal) mutations. However, there is an important point to be considered when searching for the frameshift codon (FSC) 8 (–AA) and FSC 8/9 (+G) mutations. Whereas the primer is specific for the FSC 8 mutation only, the primer for the FSC 8/9 mutation does not discriminate between the FSC 8/9 and FSC 8 mutations. Thus, the high number of FSC8/9 mutations reported in countries like India, Pakistan and some regions of Iran may be due to the use of the FSC 8/9 primer, without taking the FSC 8 mutation into account. It is thus advisable to test for FSC 8 before the FSC 8/9 mutation whenever PCR-ARMS is the method of investigation for these two mutations.