Simultaneous allele-specific amplification: a strategy using modified primer-template mismatches for SNP detection--application to prothrombin 20210A (factor II) and factor V Leiden (1691A) gene mutations.
BACKGROUND: Inherited thrombophilia is caused by mutations in genes central to the clotting cascade. Analysis of the factor V Leiden (FVL) and prothrombin G20210A mutations are the most prevalent in thrombophilia. METHODS AND RESULTS: We have optimized an allele-specific PCR assay for the simultaneous detection of both wild-type and mutant alleles. This method is adapted for clinical use with the FVL and prothrombin G20210A assays and is significant in its intentional use of nucleotide mismatches at the 3' end of allele-specific primers. Two internal allele-specific primers are designed to amplify in opposite directions on opposite strands that reduce differential amplification. Our results show concordance with methods involving PCR with restriction endonuclease digestion, yet are simpler to perform. CONCLUSION: The simultaneous allele-specific amplification method allows simultaneous detection of wild-type and mutant alleles by PCR using four distinct primers. Nucleotide mismatches in the primers reduce competitive amplification.