Simultaneous analysis of MDR1 C3435T, G2677T/A, and C1236T genotypes by multiplexed mutagenically separated PCR.

P-glycoprotein (PGP) encoded by the multi-drug-resistance 1 (MDR1) gene is a member of the ATP-binding cassette (ABC) transporter family, drug-transporting proteins involved in the bioavailability and pharmacokinetics of various drugs. Several single nucleotide polymorphisms (SNPs) in the MDR1 gene have been identified so far that may influence PGP expression levels and function. Thus, genotyping for MDR1 polymorphisms and determining specific haplotypes may become an important tool in predicting individual susceptibility to developing drug resistance. We developed a new multiplexed allele-specific PCR method based on the principle of mutagenically separated PCR (MS-PCR) for rapid and reliable simultaneous genotyping of the C3435T polymorphism in exon 26 of the MDR1 gene and two additional SNPs (G2677T/A in exon 21 and C1236T in exon 12), which are in linkage disequilibrium with MDR1 C3435T. The accuracy and reliability of this method was confirmed by sequencing the respective regions in the MDR1 gene. This newly developed MDR1 MS-PCR will facilitate fast, accurate and economic analysis of MDR1 genotypes and will provide important information in optimizing individual therapeutic approaches.