The human multidrug resistance gene (<em>MDR1</em>) is encoding the transmembrane transporter P-glycoprotein (P-gp) which plays an important role in the efflux of various drugs and thus is potentially influencing the drug-treatment outcome. It has been indicated that the level of P-gp activity may be affected by the presence of single nucleotide polymorphisms (SNP) in the gene which led to the studies estimating <em>MDR1</em>-SNP frequencies in various populations. Here, we have investigated the occurrence of seven SNP in the <em>MDR1</em> gene for the first time in Slovak population using multiplex SNaPshot genotyping method. The allelic frequencies of the most common gene variants, i.e. 1236C>T, 2677G>T, 2677G>A and 3435C>T were estimated to be 42.5%, 43.5%, 2%, and 44.5%, respectively. We found that the most prevalent haplotype in Slovak population is 1236C-2677G-3435C occurring in 42.2% of individuals. Our preliminary data show that it is reasonable and feasible to utilize <em>MDR1</em> genotypes and haplotypes in Slovak patients, e.g. those with acute myeloid leukemia, in order to adjust the individual effective drug dosage and predict the patient's response to the treatment as well as the treatment outcome.
Keywords: MDR1 gene, P-glycoprotein, polymorphisms, MDR1 haplotypes, Slovak population.