Drug metabolising enzyme polymorphisms in Middle- and Eastern-European Slavic populations.

Inter-individual differences in genes for drug metabolising enzymes and drug transporters are important for understanding efficacy in drug therapy. These differences are important both for the timely estimation of the dosage that should be prescribed to a patient and for the detection of individuals who are prone to side effects from the drug at normal doses. This review summarises the literature concerning the gene variants within nine major drug metabolising enzymes and drug transporters (i.e., CYP1A2, CYP2A6, CYP2C9, CYP2C19, CYP2D6, CYP2E1, CYP3A4, CYP3A5, and MDR-1) in the Middle European region. Notably, published data are not extensive, and most studies were performed on relatively low numbers of individuals. No country has a complete coverage of all genes. Two variants (C2677T/A and C3435T) within the multidrug resistance-1 (MDR-1) gene and variants within the CYP2C9 gene were analysed within most Slavic populations. Nevertheless, even from this incomplete coverage (where unexpectedly high variability was at times seen both between and within populations), it could be extrapolated that the variants within the drug metabolising enzyme genes are present in roughly the same frequencies as in neighbouring countries.