Background. Xenobiotic-metabolizing enzymes are widely polymorphic and confer interindividual variation in the ability to detoxify carcinogens or to activate pro-carcinogens. Many of the clinical important drugs are CYP2D6 substrates. CYP2D6 polymorphic variants affect enzyme function causing different drug responses. In white European population in CYP2D6 gene there most often found substitution G1934A (allele *4) on the line between intron 3 and exon 4, the presence of which leads to incorrect mRNA splicing resulting in a shift of reading frame, termination of translation, and generation of defective protein product lacking enzymatic activity. This mutated allele shows a very high degree of inter individual variability. We have studied the genotypes frequency of polymorphic variant G1934A of CYP2D6 gene in Ukrainian population.
Aim. The present study aimed to determine the most common mutated allele *4 (G1934A) of CYP2D6 gene in the Ukrainian population of 918 unrelated subjects.
Materials and methods. The method of PCR-RFLP (polymerase chain reaction — restriction fragment length polymorphism) has been used for determination of polymorphic variant G1934A of CYP2D6 gene. The data were analyzed with the use of Statistica 6.0 program. For determination of significance of differences between genotype frequencies in compared groups, standard c2 criterion was used.
Results. The frequency of investigated genotypes were: *1*1 (1934GG) — 64.93%; *1*4 (1934GA) — 31.26% and *4*4 (1934AA) — 3.81%. It was proved no differences in the distribution of genotypes for the polymorphic variant G1934A of CYP2D6 gene in individuals of different genders and people of different age groups. The comparative evaluation of the genotypes frequency of polymorphic variant G1934A of CYP2D6 gene in the Ukrainian population and other ethnic groups. These frequencies were not significantly different (p>0.05) from those of Caucasians and significantly different (p<0.05) from those obtained by other authors for Orientals.