Genetic Polymorphisms in CYP2 Gene Family in Bulgarian Individuals and their Clinical Implications

The cytochrome P450 superfamily consists of hemeproteins involved in the detoxication of different xenobiotics, including drugs. The CYP2 gene family is responsible for the metabolism of 80% of the drugs in clinical use. There are considerable interindividual and interethnic variabilities in the rate of drug metabolism as a result of genetic polymorphisms. The goal of our study was to determine the frequency of 10 genetic polymorphisms in CYP2 family genes to give light on the pharmacogenetic defects of the main CYPs, involved in drug metabolism, in Bulgarian individuals. We detected high allele frequency for CYP2D6*10 (0.27), CYP2D6*4 (0.22), and CYP2B6*9 (0.24), followed by CYP2C19*2 (0.14), CYP2C9*3 (0.11) and CYP2C9*2 (0.09). The genotype frequencies were also determined for all investigated variants. In total 47.2% of the analyzed individuals carried CYP2D6 genetic polymorphisms – 5.6% carried a single variant and 41.6% were found to have two or more such variants. Homozygotes for CYP2D6 variants were established among 14% of Bulgarian individuals. Determination of the prevailing pharmacogenetic polymorphisms of the CYPs, most responsible for drug metabolism, will lead to a lower risk of drug toxicity, increased drug efficacy, and drug dose optimization.