Cytochrome P450 polymorphism--molecular, metabolic, and pharmacogenetic aspects. IV. Application of long polymerase chain reaction for identification of CYP2D6 gene duplication

Abstract

In the human organism 58 cytochrome P450 (CYP) isoenzymes belonging to 18 families have been described. Isoenzyme CYP2D6 is an important human xenobiotic-metabolizing enzyme. CYP2D6 biotransforms a significant number of drugs, widely used in clinical practice, such as antidepressants, neuroleptics, antiarrhythmics, analgesics, antiemetics and anticancer agents. The occurrence of polymorphic variants of the enzyme results in different metabolic capacity ranging from poor to ultrarapid. Ultrarapid metabolizer phenotype explains lack of response and decreased levels of drugs which are metabolized by CYP2D6. Therefore, the identification of ultrarapid metabolizers as potential non-compliance cases requiring dose adjustment, has serious clinical importance. In this study we evaluate a long-PCR procedure for detecting CYP2D6 gene duplication.