Investigation of CYP2D6 (*2,*3,*4,*7,*10,*41) gene polymophisms in pediatric cardiology patients

The CYP2D6 enzyme metabolizes several antiarrhythmic, antihypertensive drugs, especially beta-blockers. CYP2D6 genetic polymorphisms can change the efficacy and toxicity of these cardiac drugs. On the other hand, in pediatric cardiac patients, the practical significance of CYP2D6 genetic polymorphisms studied only in a few studies. This study aimed to evaluate CYP2D6 gene polymorphisms (*2, *3, *4, *7, *10 and *41) in these patients, prospectively. Blood samples (2 ml) were taken from 200 patients who applied to Afyonkarahisar Health Sciences University, Faculty of Medicine, Pediatric Cardiology Clinic. CYP2D6 enzyme gene polymorphisms (*2, *3, *4, *7, *10, and *41) were determined by using Polymerase Chain Reaction (PCR) amplification DNA Sequence Analysis methods. We found that 81.5% of the cases were normal metabolizers (NM), 16% were intermediate metabolizers (IM), and 2.5% were poor metabolizers (PM). The most common alleles were found to be *1 (61.75%), *2 (11%), *3 (10.75%), and *10 (10.25%), respectively. Of the 5 patients using beta-blockers and risperidone, 4 were found to be NM and 1 was IM. No changes in drug doses were required. The CYP2D6*3 allele with loss of enzyme function was determined as the most common mutant allele in this study. However, the frequency distributions of the PM (2.50%) and IM (16%) phenotypes in our study population differed markedly from the frequency distributions of the PM (7.5%) and IM (6%) phenotypes observed in the Caucasian population (p<0.02). The fact is that 18.5% of the cases in which changes in enzyme activity were detected in our study. It would be beneficial in terms of determining CYP2D6 gene changes in pediatric cardiac patients before treatment.