Abstracts

Rationale: Cytochrome P450 (CYP) 2D6 is the principal enzyme responsible for the metabolism of numerous clinically important drugs including phenytoin. CYP2D6*3 and *4 genotypes in CYP2D6 gene are found to be related with poor metabolism of these drugs. We hypothesized that polymorphisms in this gene may possibly be related to drug resistance in epilepsy and investigated these polymorphisms in drug resistant versus drug responsive patients. Methods: DNA samples were obtained from 60 patients aged 2 to 18 years (mean: 9.28 4.96) with drug responsive epilepsy, 59 patients with drug resistant epilepsy aged 2 to 16 years (mean: 6.68 4.21) and 76 healthy subjects. CYP2D6*3 and CYP2D6*4 polymorphisms were determined by polymerase chain reaction followed by melting curve analysis. Results were expressed as genotype and allele frequencies per drug responsive, drug resistant and control subjects and compared by X2 -test. Results: Allele distributions of CYP2D6*3 and CYP2D6*4 were similar among the study groups. Genotype distrubution were also found to be similar among the groups. We could not demonstrate any statistically significant relation with CYP2D6*3 and *4 genotype in drug resistant patients. We also did not observe any significant correlation between the presence of a specific allele frequency and drug resistance. Conclusions: The present study reports the first study of polymorphisms of CYP2D6 gene in intractable epilepsy, which demonstrates that the intractable epilepsy does not possess any association with CYP2D6 genotype and alleles.