A hospital-based cross-sectional study was conducted to determine the allelic and genotype frequencies in the genes encoding for catechol-O-methyltransferase and CYP2D6*10 among healthy volunteers and patients clinically diagnosed with cancer pain. PCR-RFLP was used to identify COMT and CYP2D6*10 genotypes. Allelic frequencies among healthy volunteer Filipinos were 0.83 and 0.17 for the COMT Val and COMT Met alleles, respectively. Calculated frequencies in Hardy-Weinberg equilibrium (HWE) were 73% for COMT Val/Val, 26% for COMT Val/Met, and 1% for COMT Met/Met genotype. For CYP2D6*10, allelic frequencies in HWE among volunteers were 0.46 for the C allele and 0.54 for the T allele. Twenty percent were identified as homozygous for the wild-type C/C genotype, 56% were identified as heterozygous for the C/T genotype, and 24% were identified as homozygous for the T/T variant genotype. No significant differences in COMT and CYP2D6*10 allele frequencies between cancer patients and healthy volunteers were noted. Our data demonstrated that the allele frequencies of COMT and CYP2D6*10 in the Filipino healthy volunteers were similar with other Asians but markedly different from Caucasian populations.
Keywords: Allele frequency; CYP2D6*10; Filipino; catechol-O-methyltransferase; polymorphism.