CYP2D6 phenotypes among Malays in Malaysia

Area of Science:

• Pharmacogenetics
• Drug Metabolism

Background:

• The CYP2D6 gene is highly polymorphic and crucial for metabolizing numerous drugs.
• Previous studies indicated a higher prevalence of CYP2D6 poor metabolism (PM) phenotype in Malays compared to Chinese.
• Understanding CYP2D6 variations in Malays is important due to intermarriages and potential implications in drug response and environmentally-induced diseases.

Purpose of the Study:

• To investigate debrisoquine metabolism phenotypes in a cohort of healthy Malay volunteers.
• To characterize the CYP2D6 genetic polymorphism within the Malay population.

Main Methods:

• Administration of debrisoquine to 51 healthy Malay participants.
• Utilizing High-Performance Liquid Chromatography (HPLC) to quantify urinary debrisoquine and 4-hydroxydebrisoquine.
• Calculation of debrisoquine metabolic ratios (MR) to determine metabolic phenotypes.

Main Results:

• Debrisoquine metabolic ratios (MR) exhibited wide variability within the study population.
• Probit analysis identified distinct population subsets based on MR.
• The frequency distribution of MR showed a rightward shift, less pronounced than observed in the Chinese population, with 2 poor metabolizers and 1 ultra-rapid metabolizer identified.

Conclusions:

• The debrisoquine metabolic profile in Malays is genetically distinct from that of the Chinese population.
• Malay individuals appear to possess an intermediate metabolic profile between Europeans and Chinese concerning CYP2D6 polymorphism.
• Further research comparing CYP2D6 genotypes across related ethnic groups is recommended to elucidate these pharmacogenetic differences.