Resolving discordant CYP2D6 genotyping results in Thai subjects: Platform limitations and novel haplotypes

• Main Authors: Yaowaluck Hongkaew, Wendy Y. Wang, Roger Gaedigk, Chonlaphat Sukasem, Andrea Gaedigk
• Other Authors: Bumrungrad International Hospital
• Format: Article
• Published: 2022
• Subjects: Biochemistry, Genetics and Molecular Biology; Pharmacology, Toxicology and Pharmaceutics
• Online Access: https://repository.li.mahidol.ac.th/handle/123456789/76154
• Institution: Mahidol University

Aim: Several CYP2D6 Luminex xTAG genotype calls were identified as inconsistent or suspicious among Thai subjects and further characterized to identify the root causes. Material & methods: Forty-eight subjects were followed-up with long-range-PCR, quantitative copy number assays and/or Sanger sequencing. Results: Most of the Luminex-duplication calls were either negative or had hybrid structures involving CYP2D6*36 in various configurations. Ten samples were inaccurately called as CYP2D6*2, *29 or *35 alleles. Sequencing revealed three novel haplotypes, CYP2D6*142, *143 and *144 of which two are nonfunctional. Conclusion: The Luminex platform produced a relatively high number of false genotype calls for Thai subjects. Our findings underscore the need for the systematic characterization of the CYP2D6 locus in diverse populations and rigorous platform validation.