Pharmacogenomic landscape in Thailand: Array-based profiling and EMR-linked medication exposure

SNP-array genotyping of an 11-gene pharmacogene panel, diplotype-to-phenotype assignment, then linkage with electronic medical record medication exposure to quantify realized actionability.

Pharmacogenomic data remain limited in Thailand and genetics-only surveys rarely quantify realized actionability, the overlap between actionable phenotypes and real-world medication exposure. The authors profiled 4,662 Thai adults using SNP-array data and a pre-specified panel of 11 genes and 26 markers with a hybrid calling policy for diplotype and phenotype assignment, then linked CPIC level A/B gene-drug pairs to hospital electronic medical record prescription and dispensation data. Overall callability reached 98.62 %, exceeding 99 % for most genes but lower for CYP2C19 (95.99 %) and NUDT15 (90.28 %); across the nine phenotype-coded genes, 95.99 % of participants carried at least one CPIC-actionable result (median 2, IQR 2-3). Actionable prevalence among callable individuals was highest for CYP3A5 (58.54 %) and CYP2C19 (56.67 %), followed by ABCG2 (45.10 %) and UGT1A1 (27.37 %). Record linkage identified 1,529 participants (32.58 %) exposed to at least one study medication, omeprazole (n = 658) and statins being the most common, with actionable phenotypes in 55.02 % of omeprazole users for CYP2C19 and 21.95 to 23.05 % of statin users for SLCO1B1.

Synthesis written by Geno'X. For the full original abstract, please refer to the source publication.

The concept of realized actionability is the take-home point: stating that 96 % of the population carries an actionable result does not help size a programme, whereas knowing that one in two omeprazole users has an actionable CYP2C19 phenotype immediately shows where to start. The limitation is that medication exposure is not an endpoint: nothing here shows that returning a genotype would have changed a prescription or prevented an event. Also of note is the 90 % callability for NUDT15, insufficient for a gene whose stake, thiopurine haematological toxicity, does not tolerate missing results.

Analysis by Dr Thibaut Benquey