Polygenic risk scores in pharmacogenomics: methodological challenges, current applications, and perspectives for clinical implementation

AI Summary

PRS capture cumulative polygenic contributions to drug response, offering probabilistic risk stratification beyond single-gene pharmacogenetics.
Key methodological challenges include limited drug-exposed sample sizes, heterogeneous phenotype definitions, ancestry-related portability issues, and incomplete representation of complex pharmacogenes.
Clinical implementation requires standardised methods, multi-ancestry validation, integration of rare high-impact ADME variants, and clearer regulatory pathways.

AI Summary

Polygenic risk scores (PRS) offer a framework to capture cumulative effects across pharmacokinetic, pharmacodynamic, and disease-related pathways, enabeling probabilistic risk stratification beyond monogenic models.

This review summarizes the current status of PRS in pharmacogenomics (PGx-PRS), highlighting key challenges including limited sample sizes of drug-exposed cohorts, heterogeneous phenotype definitions, ancestry-related portability issues, and incomplete representation of complex pharmacogenes such as CPY2D6.

Current applications are discussed across cardiovascular, psychiatric, and oncological settings, where PRS show emerging potential for benefit-risk stratification but remain insufficiently validated for routine care.

Basic summary

Med Genet. 2026 Jul 8;38(3):221-229. doi: 10.1515/medgen-2026-3013. eCollection 2026 Jul.

ABSTRACT

Inter-individual variability in drug response remains a major challenge in clinical pharmacology. While clinical pharmacogenetics is largely based on actionable single-gene variants, increasing GWAS evidence indicates that many drug-response phenotypes are polygenic. Polygenic risk scores (PRS) offer a framework to capture cumulative effects across pharmacokinetic, pharmacodynamic, and disease-related pathways, enabeling probabilistic risk stratification beyond monogenic models. This review summarizes the current status of PRS in pharmacogenomics (PGx-PRS), highlighting key challenges including limited sample sizes of drug-exposed cohorts, heterogeneous phenotype definitions, ancestry-related portability issues, and incomplete representation of complex pharmacogenes such as CPY2D6. Current applications are discussed across cardiovascular, psychiatric, and oncological settings, where PRS show emerging potential for benefit-risk stratification but remain insufficiently validated for routine care. Clinical implementation will require standardized methodologies multi-ancestry validation, integration with rare-high impact ADME (Absorption, Distribution, Metabolism, and Excretion) variants, and clearer regulatory pathways. With these advances, PGx-PRS may become clinically relevant tools for precision prescribing and drug development.

PMID:42416881 | PMC:PMC13340549 | DOI:10.1515/medgen-2026-3013

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