BRIEF RESEARCH REPORT article
Front. Genet.
Sec. Pharmacogenetics and Pharmacogenomics
Allelic diversity of the pharmacogenes CYP2D6 and CYP2C19 in Māori from Te Tairāwhiti, Aotearoa New Zealand
Leonie Hitchman 1
Te Whetu Aarahi Kerekere 1
Allison Lynn Miller 1
Elizabeth Goodin 2
Caroline Koia 3
Huti Watson 3
Frances King 3
Stephen Robertson 2
Phillip Wilcox 4
Martin A Kennedy 1
1. Department of Pathology and Biomedical Science, University of Otago Christchurch, Christchurch, New Zealand
2. Department of Womens and Childrens Health, University of Otago, Dunedin, New Zealand
3. Ngati Porou Oranga, Gisborne, New Zealand
4. Department of Mathematics and Statistics, University of Otago, Dunedin, New Zealand
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Abstract
CYP2C19 and CYP2D6 are two important pharmacogenes responsible for metabolising a wide range of medications. Both genes exhibit a high level of variation, which can lead to variable activity of the enzymes they encode, with risks of adverse drug reactions and treatment failure. Understanding this variation is therefore of great importance, but the full extent of variability in these genes is not yet documented, particularly for understudied populations. We employed targeted nanopore sequencing to identify genetic variants within CYP2C19 and CYP2D6 for a group of Māori individuals, largely affiliated with the Ngāti Porou iwi from Te Tairāwhiti (Gisborne), Aotearoa New Zealand. 135 CYP2D6 and 73 CYP2C19 genotypes were sequenced, with metaboliser phenotypes inferred for the majority of participants. CYP2D6 normal metabolisers make up 54% of the cohort and 45% of the cohort are CYP2C19 intermediate metabolisers. Nearly 20% had an uncertain CYP2D6 activity due to the prevalence of CYP2D6*71, which is of unknown functional impact. Understanding the extent of variation in these genes should contribute to equitable application of pharmacogenetic testing in Aotearoa New Zealand.
Summary
Keywords
ancestry, CYP2C19, CYP2D6, diversity, drug metabolism (human and animal), drug response, Indigeneous, nanopore sequencing
Received
17 July 2025
Accepted
19 February 2026
Copyright
© 2026 Hitchman, Kerekere, Miller, Goodin, Koia, Watson, King, Robertson, Wilcox and Kennedy. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Martin A Kennedy
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