Abstract
The enzyme cytochrome P450 2D6 (CYP2D6) metabolises approximately 25% of commonly prescribed drugs, including analgesics, anti-hypertensives, and anti-depressants, among many others. Genetic variation in drug metabolising genes can alter how an individual responds to prescribed drugs, including predisposing to adverse drug reactions. The majority of research on the
CYP2D6
gene has been carried out in European and East Asian populations, with many Indigenous and minority populations, such as those from Oceania, greatly underrepresented. However, genetic variation is often population specific and analysis of diverse ethnic groups can reveal differences in alleles that may be of clinical significance. For this reason, we set out to examine the range and frequency of
CYP2D6
variants in a sample of 202 Māori and Pacific people living in Aotearoa (New Zealand). We carried out long PCR to isolate the
CYP2D6
region before performing nanopore sequencing to identify all variants and alleles in these samples. We identified twelve variants which have previously not been reported in the PharmVar
CYP2D6
database, three of which were exonic missense variations. Six of these occurred in single samples and one was found in 19 samples (9.4% of the cohort). The remaining five variants were identified in two samples each. Identified variants formed twelve new
CYP2D6
suballeles and four new star alleles, now recorded in the PharmVar database. One striking finding was that
CYP2D6*71
, an allele of uncertain functional status which has been rarely observed in previous studies, occurs at a relatively high frequency (8.9%) within this cohort. These data will help to ensure that
CYP2D6
genetic analysis for pharmacogenetic purposes can be carried out accurately and effectively in this population group.