CYP2D6 and malaria: That said, we have shown, in a study of CYP2D6 in a Malagasy population, that the unexpected appearance of some alleles associated with diverse populations, including new alleles, new allele frequency patterns, genotype combinations and genotype proportions may reveal population level patterns of special relevance to malaria treatment (Mehlotra et al., 2021; Chan et al., 2022).