Furthermore, our data suggested a prevalence of reduced DPD function alleles in Europeans of 7.6%, again in good agreement with the results of a prospective study in the Netherlands, which reported 8% of patients to carry at least one functionally relevant DPYD variant allele.12 A previous study indicated that DPD deficiency due to DPYD*2 A was very high in Sweden with MAF = 3.5%,59 while our analysis of 1000 Swedish genomes showed lower frequencies of 0.8%. The gene discussed is DPYD; the disease is dihydropyrimidine dehydrogenase deficiency.