Open AccessDihydropyrimidine dehydrogenase gene variation and severe 5-fluorouracil toxicity: a haplotype assessment
Author(s) -
Ursula Amstutz,
Simone Farese,
Stefan Aebi,
Carlo R. Largiadèr
Publication year - 2009
Publication title -
pharmacogenomics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.541
H-Index - 91
eISSN - 1744-8042
pISSN - 1462-2416
DOI - 10.2217/pgs.09.28
Subject(s) - dpyd , haplotype , dihydropyrimidine dehydrogenase , nonsynonymous substitution , genetics , biology , exon , genetic variation , pharmacogenetics , pharmacogenomics , mutation , coding region , fluorouracil , gene , genotype , chemotherapy , thymidylate synthase , genome
Aims: The importance of polymorphisms in the dihydropyrimidine dehydrogenase gene (DPYD) for the prediction of severe toxicity in 5-fluorouracil (5-FU)-based chemotherapy is still unclear. This study aims to assess the predictive value of DPYD variation with respect to previously described DPYD variants for 5-FU toxicity. It represents the first analysis of the gene at the haplotype level, also capturing potentially important genetic variation located outside the coding regions of DPYD. Materials & methods: The entire coding sequence and exon-flanking intronic regions of DPYD were sequenced in 111 cancer patients receiving fluoropyrimidine-based chemotherapy. DPYD haplotypes were inferred and their associations with severe 5-FU toxicity were assessed. Results: None of the previously described deleterious variants (IVS14+1G>A, c.2846A>T and c.1679T>G) were detected in 24 patients who experienced severe 5-FU toxicity. A potential association was observed between a haplotype containing three novel intronic polymorphisms (IVS5+18G>A, IVS6+139G>A and IVS9–51T>G) and a synonymous mutation (c.1236G>A), which was observed five- out of eight-times in patients with severe adverse effects. Conclusion: The association of a haplotype containing no nonsynonymous or splice-site polymorphisms indicates that additional important genetic variation may be located in noncoding gene regions. Furthermore, a comparison with other studies suggests that the relative importance of particular DPYD mutations (IVS14+1G>A and c.2846A>T) for predicting severe 5-FU toxicity differs geographically across Europe.