Journal Article

Intragenic deletions and a deep intronic mutation affecting pre-mRNA splicing in the dihydropyrimidine dehydrogenase gene as novel mechanisms causing 5-fluorouracil toxicity

Maartense, Ed, Dobritzsch, Doreen, van Kuilenburg, André B. P., Gross, Eva, Etienne-Grimaldi, Marie-Christine, Mul, Adri N. P. M., Meinsma, Rutger, Mannens, Marcel M. A. M., Hennekam, Raoul C. M., Maring, Jan Gerard, Meijer, Judith, Kiechle, Marion, Klümpen, Heinz-Josef, Derleyn, Veerle A., Schmid, Veronika, Milano, Gérard, Vijzelaar, Raymon

2010

Overview

Dihydropyrimidine dehydrogenase (DPD) is the initial enzyme acting in the catabolism of the widely used antineoplastic agent 5-fluorouracil (5FU). DPD deficiency is known to cause a potentially lethal toxicity following administration of 5FU. Here, we report novel genetic mechanisms underlying DPD deficiency in patients presenting with grade III/IV 5FU-associated toxicity. In one patient a genomic DPYD deletion of exons 21–23 was observed. In five patients a deep intronic mutation c.1129–5923C>G was identified creating a cryptic splice donor site. As a consequence, a 44 bp fragment corresponding to nucleotides c.1129–5967 to c.1129–5924 of intron 10 was inserted in the mature DPD mRNA. The deleterious c.1129–5923C>G mutation proved to be in cis with three intronic polymorphisms (c.483 + 18G>A, c.959–51T>G, c.680 + 139G>A) and the synonymous mutation c.1236G>A of a previously identified haplotype. Retrospective analysis of 203 cancer patients showed that the c.1129–5923C>G mutation was significantly enriched in patients with severe 5FU-associated toxicity (9.1%) compared to patients without toxicity (2.2%). In addition, a high prevalence was observed for the c.1129–5923C>G mutation in the normal Dutch (2.6%) and German (3.3%) population. Our study demonstrates that a genomic deletion affecting DPYD and a deep intronic mutation affecting pre-mRNA splicing can cause severe 5FU-associated toxicity. We conclude that screening for DPD deficiency should include a search for genomic rearrangements and aberrant splicing.

• Publisher: Springer-Verlag,Springer,Springer Nature B.V
• Subject: 5-Fluorouracil / Adult / Aged / Analysis / Antimetabolites, Antineoplastic - toxicity / Biological and medical sciences / Biomedical and Life Sciences / Biomedicine / Cancer / Classical genetics, quantitative genetics, hybrids / Comparative Genomic Hybridization / dehydrogenase / Dehydrogenases / Dihydrouracil Dehydrogenase (NADP) - genetics / Dihydrouracil Dehydrogenase (NADP) - metabolism / Enzymes / Exons / Female / Fluorouracil / Fluorouracil - toxicity / Fundamental and applied biological sciences. Psychology / Gene deletion / Gene Function / Gene polymorphism / Gene Rearrangement / Genetic aspects / Genetics of eukaryotes. Biological and molecular evolution / genomics / Haplotypes / Human / Human Genetics / Humans / Introns / Male / Messenger RNA / Metabolic Diseases / Middle Aged / Molecular Medicine / mRNA / Mutation / Mutation, Missense / Nucleotides / Oncology / Original Investigation / Patients / Polymerase Chain Reaction / Polymorphism, Genetic / RNA Splicing / RNA, Messenger / Sequence Analysis, DNA / Sequence Deletion / Splicing / Toxicity