title: Severe fluoropyrimidine toxicity due to novel and rare DPYD missense mutations, deletion and genomic amplification affecting DPD activity and mRNA splicing.
abstract: Dihydropyrimidine dehydrogenase (DPD) is the initial and rate-limiting enzyme in the catabolism of 5-fluorouracil (5FU). Genetic variations in DPD have emerged as predictive risk factors for severe fluoropyrimidine toxicity. Here, we report novel and rare genetic variants underlying DPD deficiency in 9 cancer patients presenting with severe fluoropyrimidine-associated toxicity. All patients possessed a strongly reduced DPD activity, ranging from 9 to 53% of controls. Analysis of the DPD gene (DPYD) showed the presence of 21 variable sites including 4 novel and 4 very rare aberrations: 3 missense mutations, 2 splice-site mutations, 1 intronic mutation, a deletion of 21 nucleotides and a genomic amplification of exons 9-12. Two novel/rare variants (c.2843T>C, c.321+1G>A) were present in multiple, unrelated patients. Functional analysis of recombinantly-expressed DPD mutants carrying the p.I948T and p.G284V mutation showed residual DPD activities of 30% and 0.5%, respectively. Analysis of a DPD homology model indicated that the p.I948T and p.G284V mutations may affect electron transfer and the binding of FAD, respectively. cDNA analysis showed that the c.321+1G>A mutation in DPYD leads to skipping of exon 4 immediately upstream of the mutated splice-donor site in the process of DPD pre-mRNA splicing. A lethal toxicity in two DPD patients suggests that fluoropyrimidines combined with other therapies such as radiotherapy might be particularly toxic for DPD deficient patients. Our study advocates a more comprehensive genotyping approach combined with phenotyping strategies for upfront screening for DPD deficiency to ensure the safe administration of fluoropyrimidines.
authors.affiliation: Academic Medical Center, University of Amsterdam, Emma Children's Hospital, Departments of Clinical Chemistry, Pediatrics and Clinical Genetics, Laboratory Genetic Metabolic Diseases, Amsterdam, The Netherlands. Electronic address: a.b.vankuilenburg@amc.uva.nl.
authors.forename: André B P
authors.initials: AB
authors.lastname: van Kuilenburg
authors.affiliation: Academic Medical Center, University of Amsterdam, Emma Children's Hospital, Departments of Clinical Chemistry, Pediatrics and Clinical Genetics, Laboratory Genetic Metabolic Diseases, Amsterdam, The Netherlands.
authors.forename: Judith
authors.initials: J
authors.lastname: Meijer
authors.affiliation: Uppsala University, Department of Chemistry, Biomedical Center, S-751 24 Uppsala, Sweden.
authors.forename: Dirk
authors.initials: D
authors.lastname: Maurer
authors.affiliation: Uppsala University, Department of Chemistry, Biomedical Center, S-751 24 Uppsala, Sweden.
authors.forename: Doreen
authors.initials: D
authors.lastname: Dobritzsch
authors.affiliation: Academic Medical Center, University of Amsterdam, Emma Children's Hospital, Departments of Clinical Chemistry, Pediatrics and Clinical Genetics, Laboratory Genetic Metabolic Diseases, Amsterdam, The Netherlands.
authors.forename: Rutger
authors.initials: R
authors.lastname: Meinsma
authors.affiliation: St. Antonius Hospital, Department of Oncology, Nieuwegein, The Netherlands.
authors.forename: Maartje
authors.initials: M
authors.lastname: Los
authors.affiliation: Academic Medical Center, University of Amsterdam, Emma Children's Hospital, Departments of Clinical Chemistry, Pediatrics and Clinical Genetics, Laboratory Genetic Metabolic Diseases, Amsterdam, The Netherlands.
authors.forename: Lia C
authors.initials: LC
authors.lastname: Knegt
authors.affiliation: Academic Medical Center, University of Amsterdam, Emma Children's Hospital, Departments of Clinical Chemistry, Pediatrics and Clinical Genetics, Laboratory Genetic Metabolic Diseases, Amsterdam, The Netherlands.
authors.forename: Lida
authors.initials: L
authors.lastname: Zoetekouw
authors.affiliation: Maastricht University Medical Center, Department of Oncology, Maastricht, The Netherlands.
authors.forename: Rob L H
authors.initials: RL
authors.lastname: Jansen
authors.affiliation: Reinier de Graaf Gasthuis, Department of Clinical Oncology, Delft, The Netherlands.
authors.forename: Vincent
authors.initials: V
authors.lastname: Dezentjé
authors.affiliation: Diakonessenhuis Utrecht, Department of Oncology, Utrecht, The Netherlands.
authors.forename: Lieke H
authors.initials: LH
authors.lastname: van Huis-Tanja
authors.affiliation: Zuyderland Medical Center, Department of Oncology, Sittard-Geleen, The Netherlands.
authors.forename: Roel J W
authors.initials: RJ
authors.lastname: van Kampen
authors.affiliation: Odense University Hospital, Department of Clinical Genetics, Odense C, Denmark.
authors.forename: Jens Michael
authors.initials: JM
authors.lastname: Hertz
authors.affiliation: Academic Medical Center, University of Amsterdam, Emma Children's Hospital, Departments of Clinical Chemistry, Pediatrics and Clinical Genetics, Laboratory Genetic Metabolic Diseases, Amsterdam, The Netherlands.
authors.forename: Raoul C M
authors.initials: RC
authors.lastname: Hennekam
mesh_terms: D000368:Aged; D000964:Antimetabolites, Antineoplastic / Q000009:adverse effects*; D000069287:Capecitabine / Q000009:adverse effects*; D054067:Dihydropyrimidine Dehydrogenase Deficiency / Q000150:complications / Q000235:genetics; D042943:Dihydrouracil Dehydrogenase (NADP) / Q000235:genetics*; D005260:Female; D005472:Fluorouracil / Q000009:adverse effects*; D005784:Gene Amplification; D057809:HEK293 Cells; D006801:Humans; D008297:Male; D008875:Middle Aged; D008958:Models, Molecular; D009154:Mutation; D020125:Mutation, Missense; D009369:Neoplasms / Q000150:complications / Q000188:drug therapy / Q000235:genetics; D000071184:Pharmacogenomic Variants; D012326:RNA Splicing; D017384:Sequence Deletion
chemical_list: D000964:Antimetabolites, Antineoplastic; D000069287:Capecitabine; D042943:Dihydrouracil Dehydrogenase (NADP); D005472:Fluorouracil
keywords: 5-Fluorouracil; Capecitabine; DPYD; Dihydropyrimidine dehydrogenase; Pharmacogenetics; Toxicity