title: Prevalence of a common point mutation in the dihydropyrimidine dehydrogenase (DPD) gene within the 5'-splice donor site of intron 14 in patients with severe 5-fluorouracil (5-FU)- related toxicity compared with controls.
abstract: Deficiency of dihydropyrimidine dehydrogenase (DPD), the rate-limiting enzyme in 5-fluorouracil (5-FU) catabolism, has been linked to toxic side effects of 5-FU. The most prominent mutation of the DPD gene resulting in severe DPD deficiency is a G to A mutation in the GT 5'-splice recognition site of intron 14 (exon 14-skipping mutation). The corresponding mRNA lacks exon 14, and the enzymatic activity of the translated DPD protein is virtually absent. We developed a reverse transcription-PCR-based assay suitable for routine identification of the exon 14-skipping mutation and screened a control cohort of 851 Caucasian individuals as well as a cohort of 25 cancer patients reported by their physicians to have suffered from WHO grades 3-4 toxicity upon 5-FU chemotherapy. Within the control cohort, in total, eight heterozygotes were detected (0.94%): one heterozygote in 51 healthy donors, (1.96%); five heterozygotes in 572 hospital patients (0.87%); and two heterozygotes in 228 colorectal tumor patients (0.88%). Among the 25 patients with severe 5-FU-related toxicity, 5 (20%) were heterozygous and 1 (4%) was homozygous for the exon 14-skipping mutation. All six patients had experienced WHO grade 4 myelosuppression. Lethal outcome was seen in the homozygous and two of the heterozygous cases. We conclude that carriers of the DPD exon 14-skipping mutation are at significantly increased risk to experience life-threatening myelosuppression upon 5-FU treatment, even when the allelic status is heterozygous. These data lead us to suggest routine testing for the exon 14-skipping mutation before 5-FU treatment.
authors.affiliation: Department of Internal Medicine II, Friedrich-Schiller-Universität Jena, D-07740 Jena, Germany. m.raida@icrf.icnet.uk
authors.forename: M
authors.initials: M
authors.lastname: Raida
authors.forename: W
authors.initials: W
authors.lastname: Schwabe
authors.forename: P
authors.initials: P
authors.lastname: Häusler
authors.forename: A B
authors.initials: AB
authors.lastname: Van Kuilenburg
authors.forename: A H
authors.initials: AH
authors.lastname: Van Gennip
authors.forename: D
authors.initials: D
authors.lastname: Behnke
authors.forename: K
authors.initials: K
authors.lastname: Höffken
mesh_terms: D000328:Adult; D000368:Aged; D017398:Alternative Splicing / Q000235:genetics; D000964:Antimetabolites, Antineoplastic / Q000009:adverse effects* / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy / Q000201:enzymology / Q000235:genetics; D003110:Colonic Neoplasms / Q000188:drug therapy / Q000201:enzymology / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D003967:Diarrhea / Q000139:chemically induced / Q000473:pathology; D042943:Dihydrouracil Dehydrogenase (NADP); D005091:Exons / Q000235:genetics; D005260:Female; D005472:Fluorouracil / Q000009:adverse effects* / Q000627:therapeutic use; D005787:Gene Frequency; D005838:Genotype; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D007438:Introns / Q000235:genetics*; D007970:Leukopenia / Q000139:chemically induced / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010088:Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D017354:Point Mutation; D012004:Rectal Neoplasms / Q000188:drug therapy / Q000201:enzymology / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012720:Severity of Illness Index; D013274:Stomach Neoplasms / Q000188:drug therapy / Q000201:enzymology / Q000235:genetics; D013280:Stomatitis / Q000139:chemically induced / Q000473:pathology; D013921:Thrombocytopenia / Q000139:chemically induced / Q000473:pathology
chemical_list: D000964:Antimetabolites, Antineoplastic; D018076:DNA, Complementary; D010088:Oxidoreductases; D042943:Dihydrouracil Dehydrogenase (NADP); D005472:Fluorouracil