Severe fluoropyrimidine toxicity due to novel and rare DPYD missense mutations, deletion and genomic amplification affecting DPD activity and mRNA splicing

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• 作者：André ; B.P. van Kuilenburg^a ; ^{a.b.vankuilenburg@amc.uva.nl} ; Judith Meijer^a ; Dirk Maurer^b ; Doreen Dobritzsch^b ; Rutger Meinsma^a ; Maartje Los^c ; Lia C. Knegt^a ; Lida Zoetekouw^a ; Rob L.H. Jansen^d ; Vincent Dezentjé ; ^e ; Lieke H. van Huis-Tanja^f ; Roel J.W. van Kampen^g ; Jens Michael Hertz^h ; Raoul C.M. Hennekam^a
• 关键词：Dihydropyrimidine dehydrogenase ; DPYD ; 5-Fluorouracil ; Capecitabine ; Pharmacogenetics ; Toxicity
• 刊名：Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：1863
• 期：3
• 页码：721-730
• 全文大小：1301 K
• 卷排序：1863

文摘

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.