[Severe 5-fluorouracil toxicity in a woman treated for breast cancer with concurrent osteogenesis imperfecta and dehydrogenase deficiency].

Dihydropyrimidine dehydrogenase (DPD) is the principal enzyme involved in the catabolism of 5 fluorouracil (5 FU). The clinical importance of DPD has recently been demonstrated wit the identification of rare cases presenting a severe toxicity to 5 FU related to proven DPD deficiency. We report a new case in a patient with concurrent congenital osteogenesis imperfecta. We were surprised to find another similar association reported by Lyss. It is tempting to speculate that DPD activity may be abnormally regulated in osteogenesis imperfecta patients.