title: Diagnosis of dihydropyrimidine dehydrogenase deficiency in a neonate with thymine-uraciluria.
abstract: Dihydropyrimidine dehydrogenase deficiency is an inborn error of pyrimidine metabolism characterised by thymine-uraciluria, convulsive disorders and developmental delay in paediatric patients, and an increased risk of toxicity from 5-fluorouracil treatment. This report is of the first patient with dihydropyrimidine dehydrogenase deficiency diagnosed in Hong Kong. The patient was a 2-day-old male neonate of Pakistani origin who presented with convulsions. Diagnosis was made by gas chromatographic-mass spectrometric detection of thymine-uraciluria and by molecular detection of a G to A point mutation in a 5'-splicing site leading to skipping of exon 14 in the DPYD gene of chromosome location 1q22. The results showed that the patient and his mother were homozygous and the father heterozygous for the splice site mutation. The mother also had thymine-uraciluria but was clinically asymptomatic.
authors.affiliation: Department of Pathology, Princess Margaret Hospital, Princess Margaret Hospital Road, Laichikok, Hong Kong.
authors.forename: K M
authors.initials: KM
authors.lastname: Au
authors.forename: C K
authors.initials: CK
authors.lastname: Lai
authors.forename: Y P
authors.initials: YP
authors.lastname: Yuen
authors.forename: C C
authors.initials: CC
authors.lastname: Shek
authors.forename: C W
authors.initials: CW
authors.lastname: Lam
authors.forename: A Y W
authors.initials: AY
authors.lastname: Chan
mesh_terms: D042943:Dihydrouracil Dehydrogenase (NADP); D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D010088:Oxidoreductases / Q000172:deficiency* / Q000235:genetics; D017354:Point Mutation; D011686:Purine-Pyrimidine Metabolism, Inborn Errors / Q000175:diagnosis* / Q000235:genetics; D011743:Pyrimidines / Q000378:metabolism*; D012640:Seizures / Q000209:etiology; D013941:Thymine / Q000652:urine; D014498:Uracil / Q000652:urine
chemical_list: D011743:Pyrimidines; D014498:Uracil; D010088:Oxidoreductases; D042943:Dihydrouracil Dehydrogenase (NADP); C030986:pyrimidine; D013941:Thymine