Clinical, biochemical and genetic findings in two siblings with a dihydropyrimidinase deficiency.
Mol Genet Metab
; 91(2): 157-64, 2007 Jun.
Article
em En
| MEDLINE
| ID: mdl-17383919
ABSTRACT
Dihydropyrimidinase (DHP) is the second enzyme of the pyrimidine degradation pathway and it catalyses the ring opening of 5,6-dihydrouracil and 5,6-dihydrothymine to N-carbamyl-beta-alanine and N-carbamyl-beta-aminoisobutyric acid, respectively. To date, only nine individuals have been reported suffering from a complete DHP deficiency. We report two siblings presenting with strongly elevated levels of 5,6-dihydrouracil and 5,6-dihydrothymine in plasma, cerebrospinal fluid and urine. One of the siblings had a severe delay in speech development and white matter abnormalities, whereas the other one was free of symptoms. Analysis of the DHP gene (DPYS) showed that both patients were compound heterozygous for the missense mutation 1078T>C (W360R) in exon 6 and a novel missense mutation 1235G>T (R412M) in exon 7. Heterologous expression of the mutant enzymes in Escherichia coli showed that both missense mutations resulted in a mutant DHP enzyme without residual activity. Analysis of the crystal structure of eukaryotic DHP from the yeast Saccharomyces kluyveri and the slime mold Dictyostelium discoideum suggests that the W360R and R412M mutations lead to structural instability of the enzyme which could potentially impair the assembly of the tetramer.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Amidoidrolases
Tipo de estudo:
Diagnostic_studies
/
Prognostic_studies
Limite:
Animals
/
Child, preschool
/
Humans
/
Male
Idioma:
En
Revista:
Mol Genet Metab
Assunto da revista:
BIOLOGIA MOLECULAR
/
BIOQUIMICA
/
METABOLISMO
Ano de publicação:
2007
Tipo de documento:
Article
País de afiliação:
Holanda