Mutations in the pterin-4alpha-carbinolamine dehydratase (PCBD) gene cause a benign form of hyperphenylalaninemia

Four patients with primapterinuria, postulated to be due to pterin-4alpha-carbinolamine dehydratase (PCD) deficiency, were diagnosed by biochemical and DNA analysis. All four patients presented in the neonatal period with hyperphenylalaninemia, and elevated neopterin and decreased biopterin levels i...

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Bibliographic Details
Published in:Human genetics 1998-08, Vol.103 (2), p.162-167
Main Authors: Thöny, B, Neuheiser, F, Kierat, L, Rolland, M O, Guibaud, P, Schlüter, T, Germann, R, Heidenreich, R A, Duran, M, de Klerk, J B, Ayling, J E, Blau, N
Format: Article
Language:English
Subjects:
Amino Acid Metabolism, Inborn Errors - enzymology
Amino Acid Metabolism, Inborn Errors - genetics
Female
Humans
Hydro-Lyases - genetics
Hydro-Lyases - metabolism
Infant, Newborn
Male
Mutation
Phenylalanine - metabolism
Phenylketonurias - enzymology
Phenylketonurias - genetics
Pterins - urine
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Summary:Four patients with primapterinuria, postulated to be due to pterin-4alpha-carbinolamine dehydratase (PCD) deficiency, were diagnosed by biochemical and DNA analysis. All four patients presented in the neonatal period with hyperphenylalaninemia, and elevated neopterin and decreased biopterin levels in the urine. These symptoms are common to 6-pyruvoyltetrahydropterin synthase deficiency and thus there is a danger of misdiagnosis. In addition, all four patients had elevated urinary excretion of primapterin (7-biopterin), the only persistent biochemical abnormality. Analysis of fibroblast DNA from the patients identified the following mutations in the PCBD gene: one patient homozygous for the missense mutation E96K and one homozygous for the nonsense mutation Q97X, both in exon 4; one compound heterozygote with the mutations E96K and Q97X; and one patient with two different homozygous mutations: E26X in exon 2 and R87Q in exon 4. In two families, the parents were investigated and found to be obligate heterozygotes for particular mutations. One sibling was found to be unaffected. These results further substantiate the idea that primapterinuria is associated with mutations in the PCBD gene.
ISSN:0340-6717