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Tetrahydrobiopterin sensitivity in German patients with mild phenylalanine hydroxylase deficiency
Author(s) -
Lindner M.,
Steinfeld R.,
Burgard P.,
Schulze A.,
Mayatepek E.,
Zschocke J.
Publication year - 2003
Publication title -
human mutation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 162
eISSN - 1098-1004
pISSN - 1059-7794
DOI - 10.1002/humu.9117
Subject(s) - tetrahydrobiopterin , biology , phenylalanine hydroxylase , phenylalanine , german , endocrinology , medicine , enzyme , biochemistry , cofactor , amino acid , history , archaeology
We report the results of tetrahydrobiopterin (BH 4 ) loading tests in 10 German patients with mild phenylketonuria. A significant decline of phenylalanine values after application of BH 4 was observed in all but one patients. Molecular genetic analyses revealed a range of different PAH gene mutations. Re‐testing of one patient previously reported as non‐responsive to BH 4 loading showed a moderate response with a higher dose of BH 4 . Nevertheless, there appear to be kinetic differences in phenylalanine hydroxylation in patients with the same genotype. Non‐responsiveness to 20 mg/kg BH 4 was observed only in a single patient who was compound heterozygous for the novel mutation R176P (c.527G>C) and the common null‐mutation P281L. In summary, our data are in line with recent reports indicating that BH 4 sensitivity is a normal feature of most mild forms of PAH deficiency but may be influenced by other factors. © 2003 Wiley‐Liss, Inc.