Molecular basis of phenotypic heterogeneity in phenylketonuria. 1991

Y Okano, and R C Eisensmith, and F Güttler, and U Lichter-Konecki, and D S Konecki, and F K Trefz, and M Dasovich, and T Wang, and K Henriksen, and H Lou
Howard Hughes Medical Institute, Department of Cell Biology, Baylor College of Medicine, Houston, TX 77030.

BACKGROUND Phenylketonuria is a metabolic disorder that results from a deficiency of the hepatic enzyme phenylalanine hydroxylase. Its clinical phenotype varies widely, and to date more than 10 mutations in the phenylalanine hydroxylase gene have been identified in persons with the disorder. We attempted to relate the clinical phenotype of patients to their genotype. METHODS We studied 258 patients with phenylketonuria from Denmark and Germany for the presence of eight mutations previously found in patients from these countries. The in vitro activity of the enzymes associated with these mutations was determined by expression analysis in heterologous mammalian cells. The level of activity was then used to predict the in vivo level of phenylalanine hydroxylase activity in patients with various combinations of mutant phenylalanine hydroxylase alleles. RESULTS The eight mutations involved 64 percent of all mutant phenylalanine hydroxylase alleles in the patients. Expression analysis showed that these mutant enzymes produced from 0 to 50 percent of normal enzyme activity. The predicted level of phenylalanine hydroxylase activity correlated strongly with the pretreatment serum level of phenylalanine (r = 0.91, P less than 0.001 in the Danish patients and r = 0.74, P less than 0.001 in the German patients), phenylalanine tolerance in the Danish patients (r = 0.84, P less than 0.001), and the serum phenylalanine level measured after standardized oral protein loading in the German patients (r = 0.84, P less than 0.001). CONCLUSIONS Our results strongly support the hypothesis that there is a molecular basis for phenotypic heterogeneity in phenylketonuria. The establishment of genotype will therefore aid in the prediction of biochemical and clinical phenotypes in patients with this disease.

UI MeSH Term Description Entries
D009154 Mutation Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations. Mutations
D009693 Nucleic Acid Hybridization Widely used technique which exploits the ability of complementary sequences in single-stranded DNAs or RNAs to pair with each other to form a double helix. Hybridization can take place between two complimentary DNA sequences, between a single-stranded DNA and a complementary RNA, or between two RNA sequences. The technique is used to detect and isolate specific sequences, measure homology, or define other characteristics of one or both strands. (Kendrew, Encyclopedia of Molecular Biology, 1994, p503) Genomic Hybridization,Acid Hybridization, Nucleic,Acid Hybridizations, Nucleic,Genomic Hybridizations,Hybridization, Genomic,Hybridization, Nucleic Acid,Hybridizations, Genomic,Hybridizations, Nucleic Acid,Nucleic Acid Hybridizations
D010641 Phenotype The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment. Phenotypes
D010649 Phenylalanine An essential aromatic amino acid that is a precursor of MELANIN; DOPAMINE; noradrenalin (NOREPINEPHRINE), and THYROXINE. Endorphenyl,L-Phenylalanine,Phenylalanine, L-Isomer,L-Isomer Phenylalanine,Phenylalanine, L Isomer
D010651 Phenylalanine Hydroxylase An enzyme of the oxidoreductase class that catalyzes the formation of L-TYROSINE, dihydrobiopterin, and water from L-PHENYLALANINE, tetrahydrobiopterin, and oxygen. Deficiency of this enzyme may cause PHENYLKETONURIAS and PHENYLKETONURIA, MATERNAL. EC 1.14.16.1. Phenylalanine 4-Hydroxylase,Phenylalanine 4-Monooxygenase,4-Hydroxylase, Phenylalanine,4-Monooxygenase, Phenylalanine,Hydroxylase, Phenylalanine,Phenylalanine 4 Hydroxylase,Phenylalanine 4 Monooxygenase
D010661 Phenylketonurias A group of autosomal recessive disorders marked by a deficiency of the hepatic enzyme PHENYLALANINE HYDROXYLASE or less frequently by reduced activity of DIHYDROPTERIDINE REDUCTASE (i.e., atypical phenylketonuria). Classical phenylketonuria is caused by a severe deficiency of phenylalanine hydroxylase and presents in infancy with developmental delay; SEIZURES; skin HYPOPIGMENTATION; ECZEMA; and demyelination in the central nervous system. (From Adams et al., Principles of Neurology, 6th ed, p952). Biopterin Deficiency,Dihydropteridine Reductase Deficiency Disease,Hyperphenylalaninemia, Non-Phenylketonuric,Phenylalanine Hydroxylase Deficiency Disease,BH4 Deficiency,DHPR Deficiency,Deficiency Disease, Dihydropteridine Reductase,Deficiency Disease, Phenylalanine Hydroxylase,Deficiency Disease, Phenylalanine Hydroxylase, Severe,Dihydropteridine Reductase Deficiency,Folling Disease,Folling's Disease,HPABH4C,Hyperphenylalaninaemia,Hyperphenylalaninemia Caused by a Defect in Biopterin Metabolism,Hyperphenylalaninemia, BH4-Deficient, C,Hyperphenylalaninemia, Tetrahydrobiopterin-Deficient, Due To DHPR Deficiency,Non-Phenylketonuric Hyperphenylalaninemia,Oligophrenia Phenylpyruvica,PAH Deficiency,PKU, Atypical,Phenylalanine Hydroxylase Deficiency,Phenylalanine Hydroxylase Deficiency Disease, Severe,Phenylketonuria,Phenylketonuria I,Phenylketonuria II,Phenylketonuria Type 2,Phenylketonuria, Atypical,Phenylketonuria, Classical,QDPR Deficiency,Quinoid Dihydropteridine Reductase Deficiency,Tetrahydrobiopterin Deficiency,Atypical PKU,Atypical Phenylketonuria,Biopterin Deficiencies,Classical Phenylketonuria,Deficiency, BH4,Deficiency, Biopterin,Deficiency, DHPR,Deficiency, Dihydropteridine Reductase,Deficiency, PAH,Deficiency, Phenylalanine Hydroxylase,Deficiency, QDPR,Deficiency, Tetrahydrobiopterin,Disease, Folling,Disease, Folling's,Hyperphenylalaninemia, Non Phenylketonuric,Non Phenylketonuric Hyperphenylalaninemia,Non-Phenylketonuric Hyperphenylalaninemias
D003718 Denmark A country in northern Europe, bordering the Baltic Sea and the North Sea. The capital is Copenhagen. Faeroe Islands,Faroe Islands
D005858 Germany A country in central Europe, bordering the Baltic Sea and the North Sea, between the Netherlands and Poland, south of Denmark. The capital is Berlin.
D006801 Humans Members of the species Homo sapiens. Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000483 Alleles Variant forms of the same gene, occupying the same locus on homologous CHROMOSOMES, and governing the variants in production of the same gene product. Allelomorphs,Allele,Allelomorph

Related Publications

Y Okano, and R C Eisensmith, and F Güttler, and U Lichter-Konecki, and D S Konecki, and F K Trefz, and M Dasovich, and T Wang, and K Henriksen, and H Lou
October 1980, Die Naturwissenschaften,
Y Okano, and R C Eisensmith, and F Güttler, and U Lichter-Konecki, and D S Konecki, and F K Trefz, and M Dasovich, and T Wang, and K Henriksen, and H Lou
January 1990, Postepy biochemii,
Y Okano, and R C Eisensmith, and F Güttler, and U Lichter-Konecki, and D S Konecki, and F K Trefz, and M Dasovich, and T Wang, and K Henriksen, and H Lou
August 1996, Annals of neurology,
Y Okano, and R C Eisensmith, and F Güttler, and U Lichter-Konecki, and D S Konecki, and F K Trefz, and M Dasovich, and T Wang, and K Henriksen, and H Lou
September 2001, Human mutation,
Y Okano, and R C Eisensmith, and F Güttler, and U Lichter-Konecki, and D S Konecki, and F K Trefz, and M Dasovich, and T Wang, and K Henriksen, and H Lou
April 2003, Human mutation,
Y Okano, and R C Eisensmith, and F Güttler, and U Lichter-Konecki, and D S Konecki, and F K Trefz, and M Dasovich, and T Wang, and K Henriksen, and H Lou
April 2003, Human mutation,
Y Okano, and R C Eisensmith, and F Güttler, and U Lichter-Konecki, and D S Konecki, and F K Trefz, and M Dasovich, and T Wang, and K Henriksen, and H Lou
January 2004, Journal of human genetics,
Y Okano, and R C Eisensmith, and F Güttler, and U Lichter-Konecki, and D S Konecki, and F K Trefz, and M Dasovich, and T Wang, and K Henriksen, and H Lou
January 1989, Biochemistry,
Y Okano, and R C Eisensmith, and F Güttler, and U Lichter-Konecki, and D S Konecki, and F K Trefz, and M Dasovich, and T Wang, and K Henriksen, and H Lou
December 2012, Nature reviews. Cancer,
Y Okano, and R C Eisensmith, and F Güttler, and U Lichter-Konecki, and D S Konecki, and F K Trefz, and M Dasovich, and T Wang, and K Henriksen, and H Lou
February 2010, BMC medical genetics,
Copied contents to your clipboard!