Phenylalanine hydroxylase (PAH) is a member of aromatic amino acid hydroxylase (AAAHs) family, and catalyze phenylalanine (Phe) into tyrosine (Tyr). Using immunological and RT-PCR methods to prove the existence of phenylalanine hydroxylase (PAH) gene in the brain of Neanthes japonica in protein and nucleic acid level. Using Western blotting to detect the pah immunogenicity of Neanthes japonica. Making paraffin sections and using immunohistochemical technique to identify the presence and distribution of the phenylalanine hydroxylase gene in the brain of Neanthes japonica. Clone pah gene from the brain of Neanthes japonica by RT-PCR, constructing plasmid and transferring into E. coli to amplification, picking a single homogeneous colony, double digesting then making sequence and comparing homology. Western blotting results showed that the expression of the protein is present in Neanthes japonica brain, immunohistochemistry technique results showed that phenylalanine hydroxylase mainly expressed in abdominal of forebrain, dorsal and sides of midbrain. RT-PCR technique results showed that the phenylalanine hydroxylase exist in the brain of Neanthes japonica and has a high homology with others animals. PAH is present in the lower organisms Neanthes japonica, in protein and nucleic acid level. Which provide the foundation for further study the evolution of aromatic amino acid hydroxylase genes in invertebrate.
Animals ; Blotting, Western ; Brain ; enzymology ; Escherichia coli ; metabolism ; Phenylalanine Hydroxylase ; genetics ; metabolism ; Polychaeta ; enzymology ; genetics

OBJECTIVETo determine the gene mutation spectrum of patients with 6-pyruvoyltetrahydrobiopterin synthesis deficiency (PTPSD) in Mainland China.

METHODSThe 6-pyruvoyltetrahydrobiopterin synthesis gene lz(PTS)lz was analyzed in 55 PTPSD patients by using PCR-restriction fragment length polymorphism (PCR-RFLP) and direct DNA sequencing. The relationship between the genotype and phenotype was analyzed.

RESULTSEighteen mutations were identified and the detection rate of gene mutation was 95.28%. Four hot-spot mutations, namely P87S (40.57%), N52S(13.21%), D96N(12.26%) and IVS1nt-291A to G(10.38%) were found in this study, and the first three were associated with severe phenotype. The P87L was reported firstly in Chinese patients, and the Q13X, M80T, IVS4nt-2A to G, L93M and K131N were novel mutations.

CONCLUSIONThe P87S, N52S, D96N and IVS1nt-291A to G mutations are the hot-spots mutations of the PTS gene in Chinese PTPSD patients. Using PCR-RFLP technique to screen the mutations in the PTS gene can increase the efficiency of gene diagnosis.

Adult ; Asian Continental Ancestry Group ; genetics ; Base Sequence ; China ; DNA Mutational Analysis ; Female ; Genotype ; Humans ; Male ; Metabolic Diseases ; genetics ; Mutation ; Pedigree ; Phenylalanine Hydroxylase ; genetics ; metabolism ; Polymerase Chain Reaction ; Polymorphism, Restriction Fragment Length ; Pregnancy ; Pterins ; metabolism ; Steroid 21-Hydroxylase ; genetics ; metabolism

A consistent finding of many studies describing the spectrum of mutant phenylalanine hydroxylase (PAH) alleles underlying hyperphenylalaninemia is the impossibility of achieving a 100% mutation ascertainment rate using conventional gene-scanning methods. These methods include denaturing gradient gel electrophoresis (DGGE), denaturing high performance liquid chromatography (DHPLC), and direct sequencing. In recent years, it has been shown that a significant proportion of undetermined alleles consist of large deletions overlapping one or more exons. These deletions have been difficult to detect in compound heterozygotes using gene-scanning methods due to a masking effect of the non-deleted allele. To date, no systematic search has been carried out for such exon deletions in Italian patients with phenylketonuria or mild hyperphenylalaninemia. We used multiplex ligation- dependent probe amplification (MLPA), comparative multiplex dosage analysis (CMDA), and real-time PCR to search for both large deletions and duplications of the phenylalanine hydroxylase gene in Italian hyperphenylalaninemia patients. Four deletions removing different phenylalanine hydroxylase (PAH) gene exons were identified in 12 patients. Two of these deletions involving exons 4-5-6-7-8 (systematic name c.353-?_912 + ?del) and exon 6 (systematic name c.510-?_706 + ?del) have not been reported previously. In this study, we show that exon deletion of the PAH gene accounts for 1.7% of all mutant PAH alleles in Italian hyperphenylalaninemics.
DNA Mutational Analysis/*methods ; Disease Progression ; Exons/genetics ; Gene Frequency ; Humans ; Italy ; Phenylalanine Hydroxylase/*genetics/metabolism ; Phenylketonurias/epidemiology/*genetics/physiopathology ; Reverse Transcriptase Polymerase Chain Reaction ; Sequence Deletion/genetics

OBJECTIVETo investigate the correlation between genotypes and biochemical phenotypes of phenylalanine hydroxylase (PAH) in patients with phenylketonuria (PKU).

METHODSThirteen exons and flanking introns of PAH gene in 102 patients with high blood phenylalanine levels (Phe > 120 umol/L) at initial diagnosis were amplified with polymerase chain reaction and analyzed with single strand conformation polymorphism (SSCP), denaturing high performance liquid chromatography (DHPLC) and DNA sequencing. Correlation between genotypes and biochemical phenotypes was analyzed.

RESULTSBiochemical assaying has indicated that 69 patients had classical PKU (Phe> 1200 umol/L), 31 were moderate (Phe 600-1200 umol/L), and 2 were mild (Phe 400-600 umol/L). More than 41 mutations and 75 genotypes have been identified. There were 9 (8.8%) homozygous mutations, which included 3 cases with R111X/R111X, 1 case with IVS4-1G>A/IVS4-1G>A, 3 cases with R243Q/R243Q and 2 cases with V399V/V399V. Among these 8 belonged to classic PKU phenotypes, except for a R243Q/R243Q genotype which has led to a moderate phenotype. In 91 patients carrying compound PAH mutations, 61 were classic, 29 were moderate, and 1 was mild. Patients who were heterozygous for R111X/R243Q and EX6-96A>G(Y204C)/R243Q were found with both classic and moderate PKU phenotypes. Certain individuals who have carried 2 null mutant alleles such as R111X/V399V, EX6-96A>G/Y356X and EX6-96A>G/V399V only showed a moderate phenotype. Individuals with R111X/A165D and R176X/A165D genotypes, on the other hand, respectively presented moderate and classic PKU phenotypes.

CONCLUSIONNinety percent of our patients are compound heterozygotes. Independent assortment of mutant alleles has resulted in a complex genotype-phenotype correlation. Although in most cases a correlation may be found, caution should still be taken upon genetic counseling. The phenomena where similar or even identical genotype may give rise to different biochemical phenotypes have implied that other factors may also influence the phenylalanine metabolism.

Adolescent ; Alleles ; Child ; Child, Preschool ; Exons ; Female ; Gene Frequency ; Genetic Association Studies ; Genotype ; Humans ; Infant ; Infant, Newborn ; Introns ; Male ; Mutation ; Phenotype ; Phenylalanine Hydroxylase ; genetics ; metabolism ; Phenylketonurias ; genetics ; metabolism

OBJECTIVETo study the incidence of various enzyme deficiency in tetrahydrobiopterin (BH4) metabolism and the related gene mutation among the patients with motor disturbance and mental retardation.

METHODSOne hundred patients with unknown motor disturbance and mental retardation were referred to this study. All patients were performed by phenylalanine (Phe) and BH4 loading test, urinary pterin analysis and dihydropteridine reductase (DHPR) activity. Some patients received the dopa treatment for diagnosis of dopa-responsive dystonia (DRD). The analysis of GTP cyclohydrolase 1 gene (GCH1) mutation for DRD patients and the analysis of 6-pyruvoyl tetrahydropterin synthase (PTS) gene mutations for PTS deficient patients were done under the consent from their parents.

RESULTSSeventy of 100 patients had normal basic blood Phe levels, six (6%) patients were diagnosed as DRD. Thirty patients had hyperphenylalaninemia (HPA), eight (8%) were diagnosed as PTS deficiency and 22(22%) were diagnosed as phenylalanine hydroxylase (PAH) deficiency. All patients had normal DHPR activity. The mutation IVS5+3insT of GCH1 was found in 2 patients with DRD. Seven kinds of PTS mutations were found in 8 patients with PTS deficiency, and 75% of the mutations were 259C-->T,286G-->A and 155A-->G.

CONCLUSIONSome patients with unknown motor disturbance and mental retardation may suffer from BH4 metabolism related diseases. Theses patients are necessary to be screened for such kind of diseases in order to confirm the diagnosis.

Adolescent ; Biopterin ; analogs & derivatives ; metabolism ; Child ; Child, Preschool ; Dihydropteridine Reductase ; genetics ; metabolism ; Dystonia ; genetics ; metabolism ; Female ; GTP Cyclohydrolase ; genetics ; metabolism ; Humans ; Infant ; Intellectual Disability ; genetics ; metabolism ; Male ; Mutation ; Phenylalanine Hydroxylase ; genetics ; metabolism ; Phosphorus-Oxygen Lyases ; genetics ; metabolism

Phenylketonuria is an autosomal recessive disorder caused by a deficiency of phenylalanine hydroxylase. Transthyretin has been implicated as an indicator of nutritional status in phenylketonuria patients. In this study, we report that phenylalanine and its metabolite, phenylpyruvic acid, affect MAPK, changing transthyretin expression in a cell- and tissue-specific manner. Treatment of HepG2 cells with phenylalanine or phenylpyruvic acid decreased transcription of the TTR gene and decreased the transcriptional activity of the TTR promoter site, which was partly mediated through HNF4alpha. Decreased levels of p38 MAPK were detected in the liver of phenylketonuria-affected mice compared with wild-type mice. In contrast, treatment with phenylalanine increased transthyretin expression and induced ERK1/2 activation in PC-12 cells; ERK1/2 activation was also elevated in the brainstem of phenylketonuria-affected mice. These findings may explain between-tissue differences in gene expression, including Ttr gene expression, in the phenylketonuria mouse model.
Animals ; Brain Stem/metabolism/pathology ; Disease Models, Animal ; Gene Expression Regulation ; Hep G2 Cells ; Hepatocyte Nuclear Factor 4/metabolism ; Humans ; Liver/*metabolism/pathology ; Mice ; Mice, Mutant Strains ; Mitogen-Activated Protein Kinase 3/genetics/*metabolism ; Organ Specificity ; Phenylalanine/metabolism ; Phenylalanine Hydroxylase/deficiency ; Phenylketonurias/*genetics/metabolism/pathology/physiopathology ; Phenylpyruvic Acids/metabolism ; Prealbumin/*biosynthesis/genetics ; p38 Mitogen-Activated Protein Kinases/genetics/*metabolism

OBJECTIVETo understand the pathogenic effect and the correlation between the genotype and phenotype of the 4 novel missense mutations (G247S, E280G, P362T and A434D) of phenylalanine hydroxylase gene (PAH).

METHODS(1) The enzyme activity of the 4 mutants was assessed by using transient protein expression in mammalian cells. (2) The PAH amino acid sequences among different animal species were alignmented. (3) The effects of the 4 missense mutations on the protein structure were analyzed. (4) The clinical phenotype of the patients with PKU were analyzed, according to their blood Phe levels prior to treatment and the Phe tolerance.

RESULTS(1) The residual enzyme activity expressed in vitro of G247S, E280G, P362T and A434D were 3.1%, 0.4%, 8.2% and 21.7% of the wild-type PAH respectively; (2)Gly247, Glu280 and Pro362 were among the highly conserved amino acids, while Ala434 was only moderately conserved; (3) As revealed by 3D structural analysis, G247S and E280G, being located at the active center of the enzyme, interfered with the binding of PAH to BH4 and ferrousion respectively, while P362T and A434D affected the formation and stability of the dimer and the tetramer of PAH; (4) As shown by clinical phenotypic analysis, classical PKU were observed in patients carrying G247S and E280G, moderate PKU were observed in patients carrying A434D, whereas both classical and moderate PKU were observed in patients carrying P362T.

CONCLUSION(1) The E280G, G247S, P362T and A434D are all disease-causing mutations, with those located at the center of the enzyme displaying the most marked pathogenic effect; (2)The results of the structural analysis of the 3D molecule are consistent with the activity assessment of the enzyme expressed in vitro; (3) The consistency is observed between the genotype, the enzymatic activity expressed in vitro and the clinical phenotype.

Amino Acid Sequence ; Animals ; Child ; Child, Preschool ; Female ; Gene Expression ; Genotype ; Humans ; Infant ; Infant, Newborn ; Male ; Models, Molecular ; Molecular Sequence Data ; Mutant Proteins ; chemistry ; genetics ; metabolism ; Mutation, Missense ; Phenotype ; Phenylalanine Hydroxylase ; chemistry ; genetics ; metabolism ; Phenylketonurias ; enzymology ; genetics ; Protein Conformation ; Sequence Alignment ; Structure-Activity Relationship