OBJECTIVES: To retrospectively analyze the variation and characteristics of phenylalanine hydroxylase (PAH) gene, and to observe the long-term treatment effect and follow-up of newborns with PAH deficiency. METHODS: Clinical data, treatment and follow-up results of 198 patients with PAH deficiency diagnosed by newborn screening in Jinan from 1996 to 2021 were collected. The genetic analysis of 55 patients with PAH deficiency diagnosed by newborn screening in Jinan and 213 patients referred from the surrounding areas of Jinan were summarized. Gene variations were checked by a customized Panel gene detection method. Blood phenylalanine-concentration and physical development indicators including height and weight were regularly monitored. Intellectual development was assessed using a neuropsychological development scale for patients aged 0-6 years and academic performance, and brain injury in patients was assessed using brain magnetic resonance imaging. RESULTS: c.728G>A, c.158G>A, c.721C>T, c.1068C>A, c.611A>G variations were common in PAH gene. The genotype of c.158G>A variation is compound heterozygous variation, with mainly a mild hyperpheny-lalaninemia. 168 patients with PAH deficiency who were followed-up regularly had normal physical development without dwarfism or malnutrition. Among the 33 preschool patients who underwent mental development assessment, 2 were mentally retarded and the initial treatment age was older than 6 months. Nine patients with an average age of (17.13±2.42) years completed brain magnetic resonance imaging, one case was normal, and 8 cases were abnormal. There were patchy or patchy hyperintense foci near the bilateral lateral ventricles on T₂WI, and the intellectual development was normal. Compared with the other eight patients, the blood phenylalanine concentration of the normal child was better and stably controlled within the ideal range. CONCLUSIONS c.728G>A, c.158G>A, c.721C>T, c.1068C>A, c.611A>G variations were common in PAH gene. After standardized treatment, most patients with PAH deficiency diagnosed by screening can obtain normal growth and intellectual development in adolescence, but there are different degrees of organic lesions in the cerebral white matter.
Child ; Child, Preschool ; Adolescent ; Humans ; Infant, Newborn ; Young Adult ; Adult ; Neonatal Screening ; Follow-Up Studies ; Retrospective Studies ; Phenylketonurias/genetics* ; Phenylalanine Hydroxylase/genetics* ; Phenylalanine/therapeutic use* ; Mutation

The biogenic monoamine 5-hydroxytryptamine (5-HT) is an ancient intracellular signaling molecule widely distributed in all animals with nervous systems, and has been implicated in principal behaviors. Tryptophan hydroxylase (TRH) induces a highly specific catalytic reaction that converts L-tryptophan (tryptophan) to 5-hydroxy-L-tryptophan (5-HTP) that is subsequently used as a substrate by aromatic L-amino acid decarboxylase (DDC) to form 5-HT. Five-HT is an ancient intracellular signaling molecule that is widely distributed in the animal kingdom and has been implicated in regulating the behaviors of animals with nervous systems. However, the role of TRH in Lepidoptera is not well understood. In this study, we cloned 1 667 bp cDNAs of Bombyx mori TRH (BmTRH), which contains a 1 632 bp open reading frame (ORF). Homology analysis revealed that BmTRH shared high amino acid identity with Homo sapiens TPH and Drosophila TRH (DmTRH). The high homology (70%) of BmTRH with DmTRH suggested that BmTRH could have a function similar to DmTRH. Gene expression analysis revealed that BmTRH was mainly expressed in head and central nervous (CNS). Moreover, immunohistochemistry and Western blotting analyses showed that BmTRH was detected only in larval nervous tissues. Taken together, our results indicate that BmTRH could likely function in the regulation of neural activities in B. mori. The transcripts of B. mori decarboxylase (BmDDC) and B. mori phenylalanine hydroxylase (BmPAH) whose proteins had TRH activity, were also expressed in the CNS tissues, indicating that unlike in Drosophila, two distinct mechanisms likely regulate 5-HT synthesis in silkworm.
Amino Acid Sequence ; Animals ; Bombyx ; Cloning, Molecular ; DNA, Complementary ; Insect Proteins ; Phenylalanine Hydroxylase ; Tryptophan Hydroxylase

Consensus ; Humans ; Nutritional Requirements ; Phenylalanine ; blood ; Phenylalanine Hydroxylase ; deficiency ; Phenylketonurias ; diagnosis ; diet therapy ; genetics ; Practice Guidelines as Topic

OBJECTIVE: To explore the characteristics of PAH gene variants among 113 phenylketonuria patients from Henan Province. METHODS: The 13 exons of the PAH gene were subjected to PCR amplification and direct sequencing. Large fragment deletion and duplication of the PAH gene were detected with a multiple ligation-dependent probe amplification (MLPA) assay. RESULTS: In total 195 point variants and 3 large fragment deletions were detected among the 226 alleles, with the detection rates being 86.28% and 1.33%, respectively. Variants of p.Arg243Gln (18.14%), p.Arg111X (6.19%), p.Arg53His (5.31%), EX6-96A>G (5.31%), p.Tyr356X (4.87%) and p.Val399Val (4.42%) were relatively common. Most of the variants were located in exons 7, 11, 3 and 6. Missense variations were most common. Four novel variations were detected, which included c.1016C>A (p.Ser339Tyr), c.1000T>C (p.Cys334Arg), c.1110G>T (p.Glu370Asp), and IVS6+1G>T. CONCLUSION The PAH gene variations in Henan Province have featured extensive allelic heterogeneity and variety.
China ; Exons ; Humans ; Mutation, Missense ; Phenylalanine Hydroxylase ; genetics ; Phenylketonurias ; genetics ; Point Mutation ; Sequence Deletion

OBJECTIVETo explore the characteristics of (PAH) gene mutations among patients with phenylketonuria (PKU) from Linyi area of Shandong Province.

METHODSFor 51 children affected with PKU and their parents, the 13 exons and their flanking intronic sequences of the PAH gene were directly sequenced with Sanger method.

RESULTSPAH gene mutations were detected in all of the 102 alleles of the patients, which included 31 types of mutations. Common mutations included R243Q (17/102, 16.67%), IVS4-1G to A (9/102, 8.82%), R241C (8/102, 7.84%), R111X (8/102, 7.84%), and V399V (8/102, 7.84%). In addition, two novel mutations, D101N, 345-347del, have been detected. The 31 types of mutations included missense, nonsense, deletion, and splicing mutations, which were mainly located in exons 7 (29, 28.43%), 11 (18, 17.65%), 3 (16, 15.69%) and 12 (13, 12.75%).

CONCLUSIONMutations of the PAH gene in Linyi region mainly distributed in exons 7, 11, and 3, and the most common mutation were R243Q. Two novel mutations, D101N and 345-347del, have been detected.

Base Sequence ; Child ; Child, Preschool ; China ; Exons ; Female ; Humans ; Infant ; Male ; Molecular Sequence Data ; Mutation ; Phenylalanine Hydroxylase ; genetics ; Phenylketonurias ; enzymology ; genetics

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

This study reports a boy with psychomotor retardation and epilepsy due to maternal phenylketonuria (PKU). The boy was admitted at the age of 20 months because of psychomotor retardation and epilepsy. He had seizures from the age of 1 year. His development quotient was 43. He presented with microcephaly, normal skin and hair color. Brain MRI scan showed mild cerebral white matter demyelination, broadening bilateral lateral ventricle and foramen magnum stricture. Chromosome karyotype, urine organic acids, blood amino acids and acylcarnitines were normal. His mother had mental retardation from her childhood. She presented with learning difficulties and yellow hair. Her premarriage health examinations were normal. She married a healthy man at age of 26 years. When she visited us at 28 years old, PKU was found by markedly elevated blood phenylalanine (916.54 μmol/L vs normal range 20-120 μmol/L). On her phenylalanine hydroxylase (PAH) gene, a homozygous mutations c.611A>G (p.Y204C) was identified, which confirmed the diagnosis of PAH-deficient PKU. Her child carries a heterozygous mutation c.611A>G with normal blood phenylalanine. Her husband had no any mutation on PAH. It is concluded that family investigation is very important for the etiological diagnosis of the children with mental retardation and epilepsy. Carefully clinical and metabolic survey should be performed for the parents with mental problems to identify parental diseases-associated child brain damage, such as maternal PKU.
Adult ; Epilepsy ; etiology ; Female ; Humans ; Infant ; Intellectual Disability ; etiology ; Male ; Phenylalanine Hydroxylase ; genetics ; Phenylketonuria, Maternal ; Pregnancy

OBJECTIVETo delineate the mutation spectrum of phenylalanine hydroxylase (PAH) gene among patients affected with phenylalanine hydroxylase deficiency (PAHD) in Henan Province of China, and to explore the correlation between the genotype and the phenotype.

METHODSA total of 155 affected children were recruited. Potential mutation of the PAH gene were analyzed by direct sequencing. The genotype-phenotype correlation was analyzed by matching the expected and observed phenotypes.

RESULTSOver 72 mutations and 108 genotypes have been identified. There were 7 homozygous mutations, including 1 case with EX6-96A>G/EX6-96A>G, 1 with R241C/R241C, 1 with R413P/R413P, and 4 with R243Q/R243Q. Among these, 6 patients have presented classic PKU phenotypes, except for a R241C/R241C genotype which has led to mild PKU. In 104 patients carrying compound PAH mutations, 52 were classic, 34 were mild and 39 had mild HPA. Patients who were heterozygous for EX6-96A>G/R241C, R243Q/A434D, EX6-96A>G/R413P and EX6-96A>G/ R241C were found with both the classic PKU and mild PKU phenotypes. Common mutations associated with mild HPA have included R53H, R243Q, V399V and H107R. The common mutations associated with mild PKU included R243Q, R241C, EX6-96A>G, and IVS4-1G>A. The prevalent mutations in classic PKU were R243Q, EX6-96A>G and V399V. The consistency between prediction of the biochemical genotype and observed phenotype was 77.78%, especially in classic PKU, the consistency was up to 82.14%. Significant correlations were disclosed between pretreatment levels of phenylalanine and AV sum (r=-0.6729, P < 0.01).

CONCLUSIONThe mutation spectrum of PAH gene in Henan seems to differ from that of other regions. Independent assortment of mutant alleles may result in a complex genotype-phenotype correlation, but the genotypes of PAHD patients have correlated with the phenotype.

Female ; Genotype ; Humans ; Male ; Mutation ; Phenotype ; Phenylalanine Hydroxylase ; genetics ; Phenylketonurias ; genetics

In proteins of thermophilic bacteria, Gly is tend to be replaced by Ala and Lys is tend to be replaced by Arg to adapt the high temperature. In order to improve the thermal stability of phenylalanine hydroxylase (PAH) from Chromobacterium violaceum, all the Gly on PAH were mutated to Ala and Lys to Arg. Positive mutant enzymes with improved thermal stability were selected, followed by combined mutation and characterization. The results revealed that half-lives of K94R and G221A mutants at 50 °C were 26.2 min and 16.8 min, which were increased by 1.9-times and 0.9-times than the parent enzyme (9.0 min). The residual activity of K94R/G221A mutant was improved to 65.6% after keeping at 50 °C for 1 h, which was 6.6 time higher than the parent enzyme (8.6%). Circular dichroism (CD) spectroscopy revealed that Tm values of the parent enzyme, K94R, G221A and K94R/G221A were 51.5 ℃, 53.8 ℃, 53.1 ℃ and 54.8 ℃, respectively. According to the protein structure simulation, the two mutations were located on flexible loop. In the K94R mutant, the mutated Arg94 on the surface of the enzyme formed an extra hydrogen bond with Ile95, which stabilized the located loop. In the G221A mutant, the mutated Ala221 formed hydrophobic interaction with Leu281, which could stabilize both the loop and flexible area of the C-terminus of G221A. The results not only provided a reference for protein modification on thermal stability, but also laid the foundation for application of phenylalanine hydroxylase in the field of functional foods.
Bacterial Proteins ; biosynthesis ; genetics ; Chromobacterium ; enzymology ; Enzyme Stability ; Hot Temperature ; Kinetics ; Mutagenesis, Site-Directed ; Mutation ; Phenylalanine Hydroxylase ; biosynthesis ; genetics ; Protein Engineering

OBJECTIVETo study the characteristics of phenylalanine hydroxylase gene (PAH) mutations in patients with PAH deficiency in Fujian population.

METHODSPeripheral blood samples of 36 patients and their parents with classical type phenylketouria (PKU) were collected. Genomic DNA was extracted. Following PCR amplification, DNA sequencing was carried out to identify the origins of mutations.

RESULTSTwenty types mutations were identified in 63 of the 72 alleles. The most common mutations were R241C, R408Q and Ex6-96A>G, which respectively accounted for 15.9%, 12.7% and 11.1% of all mutant alleles. The c.189_190dupTGAC mutation was first reported. R241C was associated with 28% of mild hyperphenylalaninemia and R408Q is associated with 25% of classical PKU.

CONCLUSIONThere is a specific spectrum of PAH gene mutation in Fujian region. R241C, R408Q and Ex6-96A>G are the most common mutations.

Adolescent ; Alleles ; Asian Continental Ancestry Group ; genetics ; Base Sequence ; Child ; Child, Preschool ; China ; Female ; Genotype ; Humans ; Male ; Molecular Sequence Data ; Mutation ; Phenylalanine Hydroxylase ; genetics ; Phenylketonurias ; enzymology ; genetics