OBJECTIVETo investigate the type and frequency of mutations in exon 7 of phenylalanine hydroxylase (PAH) gene among children with phenylketonuria (PKU) in Ningxia, China and to provide a basis for the genetic diagnosis and prenatal diagnosis of PKU in this region.

METHODSDirect sequencing of PCR product was performed to analyze the sequences of exon 7 and its flanking introns of 146 PAH alleles in 73 children with typical PKU (39 cases of Hui nationality and 34 cases of Han nationality) in Ningxia.

RESULTSSix mutations were detected, including R243Q (14.4%), R241C (6.8%), IVS7+2T→A (2.7%), L255S (0.7%), G247V (0.7%), and G247R (0.7%). The overall frequency of mutations (missense mutation and splice site mutation) in exon 7 was 26.0% (38/146). The detection rate of R241C mutation was significantly higher in children of Hui nationality than in children of Han nationality(10% vs 3%; P<0.05).

CONCLUSIONSIn Ningxia, R243Q mutation in exon 7 of PAH gene is most common in children with PKU, followed by R241C. The frequency of R241C mutation in exon 7 of PAH gene varies between children with PKU of Hui and Han nationality.

China ; ethnology ; Exons ; Humans ; Mutation ; Phenylalanine Hydroxylase ; genetics ; Phenylketonurias ; genetics

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

OBJECTIVETo study the mutation characteristics of the phenylalanine hydroxylase (PAH) gene in children with phenylketonuria (PKU) from the Qinghai area of China, in order to provide basic information for genetic counseling and prenatal diagnosis.

METHODSMutations of the PAH gene were detected in the promoter and exons 1-13 and their flanking intronic sequences of PAH gene by PCR and DNA sequencing in 49 children with PKU and their parents from the Qinghai area of China.

RESULTSA total of 30 different mutations were detected in 80 out of 98 mutant alleles (82%), including 19 missense (63%), 5 nonsense (17%), 3 splice-site (10%) and 3 deletions (10%). Most mutations were detected in exons 3, 6, 7, 11 and intron 4 of PAH gene. The most frequent mutations were p.R243Q (19%), IVS4-1G>A (9%), p.Y356X (7%) and p.EX6-96A>G(5%). Two novel mutations p.N93fsX5 (c.279-282delCATC) and p.G171E (c.512G>A) were found. p.H64fsX9(c.190delC) was documented for the second time in Chinese PAH gene. The mutation spectrum of the gene PAH in the Qinghai population was similar to that in other populations in North China while significantly different from that in the populations from some provinces in southern China, Japan and Europe.

CONCLUSIONSThe mutations of PAH gene in the Qinghai area of China demonstrate a unique diversity, complexity and specificity.

Child ; Child, Preschool ; China ; Female ; Humans ; Infant ; Male ; Mutation ; Phenylalanine Hydroxylase ; genetics ; Phenylketonurias ; genetics

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

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

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

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

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

OBJECTIVETo explore new mutation in phenylalanine hydroxylase (PAH) gene.

METHODSThe PAH genes from 40 phenylketonuria (PKU) patients and 30 normal controls were screened by PCR-single strand conformation polymorphism (SSCP) and further sequencing.

RESULTSEleven mutations and 3 polymorphisms in PAH gene were found. No abnormalities in the PAH gene from 30 controls were detected.

CONCLUSIONM276K, M276R, 280insT, IVS10nt+32T-->A, IVS4nt+47C-->T were demonstrated as novel mutations in comparison with the PAH mutation database. One mission mutation (H290R) was first documented in Chinese PKU gene.

DNA Mutational Analysis ; Female ; Humans ; Infant ; Male ; Mutation ; Phenylalanine Hydroxylase ; genetics ; Phenylketonurias ; genetics ; Polymerase Chain Reaction ; Polymorphism, Single-Stranded Conformational

OBJECTIVETo obtain the mutation spectrum of exon 12 of the phenylalanine hydroxylase(PAH) gene.

METHODSThe samples from 127 patients with phenylketonuria(PKU) were studied by polymerase chain reaction(PCR)-single strand conformation polymorphism(SSCP) PCR-denaturing gradient gel electrophoresis(DGGE) and direct DNA sequencing.

RESULTSFour heterozygous mutations including R413P S411X R408W R408Q in 10 of 127 patients were identified by DNA sequencing. The frequencies of R413P S411X R408W R408Q mutation were 2.76%, 0.39%, 0.39% and 0.39%, respectively. The S411X mutation in Chinese was first reported. Only 2 cases with R413P mutation were detected by SSCP. DGGE analysis showed that 10 cases displayed 3 kinds of abnormal electrophoretic bands. There were no obvious differences in the frequency of R413P mutation between northern and southern Chinese with PKU, and between classical PKU and hyperphenylalaninemia.

CONCLUSIONDGGE is more sensitive than SSCP in screening the mutations of exon 12 of the PAH gene. DGGE combined with DNA sequencing can be used to define all the mutations of exon 12 of the PAH gene. These results indicate the similarity in the frequency of R413P mutation between northern and southern patients.

Electrophoresis, Polyacrylamide Gel ; Exons ; Humans ; Mutation ; Phenylalanine Hydroxylase ; genetics ; Phenylketonurias ; genetics ; Polymorphism, Single-Stranded Conformational ; Sequence Analysis, DNA