OBJECTIVE: To explore the spectrum of genetic variants and phenotypes of Phenylalanine hydroxylase deficiency (PAHD) in Lianyungang area and the correlation between genotype and phenotypes among the patients. METHODS: Eighty children with Hyperphenylalaninemia (HPA) diagnosed at the Lianyungang Branch of Jiangsu Provincial Newborn Screening Center between January 2015 and December 2022 were enrolled. Peripheral blood samples were collected for genetic analysis using next generation sequencing (NGS), Sanger sequencing, and multiplex ligation-dependent probe amplification (MLPA) to identify the variants of PAH gene. Clinical and phenotypic data were concurrently analyzed to investigate the correlation between the types of PAH gene variant and phenotypes. This study was approved by the Medical Ethics Committee of Lianyungang Maternal and Child Health Care Hospital (Ethics No.: XM2022041). RESULTS: PAH gene variants were identified in 93.75% (75/80) of the children, classified as PAHD cases, while 6.25% (5/80) harbored PTS gene variants. Of the 150 PAH alleles from 75 PAHD children, a total of 152 variants (55 distinct types) were detected, with a detection rate of 100%. 80.26% (122/152) of the variants were located in exons, with the main types being missense variants (67.11%, 102/152). 53.29% (81/152) of coding sequence variants have occurred in the PAH gene's catalytic center region, while 19.74% (30/152) of the variants involved non-coding sequences. The phenotypes of the 75 PAHD children were evenly distributed. The re-screened Phe concentrations and Phe/Tyr ratios of classic-phenylketonuria (CPKU) and mild-phenylketonuria (MPKU) patients were markedly higher than initial screening values (P < 0.001, P < 0.001; P = 0.004, P = 0.016). The genotypes of the PAHD patients mostly occurred as compound heterozygotes, and different mutation positions and variant types have significantly affected the phenotypes (P = 0.042, P = 0.045). APV/GPV genotype-phenotype analysis of 61 patients showed high consistency between predicted and actual phenotypes (κ = 0.755, P < 0.001). CONCLUSION PAH gene variants were detected in most HPA children from Lianyungang area. The location and type of PAH gene variants has correlated with the severity of the phenotype, and the non-coding sequence variants and non-missense variants may aggravate the phenotype, and the APV/GPV model has predicted the phenotype with high consistency with the actual phenotype.
Humans ; Phenylalanine Hydroxylase/genetics* ; Female ; Phenylketonurias/enzymology* ; Male ; Phenotype ; Genotype ; Child ; Infant ; Infant, Newborn ; Child, Preschool ; China ; Mutation ; Alleles

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

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

OBJECTIVETo investigate the mutations of phenylalanine hydroxylase (PAH) gene in 20 phenylketonuria (PKU) patients from Yunnan.

METHODSThe 13 exons and the splicing regions of 12 introns of the PAH gene were sequenced to detect mutations in 20 unrelated PKU patients.

RESULTSPAH gene sequencing has revealed 15 types of mutations, in which the most frequently mutation was p.R243Q (30.0%), followed by p.Y356X(10.0%), p.R111X (7.5%), IVS4+2T>A (7.5%) and p.V399V (7.5%). Exons 7, 11, 3 and introns 4, 11 were most frequently involved. Six novel mutations, including c.59A>C, c.60G>C, c.690_691insG, c.1119_1120insT, c.441+2T>A, c.842+4A>T and c.1200+1T>G were detected.

CONCLUSIONPAH gene mutations identified in Yunnan are more similar to those of northern China, with R243R being the most common, though there are still certain characteristics for the type and frequency of mutations.

Adolescent ; Adult ; Asian Continental Ancestry Group ; genetics ; Base Sequence ; Child ; China ; Female ; Humans ; Male ; Molecular Sequence Data ; Mutation ; Phenylalanine Hydroxylase ; genetics ; Phenylketonurias ; enzymology ; genetics ; Young Adult

OBJECTIVETo investigate the feature of phenylalanine hydroxylase (PAH) gene mutations and provide guidance for genetic and prenatal diagnosis of patients with phenylketonuria from Shaanxi.

METHODSFor 55 patients whose blood Phe concentration was over 2.0 mg/dL, potential mutations in 13 exons and flanking sequences of the PAH gene were detected by PCR and DNA sequencing.

RESULTSA total of 98 mutations were detected in 110 PAH alleles, with the detection rate being 89.10%. Nine mutations have been identified in exon 7, which accounted for 33.67% of all. Exon 12 (14.29%) and exon 3 (12.24%) have followed. Thirty eight mutations, locating in exon2-exon12 and the flanking sequence, were detected in the 55 PKU patients. p.R243Q (24.49%) was the commonest mutation, whilstp.A47E, p.I65S and p.A259T were first discovered in China. After querying international databases including PAHdb and HGMD, the p.C334X was verified as the novel PAH gene mutation.

CONCLUSIONThe mutation spectrum of the PAH gene in Shaanxi has been identified. And a novel mutation has been identified. This may facilitate the diagnosis of PKU in the future.

Alleles ; Base Sequence ; Child ; Child, Preschool ; China ; Female ; Humans ; Infant ; Infant, Newborn ; Male ; Mutation ; Phenylalanine Hydroxylase ; blood ; genetics ; Phenylketonurias ; enzymology ; genetics

OBJECTIVETo determine the type and frequency of phenylalanine hydroxylase gene (PAH) mutations in ethnic Hui patients from Ningxia with phenylketonuria (PKU).

METHODSFor 35 PKU children patients and 50 healthy individuals, all exons and promoters of the PAH gene were analyzed with PCR and direct sequencing.

RESULTSTwenty mutations, including 8 missense mutations (40%), 5 nonsense mutations (25%), 4 splice site mutations (20%) and 3 deletion mutants (15%) were discovered. The overall detection rate was 68.57% (48/70). Common mutations have included R243Q (12.86%), R241C (11.43%), EX6-96A to G (5.71%), Y356X (5.71%), R413P(4.29%) and Q232X(4.29%), whilst rarer ones have included S16fsX10 (2.86%), R111X (2.86%) and L430P (2.86%). Among these, S16fsX10, L430P, D222G and IVS11+ 1G to A have not been reported previously. Y414X and S303fsX38 have not been reported in Hui ethnic group. No mutation was detected in the 50 normal controls.

CONCLUSIONThe types and distribution of PAH gene mutations in ethnic Hui from Ningxia have been different from other areas of China. The mutations also showed a rich diversity.

Adolescent ; Asian Continental Ancestry Group ; genetics ; Child ; Child, Preschool ; Female ; Humans ; Infant ; Infant, Newborn ; Male ; Mutation ; Phenylalanine Hydroxylase ; genetics ; Phenylketonurias ; enzymology ; genetics

OBJECTIVETo characterize the mutation spectrum of phenylalanine hydroxylase (PAH) gene and perform prenatal diagnosis for families with classical phenylketonuria.

METHODSBy stratified sequencing, mutations were detected in the exons and flaking introns of PAH gene of 44 families with classical phenylketonuria. 47 fetuses were diagnosed by combined sequencing with linkage analysis of three common short tandem repeats (STR) (PAH-STR, PAH-26 and PAH-32) in the PAH gene.

RESULTSThirty-one types of mutations were identified. A total of 84 mutations were identified in 88 alleles (95.45%), in which the most common mutation have been R243Q (21.59%), EX6-96A>G (6.82%), IVS4-1G>A (5.86%) and IVS7+2T>A (5.86%). Most mutations were found in exons 3, 5, 6, 7, 11 and 12. The polymorphism information content (PIC) of these three STR markers was 0.71 (PAH-STR), 0.48 (PAH-26) and 0.40 (PAH-32), respectively. Prenatal diagnosis was performed successfully with the combined method in 47 fetuses of 44 classical phenylketonuria families. Among them, 11 (23.4%) were diagnosed as affected, 24 (51.1%) as carriers, and 12 (25.5%) as unaffected.

CONCLUSIONPrenatal diagnosis can be achieved efficiently and accurately by stratified sequencing of PAH gene and linkage analysis of STR for classical phenylketonuria families.

Adolescent ; Adult ; Case-Control Studies ; Child ; Child, Preschool ; Female ; Fetal Diseases ; diagnosis ; enzymology ; genetics ; Genetic Testing ; Humans ; Infant ; Infant, Newborn ; Male ; Microsatellite Repeats ; Middle Aged ; Pedigree ; Phenylalanine Hydroxylase ; genetics ; Phenylketonurias ; diagnosis ; enzymology ; genetics ; Point Mutation ; Pregnancy ; Prenatal Diagnosis ; Young Adult

OBJECTIVETo study the characteristics of phenylalanine hydroxylase (PAH) gene mutations in patients with hyperphenylalaninemia from Jiangsu province by DNA sequencing, and to analyze the spectrum of PAH gene mutations.

METHODSA total of 70 patients and their parents were included in this study. All of the 13 exons and flanking introns of the PAH gene were analyzed with DNA sequencing.

RESULTSForty five types of mutations were identified, which included 4 novel mutations (L37P, H107R, Q267L, S391T). A total of 125 mutations were identified in 140 alleles (89.3%). All mutations were detected in exons 2-3, 5-7, 9-12 and introns 2, 4, 7 and 8. Most mutations were found in exons 6, 7 and 12. EX6-96A > G, R243Q and R241C were the most common mutations.

CONCLUSIONThe mutational spectrum of Jiangsu province seems to be different from other regions. The spectrum can offer reliable information for genetic diagnosis of patients with hyperphenylalaninemia.

Adult ; Base Sequence ; China ; Exons ; Female ; Humans ; Infant, Newborn ; Introns ; Male ; Molecular Sequence Data ; Mutation ; Phenylalanine Hydroxylase ; genetics ; Phenylketonurias ; enzymology ; genetics ; Young Adult

OBJECTIVETo study the mutations in exons 3, 6, 7, 11 and 12 of the phenylalanine hydroxylase gene (PAH) in Shanxi population.

METHODSThe mutations in exons 3, 6, 7, 11 and 12 and flanking sequences of PAH gene were detected by PCR-DNA sequencing, in 59 patients with phynelketonuria(PKU) and 100 healthy children from Shanxi province.

RESULTSBy sequence analysis, three single nucleotide polymorphism (SNP) Q232Q (CAA>CAG), V245V (GTG>GTA) and L385L (CTG>CTC) were detected in both the patients and healthy children, with the frequencies of nt 696, 735 and 1155 of the PAH cDNA up to 96.2%, 76.1% and 7.6% in patients respectively, and 97.0%, 77.3% and 8.3% respectively in the healthy controls. In addition, 72 different mutations accounting for 61.0% of mutant alleles were identified in the patients only. In exon 3, R111X, H64>TfsX9 and S70 del were found accounting for 5.1%, 0.8% and 0.8%; EX6-96A>G in exon 6 was found accounting for 10.2%. In exon 7, R243Q was the highest incidence accounting for 12.7%, followed by Ivs7+2 T>A(5.1%) and T278I(2.5%); the lowest incidences were G247V, R252Q, L255S, R261Q and E280K accounting for 0.8 %, respectively. In exon 11, Y356X (5.9%) and V399V (5.1%) were found; in exon 12, R413P and A434D were found accounting for 5.9% and 2.5%. In total, 9 missense mutations, 3 splice site mutations, 2 nonsense mutations and 2 deletions were included in 16 kinds of different mutations.

CONCLUSIONThe mutation characteristics and distribution in exons 3, 6, 7, 11 and 12 of the PAH gene have been identified, and it suggested that the EX6-96A>G and R243Q were the hot spots of PAH gene mutations in Shanxi PKU population.

Asian Continental Ancestry Group ; genetics ; Base Sequence ; Case-Control Studies ; China ; DNA Mutational Analysis ; Exons ; genetics ; Female ; Humans ; Infant ; Male ; Mutation ; Phenylalanine Hydroxylase ; genetics ; Phenylketonurias ; enzymology ; genetics ; Polymorphism, Single Nucleotide ; genetics

OBJECTIVETo study the characteristics of the phenylalanine hydroxylase gene (PAH) mutations in patients with phenylketonuria (PKU) in Henan province, in order to provide basic information for genetic counseling and prenatal diagnosis.

METHODSMutations of the PAH gene were detected in exons 1-13 with flanking introns of PAH gene by PCR and DNA sequencing in 47 families with PKU.

RESULTSA total of 25 different mutations were detected in 83 out of 94 PAH alleles (88.3%). Among them, E79fX13, H271R and D415Y have not been reported previously. It was the first time that IVS10-14C to G mutation was reported in Chinese PKU population. The mutations p.R243Q, EX6-96A to G, p.Y356X, IVS401G to A, p.R111X, p.V399V and p.R413P, were the prevalent mutations with relative frequencies of 20.5%, 12.0%, 9.6%, 9.6%, 8.4%, 8.4% and 7.2% respectively.

CONCLUSIONThe mutations of the PAH gene in patients with classical phenylketonuria in Henan province were similar to that in other areas of China. Prenatal gene diagnosis for PKU by PAH gene sequencing is efficient for most PKU families.

Base Sequence ; Child, Preschool ; China ; DNA Mutational Analysis ; methods ; Female ; Genetic Counseling ; methods ; Humans ; Male ; Molecular Sequence Data ; Phenylalanine Hydroxylase ; genetics ; Phenylketonurias ; diagnosis ; enzymology ; genetics ; Polymerase Chain Reaction ; methods ; Prenatal Diagnosis ; methods ; Sequence Analysis, DNA ; methods