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Molecular-genetic causes for the high frequency of phenylketonuria in the population from the North Caucasus. PLoS One 2018; 13:e0201489. [PMID: 30067850 PMCID: PMC6070269 DOI: 10.1371/journal.pone.0201489] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 07/15/2018] [Indexed: 01/25/2023] Open
Abstract
Phenylketonuria is an inherited disease caused by mutations in the phenylalanine hydroxylase gene PAH. Different PAH pathogenic variants occur in different ethnic groups with various frequencies and the incidence of the disease itself varies from country to country. In the Caucasus region of Russia, some ethnoses are geographically and culturally isolated from each other. The tradition of monoethnic marriages may cause decreased genetic variability in those populations. In the Karachay-Cherkess Republic (Russia), the highest incidence of phenylketonuria in the world has been detected (1:850 newborns) in the region and 1:332 among the titular nation Karachays. Here, we showed that this phenomenon is due to the widespread prevalence of the p.Arg261* variant. Its allele frequency among Karachay patients with PKU was 68.4% and the carrier frequency in Karachays was 1:16 healthy individuals. PAH haplotype analysis showed a unique common origin. The founder haplotype and mutation "age" were estimated by analyzing the linkage disequilibrium between p.Arg261* and extragenic short tandem repeat loci. The p.Arg261* variant occurred in the Karachays population 10.2 ± 2.7 generations ago (275 ± 73 years) and its spread occurred in parallel with the growth of the population.
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Garbade SF, Shen N, Himmelreich N, Haas D, Trefz FK, Hoffmann GF, Burgard P, Blau N. Allelic phenotype values: a model for genotype-based phenotype prediction in phenylketonuria. Genet Med 2018; 21:580-590. [DOI: 10.1038/s41436-018-0081-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 05/31/2018] [Indexed: 02/08/2023] Open
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Seifati SM, Nasirizadeh N, Azimzadeh M. Nano-biosensor based on reduced graphene oxide and gold nanoparticles, for detection of phenylketonuria-associated DNA mutation. IET Nanobiotechnol 2018; 12:417-422. [PMID: 29768223 PMCID: PMC8676255 DOI: 10.1049/iet-nbt.2017.0128] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 11/28/2017] [Accepted: 12/05/2017] [Indexed: 11/09/2023] Open
Abstract
Phenylketonuria (PKU)-associated DNA mutation in newborn children can be harmful to his health and early detection is the best way to inhibit consequences. A novel electrochemical nano-biosensor was developed for PKU detection, based on signal amplification using nanomaterials, e.g. gold nanoparticles (AuNPs) decorated on the reduced graphene oxide sheet on the screen-printed carbon electrode. The fabrication steps were checked by field emission scanning electron microscope imaging as well as cyclic voltammetry analysis. The specific alkanethiol single-stranded DNA probes were attached by self-assembly methodology on the AuNPs surface and Oracet blue was used as an intercalating electrochemical label. The results showed the detection limit of 21.3 fM and the dynamic range of 80-1200 fM. Moreover, the selectivity results represented a great specificity of the nano-biosensor for its specific target DNA oligo versus other non-specific sequences. The real sample simulation was performed successfully with almost no difference than a synthetic buffer solution environment.
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Affiliation(s)
- Seyed Morteza Seifati
- Medical Biotechnology Research Center, Ashkezar Branch, Islamic Azad University, 8941673155 Ashkezar, Yazd, Iran.
| | - Navid Nasirizadeh
- Department of Textile and Polymer Engineering, Yazd Branch, Islamic Azad University, 8916871967 Yazd, Iran
| | - Mostafa Azimzadeh
- Department of Advanced Medical Sciences and Technologies, School of Paramedicine, Shahid Sadoughi University of Medical Sciences, 8916188635 Yazd, Iran
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Zhang Z, Gao JJ, Feng Y, Zhu LL, Yan H, Shi XF, Chang AM, Shi Y, Wang P. Mutational spectrum of the phenylalanine hydroxylase gene in patients with phenylketonuria in the central region of China. Scand J Clin Lab Invest 2018; 78:211-218. [PMID: 29390883 DOI: 10.1080/00365513.2018.1434898] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 01/23/2018] [Accepted: 01/28/2018] [Indexed: 01/15/2023]
Abstract
Phenylketonuria (PKU, OMIM 261600) caused by phenylalanine hydroxylase (PAH) deficiency is an autosomal recessive disease that is characterized by abnormalities of phenylalanine metabolism. In this study, a total of 77 patients, originating from the central region of China and who were diagnosed with PAH deficiency at the third affiliated hospital of Zhengzhou University, were enrolled in this study. The 13 exons and 12 flanking introns of the PAH gene were analyzed by Sanger sequencing and next generation sequencing. The sequencing data were aligned to the hg19, PAHvdb and HGMD databases to characterize the genotypes of PKU patients, and genotype-phenotype correlations and BH4 responsiveness predictions were performed using BIOPKUdb. In total, 149 alleles were characterized among the 154 PKU alleles. These mutations were located in exons 2-13, and intron 12 of the PAH gene, with a relative frequency of ≥5%, for EX6-96A>G, p.R241C, p.R243Q, p.V399V and p.R53H. Additionally, a novel variant, p.D84G, was identified. The genotype correlated with clinical symptoms in 33.3-100% of the cases, depending on the disease severity, and BH4 responsiveness predictions show that only five patients with MHP-PKU and one patient with Mild-PKU were predicted to be BH4 responsive. In conclusion, we have characterized the mutational spectrum of PAH in the central region of China and have identified a novel mutation. The hotspot mutation information might be useful for screening, diagnosis and treatment of PKU.
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Affiliation(s)
- Zhan Zhang
- a The Third Affiliated Hospital of Zhengzhou University , Zhengzhou , China
- b Shangqiu Medical College , Shangqiu , China
| | - Jun-Jun Gao
- a The Third Affiliated Hospital of Zhengzhou University , Zhengzhou , China
| | - Yang Feng
- a The Third Affiliated Hospital of Zhengzhou University , Zhengzhou , China
| | - Lin-Lin Zhu
- c School of Laboratory Medicine , Xinxiang Medical University , Xinxiang , China
| | - Huan Yan
- a The Third Affiliated Hospital of Zhengzhou University , Zhengzhou , China
| | - Xu-Feng Shi
- d Department of Obstetrics , Henan Province People's Hospital , Zhengzhou , China
| | - Ai-Min Chang
- a The Third Affiliated Hospital of Zhengzhou University , Zhengzhou , China
| | - Ying Shi
- a The Third Affiliated Hospital of Zhengzhou University , Zhengzhou , China
| | - Ping Wang
- a The Third Affiliated Hospital of Zhengzhou University , Zhengzhou , China
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García-Carmona L, González MC, Escarpa A. Electrochemical On-site Amino Acids Detection of Maple Syrup Urine Disease Using Vertically Aligned Nickel Nanowires. ELECTROANAL 2018. [DOI: 10.1002/elan.201800103] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Laura García-Carmona
- Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, Faculty of Biology, Environmental Sciences and Chemistry; University of Alcalá; 28871 Alcalá de Henares Madrid Spain
| | - María Cristina González
- Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, Faculty of Biology, Environmental Sciences and Chemistry; University of Alcalá; 28871 Alcalá de Henares Madrid Spain
- Chemical Research Institute “Andrés M. del Río”; University of Alcalá; Alcalá de Henares E-28871 Madrid Spain
| | - Alberto Escarpa
- Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, Faculty of Biology, Environmental Sciences and Chemistry; University of Alcalá; 28871 Alcalá de Henares Madrid Spain
- Chemical Research Institute “Andrés M. del Río”; University of Alcalá; Alcalá de Henares E-28871 Madrid Spain
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Disruption of PTPS Gene Causing Pale Body Color and Lethal Phenotype in the Silkworm, Bombyx mori. Int J Mol Sci 2018; 19:ijms19041024. [PMID: 29596327 PMCID: PMC5979516 DOI: 10.3390/ijms19041024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 03/27/2018] [Accepted: 03/27/2018] [Indexed: 11/17/2022] Open
Abstract
Phenylketonuria (PKU) is an inborn error of metabolism caused by mutations in the phenylalanine hydroxylase (PAH) gene or by defects in the tetrahydrobiopterin (BH4) synthesis pathway. Here, by positional cloning, we report that the 6-pyruvoyl-tetrahydropterin synthase (PTPS) gene, encoding a key enzyme of BH4 biosynthesis, is responsible for the alc (albino C) mutation that displays pale body color, head shaking, and eventually lethality after the first molting in silkworm. Compared to wild type, the alc mutant produced more substrates (phenylalanine (Phe) and tyrosine (Tyr)) and generated less DOPA and dopamine. Application of 2,4-diamino-6-hydroxypyrimidine (DAHP) to block BH4 synthesis in the wild type effectively produced the alc-like phenotype, while BH4 supplementation rescued the defective body color and lethal phenotype in both alc and DAHP-treated individuals. The detection of gene expressions and metabolic substances after drugs treatments in alc and normal individuals imply that silkworms and humans have a high similarity in the drugs metabolic features and the gene pathway related to BH4 and the dopamine biosynthesis. We propose that the alc mutant could be used as an animal model for drug evaluation for BH4-deficient PKU.
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Wang R, Shen N, Ye J, Han L, Qiu W, Zhang H, Liang L, Sun Y, Fan Y, Wang L, Wang Y, Gong Z, Liu H, Wang J, Yan H, Blau N, Gu X, Yu Y. Mutation spectrum of hyperphenylalaninemia candidate genes and the genotype-phenotype correlation in the Chinese population. Clin Chim Acta 2018; 481:132-138. [PMID: 29499199 DOI: 10.1016/j.cca.2018.02.035] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 02/10/2018] [Accepted: 02/27/2018] [Indexed: 11/25/2022]
Abstract
BACKGROUND Hyperphenylalaninemia (HPA) is an inherited metabolic disorder that is caused by a deficiency of phenylalanine hydroxylase (PAH) or tetrahydrobiopterin. The prevalence of HPA varies widely around the world. METHODS A spectrum of HPA candidate genes in 1020 Chinese HPA patients was reported. Sanger sequencing, next generation sequencing (NGS), multiplex ligation-dependent probe amplification (MLPA) and quantitative real-time PCR (qRT-PCR) were applied to precisely molecular diagnose HPA patients. The allelic phenotype values (APV) and genotypic phenotype values (GPV) were calculated in PAH-deficient patients based on a recently developed formula. RESULTS Apart from genetic diagnoses confirmed in 915 HPA patients (89.7%) by Sanger sequencing, pathogenic variants were discovered in another 57 patients (5.6%) through deep detections (NGS, MLPA and qRT-PCR). We identified 196, 42, 10 and 2 variants in PAH, PTS, QDPR and GCH1, respectively. And a total of 47 novel variants were found in these genes. Through the APV and GPV calculations, it was found that the new GPV system was well correlated with metabolic phenotypes in most PAH-deficient patients. CONCLUSIONS More HPA candidate variants were identified using new molecular diagnostic methods. The new APV and GPV system is likely to be highly beneficial for predicting clinical phenotypes for PAH-deficient patients.
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Affiliation(s)
- Ruifang Wang
- Department of Pediatric Endocrinology and Genetic Metabolism, Shanghai Institute for Pediatric Research, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200092, China
| | - Nan Shen
- Department of Rehabilitation Medicine, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200092, China
| | - Jun Ye
- Department of Pediatric Endocrinology and Genetic Metabolism, Shanghai Institute for Pediatric Research, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200092, China
| | - Lianshu Han
- Department of Pediatric Endocrinology and Genetic Metabolism, Shanghai Institute for Pediatric Research, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200092, China
| | - Wenjuan Qiu
- Department of Pediatric Endocrinology and Genetic Metabolism, Shanghai Institute for Pediatric Research, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200092, China
| | - Huiwen Zhang
- Department of Pediatric Endocrinology and Genetic Metabolism, Shanghai Institute for Pediatric Research, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200092, China
| | - Lili Liang
- Department of Pediatric Endocrinology and Genetic Metabolism, Shanghai Institute for Pediatric Research, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200092, China
| | - Yu Sun
- Department of Pediatric Endocrinology and Genetic Metabolism, Shanghai Institute for Pediatric Research, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200092, China
| | - Yanjie Fan
- Department of Pediatric Endocrinology and Genetic Metabolism, Shanghai Institute for Pediatric Research, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200092, China
| | - Lili Wang
- Department of Pediatric Endocrinology and Genetic Metabolism, Shanghai Institute for Pediatric Research, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200092, China
| | - Yu Wang
- Department of Pediatric Endocrinology and Genetic Metabolism, Shanghai Institute for Pediatric Research, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200092, China
| | - Zhuwen Gong
- Department of Pediatric Endocrinology and Genetic Metabolism, Shanghai Institute for Pediatric Research, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200092, China
| | - Huili Liu
- Department of Pediatric Endocrinology and Genetic Metabolism, Shanghai Institute for Pediatric Research, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200092, China
| | - Jianguo Wang
- Department of Pediatric Endocrinology and Genetic Metabolism, Shanghai Institute for Pediatric Research, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200092, China
| | - Hui Yan
- Department of Pediatric Endocrinology and Genetic Metabolism, Shanghai Institute for Pediatric Research, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200092, China
| | - Nenad Blau
- Dietmar-Hopp Metabolic Center, University Children's Hospital, 69120 Heidelberg, Germany.
| | - Xuefan Gu
- Department of Pediatric Endocrinology and Genetic Metabolism, Shanghai Institute for Pediatric Research, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200092, China.
| | - Yongguo Yu
- Department of Pediatric Endocrinology and Genetic Metabolism, Shanghai Institute for Pediatric Research, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200092, China.
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Blau N, Martinez A, Hoffmann GF, Thöny B. DNAJC12 deficiency: A new strategy in the diagnosis of hyperphenylalaninemias. Mol Genet Metab 2018; 123:1-5. [PMID: 29174366 DOI: 10.1016/j.ymgme.2017.11.005] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 11/16/2017] [Accepted: 11/16/2017] [Indexed: 01/17/2023]
Abstract
Patients with hyperphenylalaninemia (HPA) are detected through newborn screening for phenylketonuria (PKU). HPA is known to be caused by deficiencies of the enzyme phenylalanine hydroxylase (PAH) or its cofactor tetrahydrobiopterin (BH4). Current guidelines for the differential diagnosis of HPA would, however, miss a recently described DNAJC12 deficiency. The co-chaperone DNAJC12 is, together with the 70kDa heat shock protein (HSP70), responsible for the proper folding of PAH. All DNAJC12-deficient patients investigated to date responded to a challenge with BH4 by lowering their blood phenylalanine levels. In addition, the patients presented with low levels of biogenic amine in CSF and responded to supplementation with BH4, L-dopa/carbidopa and 5-hydroxytryptophan. The phenotypic spectrum ranged from mild autistic features or hyperactivity to severe intellectual disability, dystonia and parkinsonism. Late diagnosis result in permanent neurological disability, while early diagnosed and treated patients develop normally. Molecular diagnostics for DNAJC12 variants are thus mandatory in all patients in which deficiencies of PAH and BH4 are genetically excluded.
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Affiliation(s)
- Nenad Blau
- Dietmar-Hopp-Metabolic Center, University Children's Hospital, Heidelberg, Germany.
| | - Aurora Martinez
- Department of Biomedicine and K.G. Jebsen Centre for Neuropsychiatric Disorders, University of Bergen, Bergen, Norway
| | - Georg F Hoffmann
- Dietmar-Hopp-Metabolic Center, University Children's Hospital, Heidelberg, Germany
| | - Beat Thöny
- Division of Metabolism, University Children's Hospital Zürich, Zürich, Switzerland
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Liu N, Huang Q, Li Q, Zhao D, Li X, Cui L, Bai Y, Feng Y, Kong X. Spectrum of PAH gene variants among a population of Han Chinese patients with phenylketonuria from northern China. BMC MEDICAL GENETICS 2017; 18:108. [PMID: 28982351 PMCID: PMC5629770 DOI: 10.1186/s12881-017-0467-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 09/27/2017] [Indexed: 12/14/2022]
Abstract
Background Phenylketonuria (PKU), which primarily results from a deficiency of phenylalanine hydroxylase (PAH), is one of the most common inherited inborn errors of metabolism that impairs postnatal cognitive development. The incidence of various PAH variations differs by race and ethnicity. The aim of the present study was to characterize the PAH gene variants of a Han population from Northern China. Methods In total, 655 PKU patients and their families were recruited for this study; each proband was diagnosed both clinically and biochemically with phenylketonuria. Subjects were sequentially screened for single-base variants and exon deletions or duplications within PAH via direct Sanger sequencing and multiplex ligation-dependent probe amplification (MLPA). Results A spectrum of 174 distinct PAH variants was identified: 152 previously documented variants and 22 novel variants. While single-base variants were distributed throughout the 13 exons, they were particularly concentrated in exons 7 (33.3%), 11 (14.2%), 6 (13.2%), 12 (11.0%), 3 (10.4%), and 5 (4.4%). The predominant variant was p.Arg243Gln (17.7%), followed by Ex6-96A > G (8.3%), p.Val399 = (6.4%), p.Arg53His (4.7%), p.Tyr356* (4.7%), p.Arg241Cys (4.6%), p.Arg413Pro (4.6%), p.Arg111* (4.4%), and c.442-1G > A (3.4%). Notably, two patients were also identified as carrying de novo variants. Conclusion The composition of PAH gene variants in this Han population from Northern China was distinct from those of other ethnic groups. As such, the construction of a PAH gene variant database for Northern China is necessary to lay a foundation for genetic-based diagnoses, prenatal diagnoses, and population screening. Electronic supplementary material The online version of this article (10.1186/s12881-017-0467-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ning Liu
- Genetics and Prenatal Diagnosis Center, The First Affiliated Hospital of Zhengzhou University, Henan Engineering Research Center for Gene Editing of Human Genetic Disease, Jianshe Rd, Erqi District, Zhengzhou, Henan, 450052, People's Republic of China
| | - Qiuying Huang
- State Key Laboratory of Cellular Stress Biology, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, Engineering Research Centre of Molecular Diagnostics, Ministry of Education, School of Life Sciences, Xiamen University, Xiangan Rd, Xiangan District, Xiamen, Fujian, 361102, People's Republic of China
| | - Qingge Li
- State Key Laboratory of Cellular Stress Biology, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, Engineering Research Centre of Molecular Diagnostics, Ministry of Education, School of Life Sciences, Xiamen University, Xiangan Rd, Xiangan District, Xiamen, Fujian, 361102, People's Republic of China
| | - Dehua Zhao
- Neonatal Screening Center, The Third Affiliated Hospital of Zhengzhou University, Kangfu Rd, Erqi District, Zhengzhou, Henan, 450052, People's Republic of China
| | - Xiaole Li
- Neonatal Screening Center, The Third Affiliated Hospital of Zhengzhou University, Kangfu Rd, Erqi District, Zhengzhou, Henan, 450052, People's Republic of China
| | - Lixia Cui
- Neonatal Screening Center, Zhengzhou Maternity and Child Care Hospital, Jinshui Rd, Jinshui District, Zhengzhou, Henan, 450012, People's Republic of China
| | - Ying Bai
- Genetics and Prenatal Diagnosis Center, The First Affiliated Hospital of Zhengzhou University, Henan Engineering Research Center for Gene Editing of Human Genetic Disease, Jianshe Rd, Erqi District, Zhengzhou, Henan, 450052, People's Republic of China
| | - Yin Feng
- Genetics and Prenatal Diagnosis Center, The First Affiliated Hospital of Zhengzhou University, Henan Engineering Research Center for Gene Editing of Human Genetic Disease, Jianshe Rd, Erqi District, Zhengzhou, Henan, 450052, People's Republic of China
| | - Xiangdong Kong
- Genetics and Prenatal Diagnosis Center, The First Affiliated Hospital of Zhengzhou University, Henan Engineering Research Center for Gene Editing of Human Genetic Disease, Jianshe Rd, Erqi District, Zhengzhou, Henan, 450052, People's Republic of China.
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Gundorova P, Zinchenko RA, Makaov AK, Polyakov AV. The spectrum of mutations in the PAH gene in patients with hyperphenylalaninemia from the Karachay-Cherkess Republic. RUSS J GENET+ 2017. [DOI: 10.1134/s1022795417070043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Hawks Z, Shimony J, Rutlin J, Grange DK, Christ SE, White DA. Pretreatment cognitive and neural differences between sapropterin dihydrochloride responders and non-responders with phenylketonuria. Mol Genet Metab Rep 2017; 12:8-13. [PMID: 28271047 PMCID: PMC5323508 DOI: 10.1016/j.ymgmr.2017.01.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 01/28/2017] [Indexed: 12/02/2022] Open
Abstract
Sapropterin dihydrochloride (BH4) reduces phenylalanine (Phe) levels and improves white matter integrity in a subset of individuals with phenylketonuria (PKU) known as “responders.” Although prior research has identified biochemical and genotypic differences between BH4 responders and non-responders, cognitive and neural differences remain largely unexplored. To this end, we compared intelligence and white matter integrity prior to treatment with BH4 in 13 subsequent BH4 responders with PKU, 16 subsequent BH4 non-responders with PKU, and 12 healthy controls. Results indicated poorer intelligence and white matter integrity in non-responders compared to responders prior to treatment. In addition, poorer white matter integrity was associated with greater variability in Phe across the lifetime in non-responders but not in responders. These results underscore the importance of considering PKU as a multi-faceted, multi-dimensional disorder and point to the need for additional research to delineate characteristics that predict response to treatment with BH4.
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Affiliation(s)
- Zoë Hawks
- Department of Psychological and Brain Sciences, Campus Box 1125, Washington University, St. Louis, MO 63130, USA
| | - Joshua Shimony
- Mallinckrodt Institute of Radiology, Campus Box 8131, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Jerrel Rutlin
- Mallinckrodt Institute of Radiology, Campus Box 8131, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Dorothy K Grange
- Department of Pediatrics, Campus Box 8116, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Shawn E Christ
- Department of Psychological Sciences, 210 McAlester Hall, University of Missouri, Columbia, MO 65211, USA
| | - Desirée A White
- Department of Psychological and Brain Sciences, Campus Box 1125, Washington University, St. Louis, MO 63130, USA; Department of Pediatrics, Campus Box 8116, Washington University School of Medicine, St. Louis, MO 63110, USA
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Gundorova P, Stepanova AA, Makaov AK, Zinchenko RA, Abaykhanova ZM, Polyakov AV. Mutation spectrum of the PAH gene in phenylketonuria patients in the Karachay-Cherkess Republic (Russia). RUSS J GENET+ 2016. [DOI: 10.1134/s1022795416110041] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Trunzo R, Santacroce R, Shen N, Jung-Klawitter S, Leccese A, De Girolamo G, Margaglione M, Blau N. In vitro residual activity of phenylalanine hydroxylase variants and correlation with metabolic phenotypes in PKU. Gene 2016; 594:138-143. [PMID: 27620137 DOI: 10.1016/j.gene.2016.09.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 08/29/2016] [Accepted: 09/08/2016] [Indexed: 10/21/2022]
Abstract
Hyperphenylalaninemias (HPAs) are genetic diseases predominantly caused by a wide range of variants in the phenylalanine hydroxylase (PAH) gene. In vitro expression analysis of PAH variants offers the opportunity to elucidate the molecular mechanisms involved in HPAs and to clarify whether a disease-associated variant is genuinely pathogenic, while investigating the severity of a metabolic phenotype, and determining how a variant exerts its deleterious effects on the PAH enzyme. To study the effects of gene variants on PAH activity, we investigated eight variants: c.611A>G (p.Y204C), c.635T>C (p.L212P), c.746T>C (p.L249P), c.745C>T (p.L249F), c.809G>A (p.R270K), c.782G>C (p.R261P), c.587C>A (p.S196Y) and c.1139C>T (p.T380M), associated with different phenotypic groups. Transient expression of mutant full-length cDNAs in COS-7 cells yielded PAH proteins with PAH activity levels between 7% and 51% compared to the wild-type enzyme. With one exception (p.Y204C, which had no significant impact on PAH function), lower PAH activity was associated with a more severe phenotype (e.g. p.L249P with 7% PAH activity, 100% of classic PKU and no BH4 responsiveness), while higher activity correlated with milder phenotypes (e.g. p.T380M with 28% PAH activity, 97% of mild HPA and 83% of BH4 responsiveness). The results of the in vitro residual PAH activity have major implications, both for our understanding of genotype-phenotype correlations, and thereby existing inconsistencies, but also for the elucidation of the molecular basis of tetrahydrobiopterin (BH4) responsiveness.
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Affiliation(s)
- Roberta Trunzo
- Genetica Medica, Dipartimento di Medicina Clinica e Sperimentale, Università degli Studi di Foggia, Italy.
| | - Rosa Santacroce
- Genetica Medica, Dipartimento di Medicina Clinica e Sperimentale, Università degli Studi di Foggia, Italy
| | - Nan Shen
- Dietmar-Hopp Metabolic Center, University Children's Hospital, Department of General Pediatrics, Heidelberg, Germany
| | - Sabine Jung-Klawitter
- Dietmar-Hopp Metabolic Center, University Children's Hospital, Department of General Pediatrics, Heidelberg, Germany
| | - Angelica Leccese
- Genetica Medica, Dipartimento di Medicina Clinica e Sperimentale, Università degli Studi di Foggia, Italy
| | - Giuseppe De Girolamo
- Genetica Medica, Dipartimento di Medicina Clinica e Sperimentale, Università degli Studi di Foggia, Italy
| | - Maurizio Margaglione
- Genetica Medica, Dipartimento di Medicina Clinica e Sperimentale, Università degli Studi di Foggia, Italy
| | - Nenad Blau
- Dietmar-Hopp Metabolic Center, University Children's Hospital, Department of General Pediatrics, Heidelberg, Germany
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CRISPR RNA-guided FokI nucleases repair a PAH variant in a phenylketonuria model. Sci Rep 2016; 6:35794. [PMID: 27786189 PMCID: PMC5081532 DOI: 10.1038/srep35794] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 10/05/2016] [Indexed: 01/17/2023] Open
Abstract
The CRISPR/Cas9 system is a recently developed genome editing technique. In this study, we used a modified CRISPR system, which employs the fusion of inactive Cas9 (dCas9) and the FokI endonuclease (FokI-dCas9) to correct the most common variant (allele frequency 21.4%) in the phenylalanine hydroxylase (PAH) gene - c.1222C>T (p.Arg408Trp) - as an approach toward curing phenylketonuria (PKU). PKU is the most common inherited diseases in amino acid metabolism. It leads to severe neurological and neuropsychological symptoms if untreated or late diagnosed. Correction of the disease-causing variants could rescue residual PAH activity and restore normal function. Co-expression of a single guide RNA plasmid, a FokI-dCas9-zsGreen1 plasmid, and the presence of a single-stranded oligodeoxynucleotide in PAH_c.1222C>T COS-7 cells – an in vitro model for PKU – corrected the PAH variant and restored PAH activity. Also in this system, the HDR enhancer RS-1 improved correction efficiency. This proof-of-concept indicates the potential of the FokI-dCas9 system for precision medicine, in particular for targeting PKU and other monogenic metabolic diseases.
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Phenylketonuria and Gut Microbiota: A Controlled Study Based on Next-Generation Sequencing. PLoS One 2016; 11:e0157513. [PMID: 27336782 PMCID: PMC4918959 DOI: 10.1371/journal.pone.0157513] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 05/30/2016] [Indexed: 02/07/2023] Open
Abstract
Phenylketonuria (PKU) is an inborn error of metabolism associated with high blood levels of phenylalanine (Phe). A Phe-restricted diet supplemented with L-amino acids is the main treatment strategy for this disease; if started early, most neurological abnormalities can be prevented. The healthy human gut contains trillions of commensal bacteria, often referred to as the gut microbiota. The composition of the gut microbiota is known to be modulated by environmental factors, including diet. In this study, we compared the gut microbiota of 8 PKU patients on Phe-restricted dietary treatment with that of 10 healthy individuals. The microbiota were characterized by 16S rRNA sequencing using the Ion Torrent™ platform. The most dominant phyla detected in both groups were Bacteroidetes and Firmicutes. PKU patients showed reduced abundance of the Clostridiaceae, Erysipelotrichaceae, and Lachnospiraceae families, Clostridiales class, Coprococcus, Dorea, Lachnospira, Odoribacter, Ruminococcus and Veillonella genera, and enrichment of Prevotella, Akkermansia, and Peptostreptococcaceae. Microbial function prediction suggested significant differences in starch/glucose and amino acid metabolism between PKU patients and controls. Together, our results suggest the presence of distinct taxonomic groups within the gut microbiome of PKU patients, which may be modulated by their plasma Phe concentration. Whether our findings represent an effect of the disease itself, or a consequence of the modified diet is unclear.
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66
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Variants of uncertain significance in newborn screening disorders: implications for large-scale genomic sequencing. Genet Med 2016; 19:77-82. [DOI: 10.1038/gim.2016.67] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 04/11/2016] [Indexed: 12/24/2022] Open
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Abstract
More than 950 phenylalanine hydroxylase (PAH) gene variants have been identified in people with phenylketonuria (PKU). These vary in their consequences for the residual level of PAH activity, from having little or no effect to abolishing PAH activity completely. Advances in genotyping technology and the availability of locus-specific and genotype databases have greatly expanded our understanding of the correlations between individual gene variant, residual PAH activity, tetrahydrobiopterin (BH4 ) responsiveness, and the clinical PKU phenotype. Most patients (∼76%) have compound heterozygous PAH gene variants and one mutated allele may markedly influence the activity of the second mutated allele, which in turn may influence either positively or negatively the activity of the biologically active heterotetrameric form of the PAH. While it is possible to predict the level of BH4 responsiveness (∼71%) and PKU severity (∼78%) from the nature of the underlying gene variants, these relationships remain complex and incompletely understood. A greater understanding of these relationships may increase the potential for individualized management of PKU in future. Inherited deficiencies in BH4 metabolism account for about 1%-2% of all hyperphenylalaninemias and are clinically more severe than PKU. Almost 90% of all patients are deficient in 6-pyruvoyl-tetrahydropterin synthase and dihydropteridine reductase.
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Affiliation(s)
- Nenad Blau
- Dietmar-Hopp-Metabolic Center, University Children's Hospital, Heidelberg, Germany
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Aldámiz-Echevarría L, Llarena M, Bueno MA, Dalmau J, Vitoria I, Fernández-Marmiesse A, Andrade F, Blasco J, Alcalde C, Gil D, García MC, González-Lamuño D, Ruiz M, Ruiz MA, Peña-Quintana L, González D, Sánchez-Valverde F, Desviat LR, Pérez B, Couce ML. Molecular epidemiology, genotype-phenotype correlation and BH4 responsiveness in Spanish patients with phenylketonuria. J Hum Genet 2016; 61:731-44. [PMID: 27121329 DOI: 10.1038/jhg.2016.38] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 03/16/2016] [Accepted: 03/24/2016] [Indexed: 01/26/2023]
Abstract
Phenylketonuria (PKU), the most common inborn error of amino acid metabolism, is caused by mutations in the phenylalanine-4-hydroxylase (PAH) gene. This study aimed to assess the genotype-phenotype correlation in the PKU Spanish population and the usefulness in establishing genotype-based predictions of BH4 responsiveness in our population. It involved the molecular characterization of 411 Spanish PKU patients: mild hyperphenylalaninemia non-treated (mild HPA-NT) (34%), mild HPA (8.8%), mild-moderate (20.7%) and classic (36.5%) PKU. BH4 responsiveness was evaluated using a 6R-BH4 loading test. We assessed genotype-phenotype associations and genotype-BH4 responsiveness in our population according to literature and classification of the mutations. The mutational spectrum analysis showed 116 distinct mutations, most missense (70.7%) and located in the catalytic domain (62.9%). The most prevalent mutations were c.1066-11G>A (9.7%), p.Val388Met (6.6%) and p.Arg261Gln (6.3%). Three novel mutations (c.61-13del9, p.Ile283Val and p.Gly148Val) were reported. Although good genotype-phenotype correlation was observed, there was no exact correlation for some genotypes. Among the patients monitored for the 6R-BH4 loading test: 102 were responders (87, carried either one or two BH4-responsive alleles) and 194 non-responders (50, had two non-responsive mutations). More discrepancies were observed in non-responders. Our data reveal a great genetic heterogeneity in our population. Genotype is quite a good predictor of phenotype and BH4 responsiveness, which is relevant for patient management, treatment and follow-up.
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Affiliation(s)
- Luis Aldámiz-Echevarría
- Unit of Metabolism, Cruces University Hospital, BioCruces Health Research Institute, GCV-CIBER de Enfermedades Raras (CIBERER), Plaza de Cruces s/n, Barakaldo, Spain
| | - Marta Llarena
- Unit of Metabolism, Cruces University Hospital, BioCruces Health Research Institute, GCV-CIBER de Enfermedades Raras (CIBERER), Plaza de Cruces s/n, Barakaldo, Spain
| | - María A Bueno
- Metabolic Disorders, Dietetics and Nutrition Unit, Virgen del Rocío University Hospital, Manuel Siurot Avenue s/n, Sevilla, Spain
| | - Jaime Dalmau
- Nutrition and Metabolopathologies Unit, La Fe University Hospital, Bulevar Sur s/n, Valencia, Spain
| | - Isidro Vitoria
- Nutrition and Metabolopathologies Unit, La Fe University Hospital, Bulevar Sur s/n, Valencia, Spain
| | - Ana Fernández-Marmiesse
- Unit of Diagnosis and Treatment of Congenital Metabolic Diseases, Department of Pediatrics, Hospital Clínico Universitario de Santiago de Compostela, CIBERER, Health Research Institute of Santiago de Compostela (IDIS), A Choupana, s/n, Santiago de Compostela, A Coruña, Spain
| | - Fernando Andrade
- Unit of Metabolism, Cruces University Hospital, BioCruces Health Research Institute, GCV-CIBER de Enfermedades Raras (CIBERER), Plaza de Cruces s/n, Barakaldo, Spain
| | - Javier Blasco
- Gastroenterology, Hepatology and Child Nutrition Unit, Carlos Haya University Hospital, Avda. Arroyo de los Ángeles s/n, Málaga, Spain
| | - Carlos Alcalde
- Paediatrics Unit, Río Hortega University Hospital, Valladolid, Spain
| | - David Gil
- Gastroenterology Unit, Virgen de la Arrixaca University Hospital, Ctra. Madrid-Cartagena s/n, El Palmar, Murcia, Spain
| | - María C García
- Metabolic Pathologies Unit, Miguel Servet University Hospital, Zaragoza, Spain
| | | | - Mónica Ruiz
- Paediatrics Unit, Nuestra Señora de la Candelaria University Hospital, Santa Cruz de Tenerife, Spain
| | - María A Ruiz
- Metabolic Pathologies and Neuropaediatrics Unit, Son Espases University Hospital, Palma de Mallorca, Spain
| | - Luis Peña-Quintana
- Paediatric Gastroenterology, Hepatology and Nutrition Unit, Mother and Child Hospital Complex, Avda. Marítima del Sur s/n, Las Palmas de Gran Canaria, Spain
| | - David González
- Metabolic Pathologies Unit, Maternal and Child Hospital, Badajoz, Spain
| | - Felix Sánchez-Valverde
- Gastroenterology and Paediatric Nutrition Unit, Virgen del Camino Hospital, Pamplona, Spain
| | - Lourdes R Desviat
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular Severo Ochoa CSIC-UAM, CIBERER, IdiPaz, Madrid, Spain
| | - Belen Pérez
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular Severo Ochoa CSIC-UAM, CIBERER, IdiPaz, Madrid, Spain
| | - María L Couce
- Unit of Diagnosis and Treatment of Congenital Metabolic Diseases, Department of Pediatrics, Hospital Clínico Universitario de Santiago de Compostela, CIBERER, Health Research Institute of Santiago de Compostela (IDIS), A Choupana, s/n, Santiago de Compostela, A Coruña, Spain
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Shen N, Heintz C, Thiel C, Okun JG, Hoffmann GF, Blau N. Co-expression of phenylalanine hydroxylase variants and effects of interallelic complementation on in vitro enzyme activity and genotype-phenotype correlation. Mol Genet Metab 2016; 117:328-35. [PMID: 26803807 DOI: 10.1016/j.ymgme.2016.01.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 01/09/2016] [Indexed: 02/04/2023]
Abstract
BACKGROUND In phenylketonuria (PKU) patients, the combination of two phenylalanine hydroxylase (PAH) alleles is the main determinant of residual enzyme activity in vivo and in vitro. Inconsistencies in genotype-phenotype correlations have been observed in compound heterozygous patients and a particular combination of two PAH alleles may produce a phenotype that is different from the expected one, possibly due to interallelic complementation. METHODS A dual eukaryotic vector system with two distinct PAH proteins N-terminally fused to different epitope tags was used to investigate the co-expression of PAH alleles reported in patients with inconsistent phenotypes. PAH variant proteins were transiently co-transfected in COS-7 cells. PAH activity was measured by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS-MS), and protein expression was measured by Western blot. Genotypes were compared with predicted PAH activity from the PAH locus-specific database (PAHvdb) and with phenotypes and tetrahydrobiopterin (BH4) responsiveness from more than 10,000 PKU patients (BIOPKU database). RESULTS Through the expression and co-expression of 17 variant alleles we demonstrated that interallelic interaction could be both positive and negative. The co-expressions of p.[I65T];[R261Q] (19.5% activity; predicted 43.5%) and p.[I65T];[R408W] (15.0% vs. 26.8% activity) are examples of genotypes with negative interallelic interaction. The co-expressions of p.[E178G];[Q232E] (55.0% vs.36.4%) and p.[P384S];[R408W] (56.1% vs. 40.8%) are examples of positive subunit interactions. Inconsistencies of PAH residual enzyme activity in vitro and of PKU patients' phenotypes were observed as well. The PAH activity of p.[R408W];[A300S] is 18.0% of the wild-type activity; however, 88% of patients with this genotype exhibit mild hyperphenylalaninemias (MHPs). CONCLUSION The co-expression of two distinct PAH variants revealed possible dominance effects (positive or negative) by one of the variants on residual PAH activity as a result of interallelic complementation.
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Affiliation(s)
- Nan Shen
- Dietmar-Hopp Metabolic Center, University Children's Hospital, Department of General Pediatrics, Heidelberg, Germany
| | - Caroline Heintz
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, United States
| | - Christian Thiel
- Dietmar-Hopp Metabolic Center, University Children's Hospital, Department of General Pediatrics, Heidelberg, Germany
| | - Jürgen G Okun
- Dietmar-Hopp Metabolic Center, University Children's Hospital, Department of General Pediatrics, Heidelberg, Germany
| | - Georg F Hoffmann
- Dietmar-Hopp Metabolic Center, University Children's Hospital, Department of General Pediatrics, Heidelberg, Germany
| | - Nenad Blau
- Dietmar-Hopp Metabolic Center, University Children's Hospital, Department of General Pediatrics, Heidelberg, Germany.
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Diagnostic and management practices for phenylketonuria in 19 countries of the South and Eastern European Region: survey results. Eur J Pediatr 2016; 175:261-72. [PMID: 26350228 PMCID: PMC4724370 DOI: 10.1007/s00431-015-2622-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 08/10/2015] [Accepted: 08/14/2015] [Indexed: 01/17/2023]
Abstract
UNLABELLED To avoid potentially severe outcomes, phenylketonuria (PKU) must be detected as soon as possible after birth and managed with life-long treatment. A questionnaire-based survey was performed to document diagnosis and management practices for PKU in a region of Southern and Eastern Europe. Prevalence and management data were obtained from 37/59 (63 %) centres within 19/22 (86%) contacted countries (N = 8600 patients). The main results' analysis was based on completed questionnaires obtained from 31 centres (53%) within 15 countries (68%). A median of 10 % of patients per centre had been diagnosed after the newborn period. Metabolic dieticians and specialised adult PKU clinics were lacking in 36 and 84% of centres, respectively. In 26% of centres, treatment initiation was delayed until >15 days of life. Blood phenylalanine (Phe) thresholds to start treatment and upper Phe targets were inconsistent across centres. Ten percent of centres reported monitoring Phe every 2 weeks for pregnant women with PKU, which is insufficient to minimise risk of neonatal sequalae. Sapropterin dihydrochloride treatment was available in 48% of centres, with 24-h responsiveness tests most common (36%). Only one centre among the five countries lacking newborn screening provided a completed questionnaire. CONCLUSION Targeted efforts by health care professionals and governments are needed to optimise diagnostic and management approaches for PKU in Southern and Eastern Europe. WHAT IS KNOWN PKU must be detected early and optimally managed throughout life to avoid poor outcomes, yet newborn screening is not universal and diagnostic and management practices for PKU are known to vary widely between different centres and countries. Targeted efforts by health care professionals and governments are needed to optimise diagnostic and management approaches. WHAT IS NEW PKU management practices are documented in 19 South and Eastern European countries indicating a heterogeneous situation across the region. Key areas for improvement identified in surveyed centres include a need for comprehensive screening in all countries, increased number of metabolic dietitians and specialised adult PKU clinics, delayed time to treatment initiation, appropriate Phe thresholds, Phe targets and monitoring frequencies, and universal access to currently available treatment options.
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71
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Tao J, Li N, Jia H, Liu Z, Li X, Song J, Deng Y, Jin X, Zhu J. Correlation between genotype and the tetrahydrobiopterin-responsive phenotype in Chinese patients with phenylketonuria. Pediatr Res 2015; 78:691-9. [PMID: 26322415 PMCID: PMC4700046 DOI: 10.1038/pr.2015.167] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2015] [Accepted: 06/17/2015] [Indexed: 01/30/2023]
Abstract
BACKGROUND A growing body of research has suggested that tetrahydrobiopterin (BH4) responsive phenotype can be predicted by the phenylalanine hydroxylase (PAH) genotype in patients with phenylketonuria (PKU), but data concerning the association between genotype and BH4 responsiveness are scarce in China. METHODS A total of 165 PKU patients from China who had undergone a 24-h loading test with BH4 administration were recruited. Genotyping was performed by the next-generation sequencing (NGS) technique. Using the predicted residual PAH activity, we analyzed the association between genotype and BH4-responsiveness. RESULTS Among the 165 patients, 40 patients (24.24%) responded to BH4. A total of 74 distinct mutations were observed, including 13 novel mutations. The mutation p.R241C was most frequently associated with response. Two known mutations (p.A322T and p.Q419R) and two novel mutations (p.L98V and IVS3-2A>T) were first reported as responsive to BH4. Residual PAH activity of at least 12.5% was needed for responsive genotypes. CONCLUSION Genotype-based predictions of BH4-responsiveness are only for selecting potential responders. Accordingly, it is necessary to test potential responders with a long-term BH4 challenge.
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Affiliation(s)
- Jing Tao
- National Centre for Birth Defect Monitoring, West China Second University Hospital, Sichuan University, Sichuan, China
- West China School of Public Health, Sichuan University, Sichuan, China
| | - Nana Li
- National Centre for Birth Defect Monitoring, West China Second University Hospital, Sichuan University, Sichuan, China
- Laboratory of Molecular Epidemiology for Birth Defects, West China Second University Hospital, Sichuan University, Sichuan, China
| | - Haitao Jia
- BGI-Shenzhen, Shenzhen, Guangdong, China
| | - Zhen Liu
- National Centre for Birth Defect Monitoring, West China Second University Hospital, Sichuan University, Sichuan, China
- Laboratory of Molecular Epidemiology for Birth Defects, West China Second University Hospital, Sichuan University, Sichuan, China
| | - Xiaohong Li
- National Centre for Birth Defect Monitoring, West China Second University Hospital, Sichuan University, Sichuan, China
- Laboratory of Molecular Epidemiology for Birth Defects, West China Second University Hospital, Sichuan University, Sichuan, China
| | | | - Ying Deng
- National Centre for Birth Defect Monitoring, West China Second University Hospital, Sichuan University, Sichuan, China
- Laboratory of Molecular Epidemiology for Birth Defects, West China Second University Hospital, Sichuan University, Sichuan, China
| | - Xi Jin
- National Centre for Birth Defect Monitoring, West China Second University Hospital, Sichuan University, Sichuan, China
- Laboratory of Molecular Epidemiology for Birth Defects, West China Second University Hospital, Sichuan University, Sichuan, China
| | - Jun Zhu
- National Centre for Birth Defect Monitoring, West China Second University Hospital, Sichuan University, Sichuan, China
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Gemperle-Britschgi C, Iorgulescu D, Mager MA, Anton-Paduraru D, Vulturar R, Thöny B. A novel common large genomic deletion and two new missense mutations identified in the Romanian phenylketonuria population. Gene 2015; 576:182-8. [PMID: 26481238 DOI: 10.1016/j.gene.2015.10.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 06/02/2015] [Accepted: 10/12/2015] [Indexed: 10/22/2022]
Abstract
The mutation spectrum for the phenylalanine hydroxylase (PAH) gene was investigated in a cohort of 84 hyperphenylalaninemia (HPA) patients from Romania identified through newborn screening or neurometabolic investigations. Differential diagnosis identified 81 patients with classic PAH deficiency while 3 had tetrahydropterin-cofactor deficiency and/or remained uncertain due to insufficient specimen. PAH-genetic analysis included a combination of Sanger sequencing of exons and exon–intron boundaries, MLPA and NGS with genomic DNA, and cDNA analysis from immortalized lymphoblasts. A diagnostic efficiency of 99.4% was achieved, as for one allele (out of a total of 162 alleles) no mutation could be identified. The most prevalent mutation was p.Arg408Trp which was found in ~ 38% of all PKU alleles. Three novel mutations were identified, including the two missense mutations p.Gln226Lys and p.Tyr268Cys that were both disease causing by prediction algorithms, and the large genomic deletion EX6del7831 (c.509 + 4140_706 + 510del7831) that resulted in skipping of exon 6 based on PAH-cDNA analysis in immortalized lymphocytes. The genomic deletion was present in a heterozygous state in 12 patients, i.e. in ~ 8% of all the analyzed PKU alleles, and might have originated from a Romanian founder.
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Affiliation(s)
- Corinne Gemperle-Britschgi
- Division of Clinical Chemistry and Biochemistry, Department of Pediatrics, University of Zürich, Zürich, Switzerland
| | - Daniela Iorgulescu
- Center of Newborn Screening, Department of Pediatrics, Institute for Mother and Child Care, Bucharest, 120 Lacul Tei Blv., 020395, Romania
| | - Monica Alina Mager
- "I. Hatieganu" University of Medicine and Pharmacy - Cluj-Napoca, Department of Neurology, Romania
| | - Dana Anton-Paduraru
- "Gr.T.Popa" University of Medicine and Pharmacy, Newborn Screening Center Iasi, 3rd Clinic of Pediatrics, Romania
| | - Romana Vulturar
- "I.Hatieganu" University of Medicine and Pharmacy - Cluj-Napoca, Department of Molecular Sciences, Cluj-Napoca, Romania; Cognitive Neuroscience Laboratory, Babes-Bolyai University - Cluj-Napoca, Romania.
| | - Beat Thöny
- Division of Clinical Chemistry and Biochemistry, Department of Pediatrics, University of Zürich, Zürich, Switzerland; Division of Metabolism, Department of Pediatrics, University of Zurich, Steinwiesstrasse 75, Zurich CH-8032, Switzerland; Neuroscience Centre Zürich, University of Zürich, Zürich, Switzerland; Neuroscience Centre Zürich, ETH Zürich (ZNZ), Zürich, Switzerland; Children's Research Centre (CRC), Zürich, Switzerland.
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Chen YF, Jia HT, Chen ZH, Song JP, Liang Y, Pei JJ, Wu ZJ, Wang J, Qiu YL, Liu G, Sun DM, Jiang XY. Mutational spectrum of phenylketonuria in Jiangsu province. Eur J Pediatr 2015; 174:1333-8. [PMID: 25894915 DOI: 10.1007/s00431-015-2539-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 04/01/2015] [Accepted: 04/06/2015] [Indexed: 12/22/2022]
Abstract
UNLABELLED Phenylketonuria (PKU) is caused by variants in the phenylalanine hydroxylase (PAH) gene. We systematically investigated all 13 exons of the PAH gene and their flanking introns in 31 unrelated patients and their parents using next-generation sequencing (NGS). A total of 33 different variants were identified in 58 of 62 mutant PAH alleles. The prevalent variants with a relative frequency of 5 % or more were c.721C > T, c.1068C > A, c.611A > G, c.1197A > T, c.728G > A, c.331C > T, and c.442-1G > A. One novel variant was identified in this study-c.699C > G. We studied genotype-phenotype correlations using the Guldberg arbitrary value (AV) system, which revealed a consistency rate of 38 % (8/21) among the 21 predicted phenotypes. The genotype-based prediction of BH4 responsiveness was also evaluated, and 14 patients (45.2 %) were predicted to be BH4 responsive. CONCLUSION This study presents the spectrum of PAH variants in Jiangsu province. The information obtained from the genotype-based prediction of BH4 responsiveness might be used for the rational selection of candidates for BH4 testing. WHAT IS KNOWN • Phenylketonuria (PKU) is caused by variants in the phenylalanine hydroxylase (PAH) gene. • The spectrum of PAH variants in different Chinese populations has been reported. What is new: • This is the first report on the spectrum of PAH variants in Jiangsu province. • This study identified one novel PAH variant-c.699C>G-and and tries to show a genotype-phenotype relationship also regarding BH4-responsiveness.
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Affiliation(s)
- Ya-fen Chen
- Department of Children Health Care, Wuxi Maternal and Child Health Hospital, No.48 Huaishu Alley, Wuxi, Jiangsu Province, China.
| | - Hai-tao Jia
- Beijing Genomics Institute at Shenzhen, Building No.11, Beishan Industrial Zone, Yantian District, Shenzhen, Guangdong, China.
| | - Zhong-hai Chen
- Beijing Genomics Institute at Shenzhen, Building No.11, Beishan Industrial Zone, Yantian District, Shenzhen, Guangdong, China.
| | - Jia-ping Song
- Beijing Genomics Institute at Shenzhen, Building No.11, Beishan Industrial Zone, Yantian District, Shenzhen, Guangdong, China.
| | - Yu Liang
- Beijing Genomics Institute at Shenzhen, Building No.11, Beishan Industrial Zone, Yantian District, Shenzhen, Guangdong, China.
| | - Jing-jing Pei
- Department of Children Health Care, Wuxi Maternal and Child Health Hospital, No.48 Huaishu Alley, Wuxi, Jiangsu Province, China.
| | - Zhi-jun Wu
- Department of Children Health Care, Wuxi Maternal and Child Health Hospital, No.48 Huaishu Alley, Wuxi, Jiangsu Province, China.
| | - Jing Wang
- Department of Children Health Care, Suqian Maternal and Child Health Hospital, No. 9 Ping-An Road, Suqian, Jiangsu Province, China.
| | - Ya-li Qiu
- Department of Children Health Care, Suqian Maternal and Child Health Hospital, No. 9 Ping-An Road, Suqian, Jiangsu Province, China.
| | - Gang Liu
- Beijing Genomics Institute at Shenzhen, Building No.11, Beishan Industrial Zone, Yantian District, Shenzhen, Guangdong, China.
| | - Dong-mei Sun
- Beijing Genomics Institute at Shenzhen, Building No.11, Beishan Industrial Zone, Yantian District, Shenzhen, Guangdong, China.
| | - Xin-ye Jiang
- Department of Children Health Care, Wuxi Maternal and Child Health Hospital, No.48 Huaishu Alley, Wuxi, Jiangsu Province, China.
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Blau N, Longo N. Alternative therapies to address the unmet medical needs of patients with phenylketonuria. Expert Opin Pharmacother 2015; 16:791-800. [PMID: 25660215 DOI: 10.1517/14656566.2015.1013030] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Standard therapy for phenylketonuria (PKU), the most common inherited disorder in amino acid metabolism, is an onerous phenylalanine-restricted diet. Adherence to this stringent diet regimen decreases as patients get older, and this lack of adherence is directly associated with cognitive and executive dysfunction and psychiatric issues. These factors emphasize the need for alternative pharmacological therapies to help treat patients with PKU. Sapropterin dihydrochloride is a synthetic form of tetrahydrobiopterin, the cofactor of phenylalanine hydroxylase that in pharmacological doses can stabilize and increase residual enzyme activity in some patients with PKU. About one-third of all patients with PKU respond to oral sapropterin. Phenylalanine ammonia lyase (PAL) is a prokaryotic enzyme that converts phenylalanine to ammonia and trans-cinnamic acid. Phase I and II trials have shown that injectable recombinant Anabaena variabilis PAL produced in Escherichia coli conjugated with PEG can reduce phenylalanine levels in subjects with PKU. The most frequently reported adverse events were injection-site reactions, dizziness and immune reactions. Additionally, oral administration of PAL and delivery of enzyme substitution therapies by encapsulation in erythrocytes are being investigated. Novel therapies for patients with PKU appear to be options to reduce phenylalanine levels, and may reduce the deleterious effects of this disorder.
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Affiliation(s)
- Nenad Blau
- University Children's Hospital, Division of Inborn Metabolic Diseases , Im Neuenheimer Feld 669, Heidelberg 69120 , Germany
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