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Tebieva IS, Mishakova PV, Gabisova YV, Khokhova AV, Kaloeva TG, Marakhonov AV, Shchagina OA, Polyakov AV, Ginter EK, Kutsev SI, Zinchenko RA. Genetic Landscape and Clinical Features of Hyperphenylalaninemia in North Ossetia-Alania: High Frequency of P281L and P211T Genetic Variants in the PAH Gene. Int J Mol Sci 2024; 25:4598. [PMID: 38731816 PMCID: PMC11083185 DOI: 10.3390/ijms25094598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2024] [Revised: 03/30/2024] [Accepted: 04/05/2024] [Indexed: 05/13/2024] Open
Abstract
This study, conducted in the Republic of North Ossetia-Alania (RNOA), aimed to explore the genetic landscape of hyperphenylalaninemia (HPA) and phenylketonuria (PKU) in the Ossetian population using data from newborn screening (NBS). Through comprehensive molecular genetic analysis of 29 patients with HPA from diverse ethnic backgrounds, two major genetic variants in the PAH gene, P281L and P211T, were identified, constituting 50% of all detected pathogenic alleles in Ossetian patients. Remarkably, these variants exhibited an exceptionally high frequency in the Ossetian population, surpassing global prevalence rates. This study unveiled a notable prevalence of mild forms of HPA (78%), underscoring the importance of genetic counseling for carriers of pathogenic variants in the PAH gene. Moreover, the findings emphasized the necessity for ongoing monitoring of patients with mild forms, as they may lack significant symptoms for diagnosis, potentially impacting offspring. Overall, this research offers valuable insights into the genetic landscape of HPA and PKU in the Ossetian population.
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Affiliation(s)
- Inna S. Tebieva
- North-Ossetian State Medical Academy, 362003 Vladikavkaz, Russia; (I.S.T.); (T.G.K.)
- Republican Children’s Clinical Hospital, 362003 Vladikavkaz, Russia; (Y.V.G.); (A.V.K.)
| | - Polina V. Mishakova
- Research Centre for Medical Genetics, 115522 Moscow, Russia; (P.V.M.); (A.V.M.); (O.A.S.); (A.V.P.); (E.K.G.); (S.I.K.)
| | - Yulia V. Gabisova
- Republican Children’s Clinical Hospital, 362003 Vladikavkaz, Russia; (Y.V.G.); (A.V.K.)
| | - Alana V. Khokhova
- Republican Children’s Clinical Hospital, 362003 Vladikavkaz, Russia; (Y.V.G.); (A.V.K.)
| | - Tamara G. Kaloeva
- North-Ossetian State Medical Academy, 362003 Vladikavkaz, Russia; (I.S.T.); (T.G.K.)
| | - Andrey V. Marakhonov
- Research Centre for Medical Genetics, 115522 Moscow, Russia; (P.V.M.); (A.V.M.); (O.A.S.); (A.V.P.); (E.K.G.); (S.I.K.)
| | - Olga A. Shchagina
- Research Centre for Medical Genetics, 115522 Moscow, Russia; (P.V.M.); (A.V.M.); (O.A.S.); (A.V.P.); (E.K.G.); (S.I.K.)
| | - Alexander V. Polyakov
- Research Centre for Medical Genetics, 115522 Moscow, Russia; (P.V.M.); (A.V.M.); (O.A.S.); (A.V.P.); (E.K.G.); (S.I.K.)
| | - Evgeny K. Ginter
- Research Centre for Medical Genetics, 115522 Moscow, Russia; (P.V.M.); (A.V.M.); (O.A.S.); (A.V.P.); (E.K.G.); (S.I.K.)
| | - Sergey I. Kutsev
- Research Centre for Medical Genetics, 115522 Moscow, Russia; (P.V.M.); (A.V.M.); (O.A.S.); (A.V.P.); (E.K.G.); (S.I.K.)
| | - Rena A. Zinchenko
- Research Centre for Medical Genetics, 115522 Moscow, Russia; (P.V.M.); (A.V.M.); (O.A.S.); (A.V.P.); (E.K.G.); (S.I.K.)
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Upadia J, Crivelly K, Noh G, Cunningham A, Cerminaro C, Li Y, Mckoin M, Chenevert M, Andersson HC. Maximal dietary responsiveness after tetrahydrobiopterin (BH4) in 19 phenylalanine hydroxylase deficiency patients: What super-responders can expect. Mol Genet Metab Rep 2024; 38:101050. [PMID: 38469087 PMCID: PMC10926188 DOI: 10.1016/j.ymgmr.2024.101050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Accepted: 01/05/2024] [Indexed: 03/13/2024] Open
Abstract
Background Inherited phenylalanine hydroxylase deficiency, also known as phenylketonuria (PKU), causes poor growth and neurologic deficits in the untreated state. After ascertainment through newborn screen and dietary phenylalanine (Phe) restriction to achieve plasma Phe in the range of 120-360 μmol/L, these disease manifestations can be prevented. Poor compliance with protein restricted diets supported by medical food is typical in later years, beginning in the late toddler and teenage years. Pharmacologic doses of oral tetrahydrobiopterin (BH4; sapropterin dihydrochloride) is effective in reducing plasma Phe in about 40-50% of PKU patients but effectiveness is highly variable. Objective To assess the maximal responsiveness to 20 mg/kg/day oral BH4 as it affects plasma Phe and dietary Phe allowance in PKU patients. Materials and methods This was a single-center, retrospective observational study, combining case reports of individual patients. We reported an outcome of 85 patients with PKU who were trialed on BH4. Phe levels and dietary records of 19 BH4 "super-responders" were analyzed. Results Overall, 63.5% of the patients (54/85) were considered BH4 responders. However, we quantitated the dietary liberalization of 19 of our responsive patients (35%), those with at least a 2-fold increase in dietary Phe and maintenance of plasma Phe in treatment range. In these "super-responders", the mean plasma Phe at baseline was 371 ± 237 μmol/L and decreased to 284 ± 273 μmol/L after 1 year on BH4. Mean dietary Phe tolerance increased significantly from 595 ± 256 to 2260 ± 1414 mg/day (p ≤0.0001), while maintaining mean plasma Phe levels within treatment range. Four patients no longer required dietary Phe restriction and could discontinue medical food. The majority of patients had at least one BH4-responsive genotype. Conclusion This cohort demonstrates the maximally achievable dietary liberalization which some PKU patients may expect with BH4 therapy. Health benefits are considered to accrue in patients with increased intact protein.
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Affiliation(s)
- Jariya Upadia
- Hayward Genetics Center, New Orleans, LA 70112, USA
- Department of Pediatrics, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Kea Crivelly
- Hayward Genetics Center, New Orleans, LA 70112, USA
- Department of Pediatrics, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Grace Noh
- Hayward Genetics Center, New Orleans, LA 70112, USA
- Department of Pediatrics, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Amy Cunningham
- Hayward Genetics Center, New Orleans, LA 70112, USA
- Department of Pediatrics, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Caroline Cerminaro
- Hayward Genetics Center, New Orleans, LA 70112, USA
- Department of Pediatrics, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Yuwen Li
- Hayward Genetics Center, New Orleans, LA 70112, USA
- Department of Pediatrics, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Meredith Mckoin
- Hayward Genetics Center, New Orleans, LA 70112, USA
- Department of Pediatrics, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Madeline Chenevert
- Hayward Genetics Center, New Orleans, LA 70112, USA
- Department of Pediatrics, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Hans C. Andersson
- Hayward Genetics Center, New Orleans, LA 70112, USA
- Department of Pediatrics, Tulane University School of Medicine, New Orleans, LA 70112, USA
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Martinez M, Harding CO, Schwank G, Thöny B. State-of-the-art 2023 on gene therapy for phenylketonuria. J Inherit Metab Dis 2024; 47:80-92. [PMID: 37401651 PMCID: PMC10764640 DOI: 10.1002/jimd.12651] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 06/13/2023] [Accepted: 06/30/2023] [Indexed: 07/05/2023]
Abstract
Phenylketonuria (PKU) or hyperphenylalaninemia is considered a paradigm for an inherited (metabolic) liver defect and is, based on murine models that replicate all human pathology, an exemplar model for experimental studies on liver gene therapy. Variants in the PAH gene that lead to hyperphenylalaninemia are never fatal (although devastating if untreated), newborn screening has been available for two generations, and dietary treatment has been considered for a long time as therapeutic and satisfactory. However, significant shortcomings of contemporary dietary treatment of PKU remain. A long list of various gene therapeutic experimental approaches using the classical model for human PKU, the homozygous enu2/2 mouse, witnesses the value of this model to develop treatment for a genetic liver defect. The list of experiments for proof of principle includes recombinant viral (AdV, AAV, and LV) and non-viral (naked DNA or LNP-mRNA) vector delivery methods, combined with gene addition, genome, gene or base editing, and gene insertion or replacement. In addition, a list of current and planned clinical trials for PKU gene therapy is included. This review summarizes, compares, and evaluates the various approaches for the sake of scientific understanding and efficacy testing that may eventually pave the way for safe and efficient human application.
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Affiliation(s)
- Michael Martinez
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR, USA
| | - Cary O. Harding
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR, USA
| | - Gerald Schwank
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Beat Thöny
- Division of Metabolism, University Children’s Hospital Zurich and Children’s Research Centre, Zurich, Switzerland
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Pasquetti D, Gazzellone A, Rossi S, Orteschi D, L’Erario FF, Concolino P, Minucci A, Dionisi-Vici C, Genuardi M, Silvestri G, Chiurazzi P. Triple Genetic Diagnosis in a Patient with Late-Onset Leukodystrophy and Mild Intellectual Disability. Int J Mol Sci 2023; 25:495. [PMID: 38203665 PMCID: PMC10778870 DOI: 10.3390/ijms25010495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 12/20/2023] [Accepted: 12/28/2023] [Indexed: 01/12/2024] Open
Abstract
We describe the complex case of a 44-year-old man with polycystic kidney disease, mild cognitive impairment, and tremors in the upper limbs. Brain MRI showed lesions compatible with leukodystrophy. The diagnostic process, which included clinical exome sequencing (CES) and chromosomal microarray analysis (CMA), revealed a triple diagnosis: autosomal dominant polycystic kidney disease (ADPKD) due to a pathogenic variant, c.2152C>T-p.(Gln718Ter), in the PKD1 gene; late-onset phenylketonuria due to the presence of two missense variants, c.842C>T-p.(Pro281Leu) and c.143T>C-p.(Leu48Ser) in the PAH gene; and a 915 Kb duplication on chromosome 15. Few patients with multiple concurrent genetic diagnoses are reported in the literature; in this ADPKD patient, genome-wide analysis allowed for the diagnosis of adult-onset phenylketonuria (which would have otherwise gone unnoticed) and a 15q11.2 duplication responsible for cognitive and behavioral impairment with incomplete penetrance. This case underlines the importance of clinical genetics for interpreting complex results obtained by genome-wide techniques, and for diagnosing concurrent late-onset monogenic conditions.
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Affiliation(s)
- Domizia Pasquetti
- Section of Genomic Medicine, Department of Life Sciences and Public Health, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
- Medical Genetics Unit, Fondazione Policlinico Universitario “A. Gemelli” IRCCS, 00168 Rome, Italy
| | - Annalisa Gazzellone
- Section of Genomic Medicine, Department of Life Sciences and Public Health, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
- Medical Genetics Unit, Fondazione Policlinico Universitario “A. Gemelli” IRCCS, 00168 Rome, Italy
| | - Salvatore Rossi
- Department of Neurosciences, Faculty of Medicine and Surgery, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
- Neurology Unit, Fondazione Policlinico Universitario “A. Gemelli” IRCCS, 00168 Rome, Italy
| | - Daniela Orteschi
- Section of Genomic Medicine, Department of Life Sciences and Public Health, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
- Medical Genetics Unit, Fondazione Policlinico Universitario “A. Gemelli” IRCCS, 00168 Rome, Italy
| | - Federica Francesca L’Erario
- Section of Genomic Medicine, Department of Life Sciences and Public Health, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
- Medical Genetics Unit, Fondazione Policlinico Universitario “A. Gemelli” IRCCS, 00168 Rome, Italy
| | - Paola Concolino
- Departmental Unit of Molecular and Genomic Diagnostics, Fondazione Policlinico Universitario “A. Gemelli” IRCCS, 00168 Rome, Italy
| | - Angelo Minucci
- Departmental Unit of Molecular and Genomic Diagnostics, Fondazione Policlinico Universitario “A. Gemelli” IRCCS, 00168 Rome, Italy
| | - Carlo Dionisi-Vici
- Division of Metabolic Diseases, Bambino Gesù Children’s Hospital IRCCS, 00165 Rome, Italy
| | - Maurizio Genuardi
- Section of Genomic Medicine, Department of Life Sciences and Public Health, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
- Medical Genetics Unit, Fondazione Policlinico Universitario “A. Gemelli” IRCCS, 00168 Rome, Italy
| | - Gabriella Silvestri
- Department of Neurosciences, Faculty of Medicine and Surgery, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
- Neurology Unit, Fondazione Policlinico Universitario “A. Gemelli” IRCCS, 00168 Rome, Italy
| | - Pietro Chiurazzi
- Section of Genomic Medicine, Department of Life Sciences and Public Health, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
- Medical Genetics Unit, Fondazione Policlinico Universitario “A. Gemelli” IRCCS, 00168 Rome, Italy
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Sundstrom R, Wetherill L, Sapp K, McPheron M, Lah M. Relationship satisfaction in adults with phenylketonuria is positively associated with following recommended treatment, having a partner involved in management, and maintaining good health. J Community Genet 2023; 14:627-638. [PMID: 37798460 PMCID: PMC10725410 DOI: 10.1007/s12687-023-00667-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Accepted: 08/29/2023] [Indexed: 10/07/2023] Open
Abstract
RATIONALE Phenylketonuria (PKU) is a metabolic condition that requires treatment for life. There is increasing evidence that chronic illnesses put strain on relationships and marriages. However, no studies have examined the unique factors that metabolic conditions have on affected individuals and their relationship satisfaction. We surveyed a population of adult patients with PKU and assessed how management, treatment, and lifestyle factors impact their relationship satisfaction. PURPOSE The purpose of our study was to explore whether factors such as involvement of partner in PKU management, impact of challenges unique to PKU (e.g., diet, family planning, mood disturbances), and PKU treatment types were associated with the degree of relationship satisfaction. METHOD We surveyed adult patients with PKU (n = 82) who were either currently in or had previously been in a long-term relationship. We developed a 78-question survey that included unique questions regarding lifestyle, treatment, and management of their PKU in addition to a validated Relationship Assessment Score. Questions included single choice, multiple choice, and 3 open-ended questions. RESULTS We found that higher relationship satisfaction was associated with increased partner involvement, increased health, and adherence to recommended PKU treatments. Participants utilizing both diet and pharmaceutical treatment had the highest relationship satisfaction. Finally, participants who reported that their PKU did not contribute to the ending of a previous relationship reported higher relationship satisfaction scores. CONCLUSION This study suggests that involvement of partners in the management and treatment of a chronic illness and adherence to recommended treatments can significantly improve relationship satisfaction.
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Affiliation(s)
- Rachel Sundstrom
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, 975 W. Walnut, IB 130, Indianapolis, IN, 46202, USA
- Froedtert & The Medical College of Wisconsin, 9200 W. Wisconsin Ave., Milwaukee, WI, 53226, USA
| | - Leah Wetherill
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, 975 W. Walnut, IB 130, Indianapolis, IN, 46202, USA
| | - Katie Sapp
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, 975 W. Walnut, IB 130, Indianapolis, IN, 46202, USA
| | - Molly McPheron
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, 975 W. Walnut, IB 130, Indianapolis, IN, 46202, USA
| | - Melissa Lah
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, 975 W. Walnut, IB 130, Indianapolis, IN, 46202, USA.
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Tendi EA, Morello G, Guarnaccia M, La Cognata V, Petralia S, Messina MA, Meli C, Fiumara A, Ruggieri M, Cavallaro S. Detection of Single-Nucleotide and Copy Number Defects Underlying Hyperphenylalaninemia by Next-Generation Sequencing. Biomedicines 2023; 11:1899. [PMID: 37509538 PMCID: PMC10377317 DOI: 10.3390/biomedicines11071899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 06/27/2023] [Accepted: 06/29/2023] [Indexed: 07/30/2023] Open
Abstract
Hyperphenylalaninemia (HPA) is the most common inherited amino acid metabolism disorder characterized by serious clinical manifestations, including irreversible brain damage, intellectual deficiency and epilepsy. Due to its extensive genic and allelic heterogeneity, next-generation sequencing (NGS) technology may help to identify the molecular basis of this genetic disease. Herein, we describe the development and validation of a targeted NGS (tNGS) approach for the simultaneous detection of single-nucleotide changes and copy number variations (CNVs) in genes associated with HPA (PAH, GCH1, PTS, QDPR, PCBD1, DNAJC12) or useful for its differential diagnosis (SPR). Our tNGS approach offers the possibility to detail, with a high accuracy and in a single workflow, the combined effect of a broader spectrum of genomic variants in a comprehensive view, providing a significant step forward in the development of optimized patient care and management.
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Affiliation(s)
- Elisabetta Anna Tendi
- Biomedical Sciences Department, Institute for Biomedical Research and Innovation, National Research Council, Via Paolo Gaifami 18, 95026 Catania, Italy
| | - Giovanna Morello
- Biomedical Sciences Department, Institute for Biomedical Research and Innovation, National Research Council, Via Paolo Gaifami 18, 95026 Catania, Italy
| | - Maria Guarnaccia
- Biomedical Sciences Department, Institute for Biomedical Research and Innovation, National Research Council, Via Paolo Gaifami 18, 95026 Catania, Italy
| | - Valentina La Cognata
- Biomedical Sciences Department, Institute for Biomedical Research and Innovation, National Research Council, Via Paolo Gaifami 18, 95026 Catania, Italy
| | - Salvatore Petralia
- Department of Drug and Health Sciences, University of Catania, 95125 Catania, Italy
| | - Maria Anna Messina
- Regional Reference Center for the Treatment and Control of Congenital Metabolic Diseases of Childhood, Department of Clinical and Experimental Medicine, University Hospital Policlinico "Rodolico-San Marco", 95123 Catania, Italy
| | - Concetta Meli
- Regional Reference Center for the Treatment and Control of Congenital Metabolic Diseases of Childhood, Department of Clinical and Experimental Medicine, University Hospital Policlinico "Rodolico-San Marco", 95123 Catania, Italy
| | - Agata Fiumara
- Regional Reference Center for the Treatment and Control of Congenital Metabolic Diseases of Childhood, Department of Clinical and Experimental Medicine, University Hospital Policlinico "Rodolico-San Marco", 95123 Catania, Italy
| | - Martino Ruggieri
- Unit of Rare Diseases of the Nervous System in Childhood, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University Hospital Policlinico "Rodolico-San Marco", 95123 Catania, Italy
| | - Sebastiano Cavallaro
- Biomedical Sciences Department, Institute for Biomedical Research and Innovation, National Research Council, Via Paolo Gaifami 18, 95026 Catania, Italy
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Zuñiga Vinueza AM. Recent Advances in Phenylketonuria: A Review. Cureus 2023; 15:e40459. [PMID: 37456395 PMCID: PMC10349532 DOI: 10.7759/cureus.40459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/15/2023] [Indexed: 07/18/2023] Open
Abstract
This article highlights the significance of inborn errors of metabolism and focuses specifically on phenylketonuria (PKU), a well-known inheritance disorder caused by the deficiency or absence of phenylalanine hydroxylase (PAH). This review discusses associated mutations in the PAH gene and their impact on phenylalanine metabolism. A total of 40 articles were analyzed between 2019 and 2023, covering diagnostic innovations, advancements in treatment and management strategies, and the long-term implications of PKU. This study emphasizes the importance of early diagnosis and highlights the ongoing need for advancements in screening methods and treatment approaches to optimize patient outcomes in PKU patients. This review provides valuable insights for healthcare professionals involved in the care of children with PKU and contributes to the enhancement of clinical practice in this field.
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Xie K, Zeng B, Zhang L, Chen S, Zou Y, Yuan H, Huang S, Wang F, Lu Q, Liu Y, Yang B. Mutation spectrum of PTS gene in patients with tetrahydrobiopterin deficiency from jiangxi province. Front Genet 2022; 13:1077729. [PMID: 36583021 PMCID: PMC9792861 DOI: 10.3389/fgene.2022.1077729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Accepted: 11/29/2022] [Indexed: 12/15/2022] Open
Abstract
Background: Hyperphenylalaninemia (HPA) is the most common inborn error in amino acid metabolism. It can be primarily classified into phenylalanine hydroxylase (PAH) deficiency and tetrahydrobiopterin (BH4) deficiency. BH4 deficiency (BH4D) is caused by genetic defects in enzymes involved in the biosynthesis and regeneration of BH4. 6-pyruvoyl-tetrahydropterin synthase (PTPS/PTS), which is encoded by the PTS gene, participates in the biosynthesis of BH4. PTPS deficiency (PTPSD) is the major cause of BH4D. In this study, we investigated that the prevalence of BH4D in Jiangxi province was approximately 12.5 per 1,000,000 live births (69/5,541,627). Furthermore, the frequency of BH4D was estimated to be 28.8% (69/240) in the HPA population of Jiangxi. In this study, we aimed to characterize the mutational spectrum of the PTS gene in patients with PTPSD from Jiangxi province. Method: Newborn screening data of Jiangxi province from 1997 to 2021 were analyzed and 53 families with PTPSD were enrolled for the analysis of the PTS gene variants by Sanger sequencing. Results: 106 variants were identified in 106 alleles of 53 patients with PTPSD, including 13 types of variants reported previously, and two novel variants (c.164-36A>G and c.146_147insTG). The predominant variant was c.259C>T (47.2%), followed by c.84-291A>G (19.8%), c.155A>G (8.5%), c.286G>A (6.6%) and c.379C>T (4.7%). Conclusion: The results of this study can not only provide guidance for the molecular diagnosis and genetic counseling in cases of PTPS deficiency but also enrich the PTS mutation database.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Qing Lu
- *Correspondence: Qing Lu, ; Yanqiu Liu, ; Bicheng Yang,
| | - Yanqiu Liu
- *Correspondence: Qing Lu, ; Yanqiu Liu, ; Bicheng Yang,
| | - Bicheng Yang
- *Correspondence: Qing Lu, ; Yanqiu Liu, ; Bicheng Yang,
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Khaghani F, Eshraghi P, Hamzehloei T. Tetrahydrobiopterin responsiveness in Phenylalanine hydroxylase deficient patients from North-east of Iran: Genotype-phenotype correlation, identification of a novel mutation and 7 new responsive genotypes. Eur J Med Genet 2022; 65:104536. [PMID: 35690318 DOI: 10.1016/j.ejmg.2022.104536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 04/03/2022] [Accepted: 06/05/2022] [Indexed: 11/03/2022]
Abstract
Phenylalanine hydroxylase enzyme defects result in a hereditary metabolic disorder called phenylketonuria. Sapropterin (tetrahydrobiopterin) is one of the treatment strategies for this disorder. Even though a correlation between genotype and BH4 responsiveness was established by earlier studies, a subset of mutations often presented inconsistent responses and/or phenotypes. Different genetic background is one of the potential reasons for this fact. In this study, the genotype of a total of 34 PAH deficient patients from Khorasan-Razavi providence in the north-east of Iran was obtained. Among this patients, 21 individuals took the 24 h and 48 h BH4 loading test and if the result was positive, their Phenylalanine tolerance was assessed. It is the first study of its type in patients from Iran to evaluate genotype role in predicting the most probable responsive individuals. The known pathogenic variant p.R169P and the novel variant p. Leu72_Asp75delinsTyr were first classified as responsive.Seven genotypes were reported as responsive for the first time. All patients carrying at least one pathogenic variant, which was previously reported as BH4 responsive, respond to BH4. Three patients with p.L48S, p.R261Q and p.A309V pathogenic variants were exceptions. There was no certain statistical correlation between genotype and response. Genotype and phenotype were significantly correlated and majority of patients with mild phenotype carried at least one non-null pathogenic variant. In Khorasan-Razavi province of Iran, patients with at least one non-null mutation are most probable to demonstrate mild phenotype and respond to BH4 phenotype.
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Affiliation(s)
- Faeze Khaghani
- Department of Medical Genetics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran; Medical Genetics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Peyman Eshraghi
- Department of Pediatric and Endocrinology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Tayebeh Hamzehloei
- Medical Genetics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran; Metabolic Syndrome Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
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Lin C, Li Y, Zhang E, Feillet F, Zhang S, Blau N. Importance of the long non-coding RNA (lncRNA) transcript HULC for the regulation of phenylalanine hydroxylase and treatment of phenylketonuria. Mol Genet Metab 2022; 135:171-178. [PMID: 35101330 DOI: 10.1016/j.ymgme.2022.01.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 01/18/2022] [Accepted: 01/18/2022] [Indexed: 12/12/2022]
Abstract
More than 1280 variants in the phenylalanine hydroxylase (PAH) gene are responsible for a broad spectrum of phenylketonuria (PKU) phenotypes. While the genotype-phenotype correlation is reaching 88%, for some inconsistent phenotypes with the same genotype additional factors like tetrahydrobiopterin (BH4), the PAH co-chaperone DNAJC12, phosphorylation of the PAH residues or epigenetic factors may play an important role. Very recently an additional player, the long non-coding RNA (lncRNA) transcript HULC, was described to regulate PAH activity and enhance residual enzyme activity of some PAH variants (e.g., the most common p.R408W) by using HULC mimics. In this review we present an overview of the lncRNA function and in particular the interplay of the HUCL transcript with the PAH and discuss potential applications for the future treatment of some PKU patients.
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Affiliation(s)
- Chunru Lin
- Department of Molecular and Cellular Oncology, Division of Basic Science Research, The University of Texas, MD Anderson Cancer Center, Houston, TX, United States of America
| | - Yajuan Li
- Department of Molecular and Cellular Oncology, Division of Basic Science Research, The University of Texas, MD Anderson Cancer Center, Houston, TX, United States of America
| | - Eric Zhang
- Department of Experimental Therapeutics, The University of Texas, MD Anderson Cancer Center, Houston, TX, United States of America
| | - François Feillet
- INSERM, U1256, NGERE - Nutrition, Genetics, and Environmental Risk Exposure, University of Lorraine, Nancy, France; Pediatric Department Reference Center for Inborn Errors of Metabolism Children University Hospital Nancy, Nancy, France
| | - Shuxing Zhang
- Department of Experimental Therapeutics, The University of Texas, MD Anderson Cancer Center, Houston, TX, United States of America
| | - Nenad Blau
- Division of Metabolism, University Children's Hospital Zürich, Zurich, Switzerland.
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11
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Wiedemann A, Lin C, Oussalah A, Namour B, Jeannesson É, Guéant JL, Feillet F. [A long non-coding RNA regulates the activity of phenylalanine hydroxylase, the key enzyme of phenylketonuria]. Med Sci (Paris) 2022; 38:12-14. [PMID: 35060876 DOI: 10.1051/medsci/2021237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Arnaud Wiedemann
- Centre de référence des maladies métaboliques, Service de pédiatrie, CHU Nancy - Inserm U1256, Nutrition-génétique et exposition aux risques environnementaux (NGERE), 9 avenue de la forêt de Haye, CS 50184, 54505 Vandoeuvre-les-Nancy, France
| | - Chunru Lin
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, États-Unis
| | - Abderrahim Oussalah
- Inserm U1256, Nutrition-génétique et exposition aux risques environnementaux (NGERE), 9 avenue de la forêt de Haye, CS 50184, 54505 Vandoeuvre-les-Nancy, France - Laboratoire de biochimie et de biologie moléculaire, CHU Nancy
| | - Bernard Namour
- Inserm U1256, Nutrition-génétique et exposition aux risques environnementaux (NGERE), 9 avenue de la forêt de Haye, CS 50184, 54505 Vandoeuvre-les-Nancy, France - Laboratoire de biochimie et de biologie moléculaire, CHU Nancy
| | - Élise Jeannesson
- Inserm U1256, Nutrition-génétique et exposition aux risques environnementaux (NGERE), 9 avenue de la forêt de Haye, CS 50184, 54505 Vandoeuvre-les-Nancy, France - Laboratoire de biochimie et de biologie moléculaire, CHU Nancy
| | - Jean-Louis Guéant
- Inserm U1256, Nutrition-génétique et exposition aux risques environnementaux (NGERE), 9 avenue de la forêt de Haye, CS 50184, 54505 Vandoeuvre-les-Nancy, France - Laboratoire de biochimie et de biologie moléculaire, CHU Nancy
| | - François Feillet
- Centre de référence des maladies métaboliques, Service de pédiatrie, CHU Nancy - Inserm U1256, Nutrition-génétique et exposition aux risques environnementaux (NGERE), 9 avenue de la forêt de Haye, CS 50184, 54505 Vandoeuvre-les-Nancy, France
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12
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Burlina A, Biasucci G, Carbone MT, Cazzorla C, Paci S, Pochiero F, Spada M, Tummolo A, Zuvadelli J, Leuzzi V. Italian national consensus statement on management and pharmacological treatment of phenylketonuria. Orphanet J Rare Dis 2021; 16:476. [PMID: 34784942 PMCID: PMC8594187 DOI: 10.1186/s13023-021-02086-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 10/13/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Phenylketonuria (PKU) is a rare inherited metabolic disorder caused by defects in the phenylalanine-hydroxylase gene (PAH), the enzyme catalyzing the conversion of phenylalanine to tyrosine. PAH impairment causes phenylalanine accumulation in the blood and brain, with a broad spectrum of pathophysiological and neurological consequences for patients. Prevalence of disease varies, with peaks in some regions and countries, including Italy. A recent expert survey described the real-life of clinical practice for PKU in Italy, revealing inhomogeneities in disease management, particularly concerning approach to pharmacotherapy with sapropterin hydrochloride, analogous of the natural PAH co-factor, allowing disease control in a subset of patients. Therefore, the purpose of this paper is to continue the work initiated with the expert survey paper, to provide national guidances aiming to harmonize and optimize patient care at a national level. PARTICIPANTS The Consensus Group, convened by 10 Steering Committee members, consisted of a multidisciplinary crowd of 46 experts in the management of PKU in Italy. CONSENSUS PROCESS The Steering Committee met in a series of virtual meeting in order to discuss on clinical focuses to be developed and analyzed in guidance statements, on the basis of expert practice based evidence, large systematic literature review previously performed in the expert survey paper, and evidence based consensus published. Statements were re-discussed and refined during consensus conferences in the widest audience of experts, and finally submitted to the whole consensus group for a modified-Delphi voting. RESULTS Seventy three statements, divided in two main clinical areas, PKU management and Pharmacotherapy, achieved large consensus in a multidisciplinary group of expert in different aspects of disease. Importantly, these statements involve guidances for the use of sapropterin dihydrochloride, still not sufficiently implemented in Italy, and a set of good practice to approach the use of novel enzyme replacement treatment pegvaliase. CONCLUSIONS This evidence-based consensus provides a minimum set of guidances for disease management to be implemented in all PKU centers. Moreover, these guidances represent the first statement for sapropterin dihydrochloride use, implementation and standardization in Italy, and a guide for approaching pegvaliase treatment at a national level on a consistent basis.
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Affiliation(s)
- Alberto Burlina
- Division of Inherited Metabolic Diseases, Reference Center for Expanded Newborn Screening, DIDAS Servizi Di Diagnostica Integrata, University Hospital Padova, 35128, Padua, Italy
| | - Giacomo Biasucci
- Maternal and Child Health Department, Pediatrics and Neonatology Unit, Guglielmo da Saliceto Hospital, 29121, Piacenza, Italy.
| | - Maria Teresa Carbone
- Pediatric Division, Metabolic and Rare Diseases, Santobono Pausilipon Hospital, 80122, Naples, Italy
| | - Chiara Cazzorla
- Division of Inherited Metabolic Diseases, Reference Center for Expanded Newborn Screening, DIDAS Servizi Di Diagnostica Integrata, University Hospital Padova, 35128, Padua, Italy
| | - Sabrina Paci
- Paediatric Department, ASST Santi Paolo E Carlo, San Paolo Hospital, University of Milan, 20142, Milan, Italy
| | - Francesca Pochiero
- Metabolic and Muscular Unit, A. Meyer Children's Hospital, Florence, Italy
| | - Marco Spada
- Department of Pediatrics, Regina Margherita Children's Hospital, University of Torino, 10126, Turin, Italy
| | - Albina Tummolo
- Metabolic Diseases Department, Clinical Genetics and Diabetology, Giovanni XXIII Children's Hospital, 70126, Bari, Italy
| | - Juri Zuvadelli
- Paediatric Department, ASST Santi Paolo E Carlo, San Paolo Hospital, University of Milan, 20142, Milan, Italy
| | - Vincenzo Leuzzi
- Department of Human Neuroscience, Unit of Child Neurology and Psychiatry, University La Sapienza, 00185, Rome, Italy
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13
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A capillary electrophoresis-based variant hotspot genotyping method for rapid and reliable analysis of the phenylalanine hydroxylase gene in the Chinese Han population. Clin Chim Acta 2021; 523:267-272. [PMID: 34653385 DOI: 10.1016/j.cca.2021.10.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 10/09/2021] [Accepted: 10/09/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND AND AIMS Hyperphenylalaninemia (HPA) is a common autosomal recessive disorder of phenylalanine metabolism, mainly caused by the deficiency of phenylalanine hydroxylase gene (PAH). A simple, fast, and accurate assay to achieve early diagnosis for children with HPA is required. MATERIALS AND METHODS In the present study, we established a SNaPshot-based assay that allows the simultaneous genotyping of 96 hotspot variants in the PAH gene. First, 18 Chinese HPA patients were analyzed by next generation sequencing (NGS) and SNaPshot in parallel. Then, the SNaPshot assay was performed to analyze the mutational spectrum of the PAH in 4,276 individuals in Eastern China. RESULTS A total of 36 variants in the PAH gene were successfully identified by NGS, while the SNaPshot assay identified 34 PAH variants in these patients. Thus, the SNaPshot assay achieved the sensitivity and specificity of 91.6% and 100.0%, respectively. Furthermore, the carrier rate was approximately 1 in 58 (1.73%) in 4,276 individuals, and c.728G > A was the most common variant. CONCLUSION In summary, SNaPshot can accurately and rapidly detect PAH gene variants at a comparable performance and lower cost as compared with NGS. Our results suggest that SNaPshot may serve as a promising approach for a routine genetic test in clinical practice.
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14
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Makukh HV, Chorna LB, Tyrkus MY, Akopyan HR, Shuvarska VI, Malakhova AY, Poliakova YO. Analysis of the PAH Gene Mutations in the Ukrainian Population: A Report from the West Ukrainian Region. CYTOL GENET+ 2021. [DOI: 10.3103/s0095452721050066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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15
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Aslan T, Yenenler-Kutlu A, Gerlevik U, Aktuğlu Zeybek AÇ, Kıykım E, Sezerman OU, Birgul Iyison N. Identifying and elucidating the roles of Y198N and Y204F mutations in the PAH enzyme through molecular dynamic simulations. J Biomol Struct Dyn 2021; 40:9018-9029. [PMID: 33970801 DOI: 10.1080/07391102.2021.1921619] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Phenylketonuria is an autosomal recessive disorder caused by mutations in the phenylalanine hydroxylase gene. In phenylketonuria causes various symptoms including severe mental retardation. PAH gene of a classical Phenylketonuria patient was sequenced, and two novel heterozygous mutations, p.Y198N and p.Y204F, were found. This study aimed to reveal the impacts of these variants on the structural stability of the PAH enzyme. In-silico analyses using prediction tools and molecular dynamics simulations were performed. Mutations were introduced to the wild type catalytic monomer and full length tetramer crystal structures. Variant pathogenicity analyses predicted p.Y198N to be damaging, and p.Y204F to be benign by some prediction tools and damaging by others. Simulations suggested p.Y198N mutation cause significant fluctuations in the spatial organization of two catalytic residues in the temperature accelerated MD simulations with the monomer and increased root-mean-square deviations in the tetramer structure. p.Y204F causes noticeable changes in the spatial positioning of T278 suggesting a possible segregation from the catalytic site in temperature accelerated MD simulations with the monomer. This mutation also leads to increased root-mean-square fluctuations in the regulatory domain which may lead to conformational change resulting in inhibition of dimerization and enzyme activation. Our study reports two novel mutations in the PAH gene and gives insight to their effects on the PAH activity. MD simulations did not yield conclusive results that explains the phenotype but gave plausible insight to possible effects which should be investigated further with in-silico and in-vitro studies to assess the roles of these mutations in etiology of PKU. Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Tolga Aslan
- Faculty of Arts and Sciences, Department of Molecular Biology and Genetics, Bogazici University, Istanbul, Turkey
| | - Aslı Yenenler-Kutlu
- Department of Biostatistics and Medical Informatics, School of Medicine, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey.,Faculty of Science and Literature, Department of Molecular Biology & Genetics, Istinye University, Istanbul, Turkey
| | - Umut Gerlevik
- Department of Biostatistics and Medical Informatics, School of Medicine, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey
| | - Ayşe Çiğdem Aktuğlu Zeybek
- Cerrahpasa Faculty of Medicine, Divisions of Nutrition and Metabolism, Department of Pediatrics, Istanbul University, İstanbul, Turkey
| | - Ertuğrul Kıykım
- Cerrahpasa Faculty of Medicine, Divisions of Nutrition and Metabolism, Department of Pediatrics, Istanbul University, İstanbul, Turkey
| | - Osman Uğur Sezerman
- Department of Biostatistics and Medical Informatics, School of Medicine, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey
| | - Necla Birgul Iyison
- Faculty of Arts and Sciences, Department of Molecular Biology and Genetics, Bogazici University, Istanbul, Turkey
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16
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Gundorova P, Kuznetcova IA, Baydakova GV, Stepanova AA, Itkis YS, Kakaulina VS, Alferova IP, Lyazina LV, Andreeva LP, Kanivets I, Zakharova EY, Kutsev SI, Polyakov AV. BH4-deficient hyperphenylalaninemia in Russia. PLoS One 2021; 16:e0249608. [PMID: 33822819 PMCID: PMC8023510 DOI: 10.1371/journal.pone.0249608] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 03/22/2021] [Indexed: 02/07/2023] Open
Abstract
A timely detection of patients with tetrahydrobiopterin (BH4) -deficient types of hyperphenylalaninemia (HPABH4) is important for assignment of correct therapy, allowing to avoid complications. Often HPABH4 patients receive the same therapy as phenylalanine hydroxylase (PAH) -deficiency (phenylketonuria) patients—dietary treatment—and do not receive substitutive BH4 therapy until the diagnosis is confirmed by molecular genetic means. In this study, we present a cohort of 30 Russian patients with HPABH4 with detected variants in genes causing different types of HPA. Family diagnostics and biochemical urinary pterin spectrum analyses were carried out. HPABH4A is shown to be the prevalent type, 83.3% of all HPABH4 cases. The mutation spectrum for the PTS gene was defined, the most common variants in Russia were p.Thr106Met—32%, p.Asn72Lys—20%, p.Arg9His—8%, p.Ser32Gly—6%. We also detected 7 novel PTS variants and 3 novel QDPR variants. HPABH4 prevalence was estimated to be 0.5–0.9% of all HPA cases in Russia, which is significantly lower than in European countries on average, China, and Saudi Arabia. The results of this research show the necessity of introducing differential diagnostics for HPABH4 into neonatal screening practice.
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Affiliation(s)
| | | | | | | | | | - Victoria S. Kakaulina
- Federal State Budgetary Institution of Medical Department of Moscow “Morozov Children’s City Clinical Hospital of Medical Department of Moscow”, Moscow, Russia
| | - Irina P. Alferova
- Municipal Autonomous Health Care Institution of the Order of the Red Banner of Labor “Clinical Hospital № 1”, Chelyabinsk, Russia
| | - Lidya V. Lyazina
- Saint Petersburg State Public Health Institution "Medical Genetic Diagnostic Center”, Saint Petersburg, Russia
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17
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Tao Y, Han D, Shen H, Li X. Spectrum of PAH gene mutations and genotype-phenotype correlation in patients with phenylalanine hydroxylase deficiency from Shanxi province. Brain Dev 2021; 43:220-229. [PMID: 32893076 DOI: 10.1016/j.braindev.2020.08.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 08/04/2020] [Accepted: 08/18/2020] [Indexed: 01/12/2023]
Abstract
BACKGROUND Phenylalanine hydroxylase deficiency (PAHD) is an autosomal recessive inborn error that affects phenylalanine (Phe) metabolism. It has a complex phenotype with many variants and genotypes among different populations. Shanxi province is a high-prevalence area of PAHD in China. METHODS In this study, eighty-nine PAHD patients were subjected to genetic testing using Sanger sequencing, followed by multiplex ligation-dependent probe amplification analysis (MLPA). Allelic and genotypic phenotype values (APV and GPV, respectively) were used for genotype-based phenotypic prediction. RESULTS Fifty-one types of variants, including three novel forms, were identified. The predominant variant was p.R243Q (22.09%), followed by p.R53H (10.47%), p.EX6-96A > G (9.30%), p.V399V (5.23%) and p.R413P (3.49%). Notably, mild hyperphenylalaninemia (MHP) has a high prevalence in this region (up to 45.76%), and the variant p.R53H was solely observed in patients of MHP. According to the genotype-phenotype prediction, the APV/GPV system was well correlated with the metabolic phenotype of most PAHD patients. CONCLUSION We have systematically constructed the mutational and phenotypic spectrum of PAH in Shanxi province. Hence, this study will help to further understand the genotype-phenotype associations in PAHD patients, and it may offer more reliable genetic counseling and management.
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Affiliation(s)
- Yilun Tao
- Medical Genetic Center, Changzhi Maternal and Child Health Care Hospital, 38 Weiyuanmen Road, Changzhi, Shanxi 046000, China
| | - Dong Han
- Medical Genetic Center, Changzhi Maternal and Child Health Care Hospital, 38 Weiyuanmen Road, Changzhi, Shanxi 046000, China
| | - Huiyi Shen
- Medical Genetic Center, Changzhi Maternal and Child Health Care Hospital, 38 Weiyuanmen Road, Changzhi, Shanxi 046000, China
| | - Xiaoze Li
- Medical Genetic Center, Changzhi Maternal and Child Health Care Hospital, 38 Weiyuanmen Road, Changzhi, Shanxi 046000, China.
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18
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Sobering AK, Li D, Beighley JS, Carey JC, Donald T, Elsea SH, Figueroa KP, Gerdts J, Hamlet A, Mirzaa GM, Nelson B, Pulst SM, Smith JL, Tassone F, Toriello HV, Walker RH, Yearwood KR, Bhoj EJ. Experiences with offering pro bono medical genetics services in the West Indies: Benefits to patients, physicians, and the community. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2020; 184:1030-1041. [PMID: 33274544 DOI: 10.1002/ajmg.c.31871] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 11/21/2020] [Accepted: 11/25/2020] [Indexed: 12/16/2022]
Abstract
We describe our experiences with organizing pro bono medical genetics and neurology outreach programs on several different resource-limited islands in the West Indies. Due to geographic isolation, small population sizes, and socioeconomic disparities, most Caribbean islands lack medical services for managing, diagnosing, and counseling individuals with genetic disorders. From 2015 to 2019, we organized 2-3 clinics per year on various islands in the Caribbean. We also organized a week-long clinic to provide evaluations for children suspected of having autism spectrum disorder. Consultations for over 100 different individuals with suspected genetic disorders were performed in clinics or during home visits following referral by locally registered physicians. When possible, follow-up visits were attempted. When available and appropriate, clinical samples were shipped to collaborating laboratories for molecular analysis. Laboratory tests included karyotyping, cytogenomic microarray analysis, exome sequencing, triplet repeat expansion testing, blood amino acid level determination, biochemical assaying, and metabolomic profiling. We believe that significant contributions to healthcare by genetics professionals can be made even if availability is limited. Visiting geneticists may help by providing continuing medical education seminars. Clinical teaching rounds help to inform local physicians regarding the management of genetic disorders with the aim of generating awareness of genetic conditions. Even when only periodically available, a visiting geneticist may benefit affected individuals, their families, their local physicians, and the community at large.
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Affiliation(s)
- Andrew K Sobering
- Department of Biochemistry, St. George's University School of Medicine, St. George's, Grenada.,Windward Islands Research and Education Foundation, True Blue, St. George's, Grenada
| | - Dong Li
- Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Jennifer S Beighley
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, Washington, USA
| | - John C Carey
- Department of Pediatrics, University of Utah Health, Salt Lake City, Utah, USA
| | - Tyhiesia Donald
- Grenada General Hospital, Pediatrics Ward, St. George's, Grenada.,Clinical Teaching Unit, St. George's University School of Medicine, St. George's, Grenada
| | - Sarah H Elsea
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Karla P Figueroa
- Department of Neurology, University of Utah, Salt Lake City, Utah, USA
| | - Jennifer Gerdts
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, Washington, USA
| | - Andre Hamlet
- Grenada General Hospital, Pediatrics Ward, St. George's, Grenada.,Clinical Teaching Unit, St. George's University School of Medicine, St. George's, Grenada
| | - Ghayda M Mirzaa
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, USA.,Department of Pediatrics, University of Washington, Seattle, Washington, USA.,Brotman Baty Institute for Precision Medicine, Seattle, Washington, USA
| | - Beverly Nelson
- Clinical Teaching Unit, St. George's University School of Medicine, St. George's, Grenada
| | - Stefan M Pulst
- Department of Neurology, University of Utah, Salt Lake City, Utah, USA
| | - Janice L Smith
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Flora Tassone
- Department of Biochemistry and Molecular Medicine, University of California Davis, School of Medicine, Sacramento, California, USA.,MIND Institute, University of California Davis Medical Center, Sacramento, California, USA
| | - Helga V Toriello
- Department of Pediatrics/Human Development College of Human Medicine, Michigan State University, Grand Rapids, Michigan, USA
| | - Ruth H Walker
- Department of Neurology, James J. Peters Veterans Affairs Medical Center, Bronx, New York, USA.,Department of Neurology, Mount Sinai School of Medicine, New York City, New York, USA
| | | | - Elizabeth J Bhoj
- Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
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19
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Richards DY, Winn SR, Dudley S, Fedorov L, Rimann N, Thöny B, Harding CO. A novel Pah-exon1 deleted murine model of phenylalanine hydroxylase (PAH) deficiency. Mol Genet Metab 2020; 131:306-315. [PMID: 33051130 PMCID: PMC8173763 DOI: 10.1016/j.ymgme.2020.09.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 09/16/2020] [Accepted: 09/23/2020] [Indexed: 12/26/2022]
Abstract
Phenylalanine hydroxylase (PAH) deficiency, colloquially known as phenylketonuria (PKU), is among the most common inborn errors of metabolism and in the past decade has become a target for the development of novel therapeutics such as gene therapy. PAH deficient mouse models have been key to new treatment development, but all prior existing models natively express liver PAH polypeptide as inactive or partially active PAH monomers, which complicates the experimental assessment of protein expression following therapeutic gene, mRNA, protein, or cell transfer. The mutant PAH monomers are able to form hetero-tetramers with and inhibit the overall holoenzyme activity of wild type PAH monomers produced from a therapeutic vector. Preclinical therapeutic studies would benefit from a PKU model that completely lacks both PAH activity and protein expression in liver. In this study, we employed CRISPR/Cas9-mediated gene editing in fertilized mouse embryos to generate a novel mouse model that lacks exon 1 of the Pah gene. Mice that are homozygous for the Pah exon 1 deletion are viable, severely hyperphenylalaninemic, accurately replicate phenotypic features of untreated human classical PKU and lack any detectable liver PAH activity or protein. This model of classical PKU is ideal for further development of gene and cell biologics to treat PKU.
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Affiliation(s)
- Daelyn Y Richards
- Department of Medical and Molecular Genetics, Oregon Health & Science University, Portland, USA
| | - Shelley R Winn
- Department of Medical and Molecular Genetics, Oregon Health & Science University, Portland, USA
| | - Sandra Dudley
- Department of Medical and Molecular Genetics, Oregon Health & Science University, Portland, USA
| | - Lev Fedorov
- Transgenic Mouse Models Core, Oregon Health and Science University, Portland, USA
| | - Nicole Rimann
- Division of Metabolism, University Children's Hospital, Steinweissstrasse 75, Zurich CH-8032, Switzerland
| | - Beat Thöny
- Division of Metabolism, University Children's Hospital, Steinweissstrasse 75, Zurich CH-8032, Switzerland
| | - Cary O Harding
- Department of Medical and Molecular Genetics, Oregon Health & Science University, Portland, USA.
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20
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Wiedemann A, Oussalah A, Jeannesson É, Guéant JL, Feillet F. [Phenylketonuria, from diet to gene therapy]. Med Sci (Paris) 2020; 36:725-734. [PMID: 32821049 DOI: 10.1051/medsci/2020127] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The prognosis for phenylketonuria (PKU) has been improved by neonatal screening and dietary management via a low-phenylalanine diet. This treatment must be followed throughout life, which induces severe compliance problems. Drug treatment with sapropterin (or BH4) has come to help a reduced percentage of patients who respond to this drug. A subcutaneous enzyme therapy is available in the USA and has obtained European marketing authorization, but generates significant side effects, which limits its effectiveness. New therapeutic options for PKU are currently being developed, in particular gene therapy. The purpose of this article is to take stock of the pathophysiology and the various new therapeutic modalities currently in development.
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Affiliation(s)
- Arnaud Wiedemann
- Centre de référence des maladies métaboliques, Service de pédiatrie, CHRU de Nancy, 54000 Nancy, France - Inserm UMR_S 1256 (NGERE, Nutrition Génétique et Exposition aux Risques Environnementaux), Faculté de médecine de Nancy, Université de Lorraine, 54000 Nancy, France
| | - Abderrahim Oussalah
- Inserm UMR_S 1256 (NGERE, Nutrition Génétique et Exposition aux Risques Environnementaux), Faculté de médecine de Nancy, Université de Lorraine, 54000 Nancy, France - Département de médecine moléculaire, Laboratoire de biochimie et de biologie moléculaire nutrition, CHRU de Nancy, 54000 France
| | - Élise Jeannesson
- Inserm UMR_S 1256 (NGERE, Nutrition Génétique et Exposition aux Risques Environnementaux), Faculté de médecine de Nancy, Université de Lorraine, 54000 Nancy, France - Département de médecine moléculaire, Laboratoire de biochimie et de biologie moléculaire nutrition, CHRU de Nancy, 54000 France
| | - Jean-Louis Guéant
- Inserm UMR_S 1256 (NGERE, Nutrition Génétique et Exposition aux Risques Environnementaux), Faculté de médecine de Nancy, Université de Lorraine, 54000 Nancy, France - Département de médecine moléculaire, Laboratoire de biochimie et de biologie moléculaire nutrition, CHRU de Nancy, 54000 France
| | - François Feillet
- Centre de référence des maladies métaboliques, Service de pédiatrie, CHRU de Nancy, 54000 Nancy, France - Inserm UMR_S 1256 (NGERE, Nutrition Génétique et Exposition aux Risques Environnementaux), Faculté de médecine de Nancy, Université de Lorraine, 54000 Nancy, France
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21
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Lipids and phenylketonuria: Current evidences pointed the need for lipidomics studies. Arch Biochem Biophys 2020; 688:108431. [DOI: 10.1016/j.abb.2020.108431] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 05/06/2020] [Accepted: 05/20/2020] [Indexed: 02/06/2023]
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22
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Costa RD, Galera BB, Rezende BC, Venâncio AC, Galera MF. IDENTIFICATION OF MUTATIONS IN THE PAH GENE IN PKU PATIENTS IN THE STATE OF MATO GROSSO. REVISTA PAULISTA DE PEDIATRIA 2020; 38:e2018351. [PMID: 32074228 PMCID: PMC7025444 DOI: 10.1590/1984-0462/2020/38/2018351] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 04/21/2019] [Indexed: 11/21/2022]
Abstract
Objective: To identify phenylalanine hydroxylase (PAH) mutations in
patients with phenylketonuria (PKU) from the Newborn Screening Service in
Mato Grosso, Midwest Brazil. Methods: This is a cross-sectional descriptive study. The sample consisted of 19 PKU
patients diagnosed by newborn screening. Molecular analysis: DNA extraction
using the “salting-out” method. Detection of IVS10nt-11G>A, V388M, R261Q,
R261X, R252W, and R408W mutations by the restriction fragment length
polymorphism (RFLP) technique. Results: Two mutant alleles were identified in four patients (21.1%), one allele in
five patients (26.2%), and none in the remaining ten patients (52.6%). A
total of 13/38 alleles were detected, corresponding to 34.2% of the
PAH alleles present. The most prevalent variant was
V388M (13.2% of the alleles), followed by R261Q (10.1%) and IVS10nt-11G>A
(7.9%). Three variants (R261X, R252W, and R408W) were not found. The most
frequent mutation types were: missense mutation in eight alleles (18.4%) and
splicing in four alleles (10.5%). The model proposed by Guldberg to
determine a genotype/phenotype correlation was applied to four classical PKU
patients with two identified mutations. In three of them, the predicted
moderate/moderate or moderate PKU phenotype did not coincide with the actual
diagnosis. The prediction coincided with the diagnosis of one classic PKU
patient. The estimated incidence of PKU for Mato Grosso, Brazil, was
1:33,342 live births from 2003 to 2015. Conclusion: The only mutations found in the analyzed samples were the IVS10nt-11G>A,
V388M, and R261Q. The genotype/phenotype correlation only occurred in four
(5.3%) patients.
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23
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Harding CO. Prospects for Cell-Directed Curative Therapy of Phenylketonuria (PKU). MOLECULAR FRONTIERS JOURNAL 2019; 3:110-121. [PMID: 32524084 PMCID: PMC7286632 DOI: 10.1142/s2529732519400145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Phenylketonuria (PKU) due to recessively inherited phenylalanine hydroxylase (PAH) deficiency is among the most common inborn errors of metabolism. Dietary therapy begun early in infancy prevents the major manifestations of the disease but shortcomings to treatment continue to exist including lifelong commitment to a complicated and unpalatable diet, poor adherence to diet in adolescence and adulthood, and consequently a range of unsatisfactory outcomes, including neuropsychiatric disorders, frequently develop. Novel treatments that do not strictly depend upon dietary protein restriction are actively sought. This review discusses the potential for and the limitations of permanently curative cell-directed treatment of PKU, including liver-directed gene therapy and gene editing, if initiated during early infancy. A fictional but realistic vignette of a family with a new baby girl recently diagnosed with PKU is presented. What is needed to permanently cure her?
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Affiliation(s)
- Cary O Harding
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Mailstop L-103, 3181 Sam Jackson Park Rd., Portland, OR 97239, USA
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24
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Rajabi F, Rohr F, Wessel A, Martell L, Dobrowolski SF, Guldberg P, Güttler F, Levy HL. Phenylalanine hydroxylase genotype-phenotype associations in the United States: A single center study. Mol Genet Metab 2019; 128:415-421. [PMID: 31623983 DOI: 10.1016/j.ymgme.2019.09.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 09/12/2019] [Accepted: 09/13/2019] [Indexed: 11/28/2022]
Abstract
Phenylketonuria (PKU) is an autosomal recessive inborn error of metabolism caused by pathogenic variants in the phenylalanine hydroxylase gene (PAH). The correlation between genotype and phenotype can be complex and sometimes variable but often very useful for categorizing and predicting dietary tolerance and potential outcome. We reviewed medical records for 367 patients diagnosed with PKU or persistent mild hyperphenylalaninemia (MHP) between 1950 and 2015 who had PAH genotyping. In 351 we had the full PAH genotype as well as phenotypic characteristics such as phenylalanine (Phe) concentrations (at newborn screening, confirmation, and highest known), and dietary Phe tolerance. On 716 mutant chromosomes, including 14 in genotypes with only one identified variant, we identified 114 different pathogenic variants. The most frequent, p.R408W, was present in 15.4% of the alleles; other frequent variants were c.1315 + 1G > A (6.1%), p.I65T (5.7%), and p.R261Q (5.7%). Three variants, c.142 T > G (p.L48 V), c.615G > C (p.E205D), and c.1342_1345delCTCC, were novel. We used the phenotypic parameters of variants paired with null alleles (functional hemizygotes) to assign the variants as classic PKU, moderate PKU, mild PKU, MHP-gray zone, or MHP. We also included the phenotype association(s) for all of the full genotypes. In 103 patients, we also could assign sapropterin dihydrochloride responsiveness, which is a synthetic form of the tetrahydrobiopterin (BH4) PAH cofactor. This compilation from a single metabolic center provides further information on PAH variants in the United States and the correlations between genotype and phenotype.
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Affiliation(s)
- Farrah Rajabi
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, USA
| | - Frances Rohr
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, USA
| | - Ann Wessel
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, USA
| | - Leslie Martell
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, USA
| | | | - Per Guldberg
- Danish Cancer Society Research Center, Copenhagen, Denmark
| | | | - Harvey L Levy
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, USA; Department of Pediatrics, Harvard Medical School, Boston, MA, USA.
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25
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Kuznetcova I, Gundorova P, Ryzhkova O, Polyakov A. The study of the full spectrum of variants leading to hyperphenylalaninemia have revealed 10 new variants in the PAH gene. Metab Brain Dis 2019; 34:1547-1555. [PMID: 31332730 DOI: 10.1007/s11011-019-00461-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 07/08/2019] [Indexed: 12/21/2022]
Abstract
This study presents further research into the spectrum of variants in genes responsible for the development of phenylketonuria (PKU) and hyperphenylalaninemia (HPA) in patients in Russia. After a study of 25 frequent variants, 293 patients (327 chromosomes without detected variants) from among 1265 probands still had no confirmed diagnosis. A study involving methods of next generation sequencing (NGS) of PAH, PTS, GCH1, PCBD1, QDPR, SPR and DNAJC12 genes to search for point mutations and multiplex ligation-dependent probe amplification (MLPA) methods to search for gross deletions were conducted for these patients. Among 327 chromosomes without identified variants, variants in the PAH gene were found on 260 chromosomes, and variants in the PTS gene were found on 10 chromosomes. On 10 chromosomes gross deletions by the MLPA method were detected. 104 rare variants of the РАН gene, including 10 variants not previously described, and 6 variants of the PTS gene were revealed. The NGS method revealed additional РАН gene variants on 10.3% of chromosomes and PTS gene variants on 0.4%. Gross deletions of the РАН gene were revealed in 0.5% of chromosomes. Thus, the most complete understanding of the spectrum of variants leading to the development of the PKU and HPA in Russia with the use of all methods available today has been obtained. Such a detailed study of the spectrum of rare variants on the genetic material from Russia was undertaken for the first time.
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Affiliation(s)
- I Kuznetcova
- Federal State Funded Research Institution "Research Centre of Medical Genetics", Moscow, Russian Federation.
| | - P Gundorova
- Federal State Funded Research Institution "Research Centre of Medical Genetics", Moscow, Russian Federation
| | - O Ryzhkova
- Federal State Funded Research Institution "Research Centre of Medical Genetics", Moscow, Russian Federation
| | - A Polyakov
- Federal State Funded Research Institution "Research Centre of Medical Genetics", Moscow, Russian Federation
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26
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Gundorova P, Kuznetsova IA, Agladze D, Margvelashvili L, Kldiashvili E, Kvlividze O, Kutsev SI, Polyakov AV. Molecular-Genetic Study of Phenylketonuria in Patients from Georgia. RUSS J GENET+ 2019. [DOI: 10.1134/s1022795419080064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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27
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Pecimonova M, Kluckova D, Csicsay F, Reblova K, Krahulec J, Procházkova D, Skultety L, Kadasi L, Soltysova A. Structural and Functional Impact of Seven Missense Variants of Phenylalanine Hydroxylase. Genes (Basel) 2019; 10:E459. [PMID: 31208052 PMCID: PMC6628251 DOI: 10.3390/genes10060459] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Revised: 06/12/2019] [Accepted: 06/13/2019] [Indexed: 11/17/2022] Open
Abstract
The molecular genetics of well-characterized inherited diseases, such as phenylketonuria (PKU) and hyperphenylalaninemia (HPA) predominantly caused by mutations in the phenylalanine hydroxylase (PAH) gene, is often complicated by the identification of many novel variants, often with no obvious impact on the associated disorder. To date, more than 1100 PAH variants have been identified of which a substantial portion have unknown clinical significance. In this work, we study the functionality of seven yet uncharacterized PAH missense variants p.Asn167Tyr, p.Thr200Asn, p.Asp229Gly, p.Gly239Ala, p.Phe263Ser, p.Ala342Pro, and p.Ile406Met first identified in the Czech PKU/HPA patients. From all tested variants, three of them, namely p.Asn167Tyr, p.Thr200Asn, and p.Ile406Met, exerted residual enzymatic activity in vitro similar to wild type (WT) PAH, however, when expressed in HepG2 cells, their protein level reached a maximum of 72.1% ± 4.9%, 11.2% ± 4.2%, and 36.6% ± 7.3% compared to WT PAH, respectively. Remaining variants were null with no enzyme activity and decreased protein levels in HepG2 cells. The chaperone-like effect of applied BH4 precursor increased protein level significantly for p.Asn167Tyr, p.Asp229Gly, p.Ala342Pro, and p.Ile406Met. Taken together, our results of functional characterization in combination with in silico prediction suggest that while p.Asn167Tyr, p.Thr200Asn, and p.Ile406Met PAH variants have a mild impact on the protein, p.Asp229Gly, p.Gly239Ala, p.Phe263Ser, and p.Ala342Pro severely affect protein structure and function.
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Affiliation(s)
- Martina Pecimonova
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, Ilkovicova 6, 842 15 Bratislava, Slovakia.
| | - Daniela Kluckova
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, Ilkovicova 6, 842 15 Bratislava, Slovakia.
| | - Frantisek Csicsay
- Insitute of Virology, Biomedical Research Center, Slovak Academy of Sciences, Dubravska cesta 9, 845 05 Bratislava, Slovakia.
| | - Kamila Reblova
- Central European Institute of Technology, Masaryk University, 625 00 Brno, Czech Republic.
| | - Jan Krahulec
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, Ilkovicova 6, 842 15 Bratislava, Slovakia.
| | - Dagmar Procházkova
- Department of Pediatrics, Medical Faculty of Masaryk University and University Hospital Brno, Černopolní 9, 625 00 Brno, Czech Republic.
| | - Ludovit Skultety
- Insitute of Virology, Biomedical Research Center, Slovak Academy of Sciences, Dubravska cesta 9, 845 05 Bratislava, Slovakia.
| | - Ludevit Kadasi
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, Ilkovicova 6, 842 15 Bratislava, Slovakia.
- Institute for Clinical and Translational Research, Biomedical Research Center, Slovak Academy of Sciences, Dubravska cesta 9, 845 05 Bratislava, Slovakia.
| | - Andrea Soltysova
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, Ilkovicova 6, 842 15 Bratislava, Slovakia.
- Institute for Clinical and Translational Research, Biomedical Research Center, Slovak Academy of Sciences, Dubravska cesta 9, 845 05 Bratislava, Slovakia.
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28
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Muntau AC, Adams DJ, Bélanger-Quintana A, Bushueva TV, Cerone R, Chien YH, Chiesa A, Coşkun T, de Las Heras J, Feillet F, Katz R, Lagler F, Piazzon F, Rohr F, van Spronsen FJ, Vargas P, Wilcox G, Bhattacharya K. International best practice for the evaluation of responsiveness to sapropterin dihydrochloride in patients with phenylketonuria. Mol Genet Metab 2019; 127:1-11. [PMID: 31103398 DOI: 10.1016/j.ymgme.2019.04.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 03/14/2019] [Accepted: 04/13/2019] [Indexed: 12/26/2022]
Abstract
Phenylketonuria (PKU) is an inherited metabolic disease caused by phenylalanine hydroxylase (PAH) deficiency. As the resulting high blood phenylalanine (Phe) concentration can have detrimental effects on brain development and function, international guidelines recommend lifelong control of blood Phe concentration with dietary and/or medical therapy. Sapropterin dihydrochloride is a synthetic preparation of tetrahydrobiopterin (6R-BH4), the naturally occurring cofactor of PAH. It acts as a pharmacological chaperone, reducing blood Phe concentration and increasing dietary Phe tolerance in BH4-responsive patients with PAH deficiency. Protocols to establish responsiveness to sapropterin dihydrochloride vary widely. Two meetings were held with an international panel of clinical experts in PKU management to develop recommendations for sapropterin dihydrochloride response testing. At the first meeting, regional differences and similarities in testing practices were discussed based on guidelines, a literature review, outcomes of a global physician survey, and case reports. Statements developed based on the discussions were sent to all participants for consensus (>70% of participants) evaluation using a 7-level rating system, and further discussed during the second meeting. The experts recommend sapropterin dihydrochloride response testing in patients with untreated blood Phe concentrations of 360-2000 μmol/L, except in those with two null mutations. For neonates, a 24-h sapropterin dihydrochloride loading test is recommended; responsiveness is defined as a decrease in blood Phe ≥30%. For older infants, children, adolescents, and adults, a test duration of ≥48 h or a 4-week trial is recommended. The main endpoint for a 48-h to 7-day trial is a decrease in blood Phe, while improved Phe tolerance is the endpoint to be assessed during a longer trial. Longer trials may not be feasible in some locations due to lack of reimbursement for hospitalization, while a 4-week trial may not be possible due to limited access to sapropterin dihydrochloride or public health regulation. A 48-h response test should be considered in pregnant patients who cannot achieve blood Phe ≤360 μmol/L with a Phe-restricted diet. Durability of response and clinical benefits of sapropterin dihydrochloride should be assessed over the long term. Harmonization of protocols is expected to improve identification of responders and comparability of test results worldwide.
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Affiliation(s)
- Ania C Muntau
- University Children's Hospital, University Medical Center Hamburg Eppendorf, Hamburg, Germany.
| | - Darius J Adams
- Atlantic Health System, Morristown Medical Center, Morristown, NJ, USA.
| | | | - Tatiana V Bushueva
- National Medical Research Center of Children's Health of the Ministry of Health of the Russian Federation, Moscow, Russia.
| | - Roberto Cerone
- G. Gaslini Institute, University of Genova, Genova, Italy.
| | | | - Ana Chiesa
- Centro de Investigaciones Endocrinologicas "Dr Cesar Bergadá" CEDIE, CONICET, Hospital de Niños Ricardo Gutierrez, Fundacion de Endocrinologia Infantil, Buenos Aires, Argentina.
| | - Turgay Coşkun
- Hacettepe University Faculty of Medicine, Ankara, Turkey.
| | - Javier de Las Heras
- Hospital Universitario de Cruces, Biocruces Health Research Institute and University of the Basque Country UPV/EHU, Vizcaya, Spain.
| | - François Feillet
- Children's University Hospital, CHU Brabois, Vandoeuvre les Nancy, France.
| | - Rachel Katz
- Ann and Robert Lurie Children's Hospital of Chicago, Chicago, IL, USA.
| | | | - Flavia Piazzon
- Associação de Pais e Amigos dos Excepcionais de São Paulo (APAE DE SÃO PAULO), São Paulo, SP, Brazil.
| | - Fran Rohr
- Boston Children's Hospital, Boston, MA, USA.
| | - Francjan J van Spronsen
- Beatrix Children's Hospital, University Medical Center of Groningen, University of Groningen, Groningen, the Netherlands.
| | - Paula Vargas
- Hospital Materno Infantil Presidente Vargas, Porto Alegre, RS, Brazil.
| | - Gisela Wilcox
- University of Manchester & Salford Royal NHS Foundation Trust, Salford, UK.
| | - Kaustuv Bhattacharya
- Genetic Metabolic Disorders Service, University of Sydney, Children's Hospital Westmead Clinical School, Sydney, NSW, Australia.
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29
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Vieira Neto E, Laranjeira F, Quelhas D, Ribeiro I, Seabra A, Mineiro N, Carvalho LM, Lacerda L, Ribeiro MG. Genotype-phenotype correlations and BH 4 estimated responsiveness in patients with phenylketonuria from Rio de Janeiro, Southeast Brazil. Mol Genet Genomic Med 2019; 7:e610. [PMID: 30829006 PMCID: PMC6503030 DOI: 10.1002/mgg3.610] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 01/15/2019] [Accepted: 01/24/2019] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Genetic heterogeneity and compound heterozygosis give rise to a continuous spectrum of phenylalanine hydroxylase deficiency and metabolic phenotypes in phenylketonuria (PKU). The most used parameters for evaluating phenotype in PKU are pretreatment phenylalanine (Phe) levels, tolerance for dietary Phe, and Phe overloading test. Phenotype can vary from a "classic" (severe) form to mild hyperphenylalaninemia, which does not require dietary treatment. A subset of patients is responsive to treatment by the cofactor tetrahydrobiopterin (BH4 ). Genotypes of PKU patients from Rio de Janeiro, Brazil, were compared to predicted and observed phenotypes. Genotype-based estimations of responsiveness to BH4 were also conducted. METHODS Phenotype was defined by pretreatment Phe levels. A standard prediction system based on arbitrary assigned values was employed to measure genotype-phenotype concordance. Patients were also estimated as BH4 -responders according to the responsiveness previously reported for their mutations and genotypes. RESULTS A 48.3% concordance rate between genotype-predicted and observed phenotypes was found. When the predicted phenotypes included those reported at the BIOPKU database, the concordance rate reached 77%. A total of 18 genotypes from 30 patients (29.4%) were estimated as of potential or probable BH4 responsiveness. Inconsistencies were observed in genotypic combinations including the common "moderate" mutations p.R261Q, p.V388M, and p.I65T and the mild mutations p.L48S, p.R68S, and p.L249F. CONCLUSION The high discordance rate between genotype-predicted and observed metabolic phenotypes in this study seems to be due partially to the high frequency of the so-called "moderate" common mutations, p.R261Q, p.V388M, and p.I65T, which are reported to be associated to erratic or more severe than expected metabolic phenotypes. Although our results of BH4 estimated responsiveness must be regarded as tentative, it should be emphasized that genotyping and genotype-phenotype association studies are important in selecting patients to be offered a BH4 overload test, especially in low-resource settings like Brazil.
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Affiliation(s)
- Eduardo Vieira Neto
- Agência Nacional de Saúde SuplementarGerência de Monitoramento AssistencialRio de JaneiroBrazil
- Serviço de Genética MédicaInstituto de Puericultura e Pediatria Martagão GesteiraUniversidade Federal do Rio de JaneiroRio de JaneiroBrazil
| | - Francisco Laranjeira
- Centro de Genética Médica Doutor Jacinto MagalhãesUnidade de Bioquímica GenéticaPortoPortugal
| | - Dulce Quelhas
- Centro de Genética Médica Doutor Jacinto MagalhãesUnidade de Bioquímica GenéticaPortoPortugal
- Unidade Multidisciplinar de Investigação BiomédicaUniversidade do PortoPortoPortugal
| | - Isaura Ribeiro
- Centro de Genética Médica Doutor Jacinto MagalhãesUnidade de Bioquímica GenéticaPortoPortugal
- Unidade Multidisciplinar de Investigação BiomédicaUniversidade do PortoPortoPortugal
| | - Alexandre Seabra
- Centro de Genética Médica Doutor Jacinto MagalhãesUnidade de Bioquímica GenéticaPortoPortugal
- Instituto de Ciências Biomédicas Abel SalazarUniversidade do PortoPortoPortugal
| | - Nicole Mineiro
- Centro de Genética Médica Doutor Jacinto MagalhãesUnidade de Bioquímica GenéticaPortoPortugal
| | - Lilian M. Carvalho
- Serviço de MetabologiaInstituto Estadual de Diabetes e Endocrinologia Luiz CapriglioneRio de JaneiroBrazil
| | - Lúcia Lacerda
- Centro de Genética Médica Doutor Jacinto MagalhãesUnidade de Bioquímica GenéticaPortoPortugal
| | - Márcia G. Ribeiro
- Serviço de Genética MédicaInstituto de Puericultura e Pediatria Martagão GesteiraUniversidade Federal do Rio de JaneiroRio de JaneiroBrazil
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30
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Genotypes of 2579 patients with phenylketonuria reveal a high rate of BH4 non-responders in Russia. PLoS One 2019; 14:e0211048. [PMID: 30668579 PMCID: PMC6342299 DOI: 10.1371/journal.pone.0211048] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 12/30/2018] [Indexed: 12/12/2022] Open
Abstract
Phenylalanine hydroxylase (PAH) deficiency is responsible for most cases of phenylketonuria (PKU). Furthermore, numerous studies on BH4-sensitive PAH deficiency have been conducted. To date, BH4, a cofactor of PAH, has not been used to treat PKU in Russia.Genotype data of patients with PKU can be used to predict their sensitivity to BH4 therapy. A cohort of 2579 patients with PKU from Russia was analyzed for 25 common PAH gene mutations using custom allele-specific multiplex ligation-dependent probe amplification-based technology. A mutation detection rate of 84.1% chromosomes was accomplished. Both pathogenic alleles were identified in 73.1% of patients. The most frequent pathogenic variants were p.Arg408Trp (50.9%), p.Arg261Gln (5.3%), p.Pro281Leu (3.5%), IVS12+1G>A (3.1%), IVS10-11G>A (2.6%), and p.Arg158Leu (2.4%). The exact boundaries of a PAH exon 5 deletion were defined as EX5del4154ins268 (c.442-2913_509+1173del4154ins268). Severe phenotypes prevailed in the cohort, and classical PKU was observed in 71.8% cases. Due to the genotype-based prediction, 55.9% of the probands were non-responders to the BH4-treatment, and 20.2% were potential responders. Analysis of genotype data is useful to predict BH4 response in PKU patients. The high rate of non-responders among Russian patients was due to the high allele frequency of severe PAH mutations.
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31
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Shirzadeh T, Saeidian AH, Bagherian H, Salehpour S, Setoodeh A, Alaei MR, Youssefian L, Samavat A, Touati A, Fallah MS, Vahidnezhad H, Karimipoor M, Azadmehr S, Raeisi M, Bandehi Sarhadi A, Zafarghandi Motlagh F, Jamali M, Zeinali Z, Abiri M, Zeinali S. Molecular genetics of a cohort of 635 cases of phenylketonuria in a consanguineous population. J Inherit Metab Dis 2018; 41:1159-1167. [PMID: 30159852 DOI: 10.1007/s10545-018-0228-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Revised: 06/09/2018] [Accepted: 06/26/2018] [Indexed: 11/28/2022]
Abstract
Phenylketonuria (PKU) is an inborn error of amino acid metabolism caused by mutations in the phenylalanine hydroxylase (PAH) gene, characterized by intellectual deficit and neuropsychiatric complications in untreated patients with estimated frequency of about one in 10,000 to 15,000 live births. PAH deficiency can be detected by neonatal screening in nearly all cases with hyperphenylalaninemia on a heel prick blood spot. Molecular testing of the PAH gene can then be performed in affected family members. Herein, we report molecular study of 635 patients genetically diagnosed with PKU from all ethnicities in Iran. The disease-causing mutations were found in 611 (96.22%) of cases. To the best of our knowledge, this is the most comprehensive molecular genetics study of PKU in Iran, identifying 100 distinct mutations in the PAH gene, including 15 previously unreported mutations. Interestingly, we found unique cases of PKU with uniparental disomy, germline mosaicism, and coinheritance with another Mendelian single-gene disorder that provides new insights for improving the genetic counseling, prenatal diagnosis (PND), and/or pre-implantation genetic diagnosis (PGD) for the inborn error of metabolism group of disorders.
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Affiliation(s)
- Tina Shirzadeh
- Kawsar Human Genetics Research Center, 41 Majlesi St., Vali Asr St., Tehran, 1595645513, Iran
| | - Amir Hossein Saeidian
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
- Genetic, Genomics and Cancer Biology PhD Program, Thomas Jefferson University, Philadelphia, PA, USA
| | - Hamideh Bagherian
- Kawsar Human Genetics Research Center, 41 Majlesi St., Vali Asr St., Tehran, 1595645513, Iran
| | - Shadab Salehpour
- Department of Pediatric Endocrinology and Metabolism, Mofid Children's Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Genomic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Aria Setoodeh
- Growth and Development Research Center, Tehran University of Medical Sciences, Tehran, Iran
- Department of Pediatrics, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Reza Alaei
- Department of Pediatric Endocrinology and Metabolism, Mofid Children's Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Leila Youssefian
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
- Genetic, Genomics and Cancer Biology PhD Program, Thomas Jefferson University, Philadelphia, PA, USA
- Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Ashraf Samavat
- Genetics Office, CDC, Ministry of Health of Iran, Tehran, Iran
| | - Andrew Touati
- Drexel University College of Medicine, Philadelphia, PA, USA
| | - Mohammad-Sadegh Fallah
- Kawsar Human Genetics Research Center, 41 Majlesi St., Vali Asr St., Tehran, 1595645513, Iran
| | - Hassan Vahidnezhad
- Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
- Department of Molecular Medicine, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Morteza Karimipoor
- Department of Molecular Medicine, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Sarah Azadmehr
- Kawsar Human Genetics Research Center, 41 Majlesi St., Vali Asr St., Tehran, 1595645513, Iran
| | - Marzieh Raeisi
- Research Institute for Endocrine Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Department of cellular and molecular biology, Islamic Azad University North Tehran branch, Tehran, Iran
| | - Ameneh Bandehi Sarhadi
- Kawsar Human Genetics Research Center, 41 Majlesi St., Vali Asr St., Tehran, 1595645513, Iran
| | | | - Mojdeh Jamali
- Kawsar Human Genetics Research Center, 41 Majlesi St., Vali Asr St., Tehran, 1595645513, Iran
| | - Zahra Zeinali
- Kawsar Human Genetics Research Center, 41 Majlesi St., Vali Asr St., Tehran, 1595645513, Iran
| | - Maryam Abiri
- Department of Medical Genetics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
| | - Sirous Zeinali
- Kawsar Human Genetics Research Center, 41 Majlesi St., Vali Asr St., Tehran, 1595645513, Iran.
- Department of Molecular Medicine, Biotech Research Center, Pasteur Institute of Iran, Tehran, Iran.
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Klaassen K, Djordjevic M, Skakic A, Desviat LR, Pavlovic S, Perez B, Stojiljkovic M. Functional Characterization of Novel Phenylalanine Hydroxylase p.Gln226Lys Mutation Revealed Its Non-responsiveness to Tetrahydrobiopterin Treatment in Hepatoma Cellular Model. Biochem Genet 2018; 56:533-541. [PMID: 29654578 DOI: 10.1007/s10528-018-9858-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 04/08/2018] [Indexed: 01/20/2023]
Abstract
Treatment with tetrahydrobiopterin (BH4) is the latest therapeutic option approved for patients with phenylketonuria (PKU)-one of the most frequent inborn metabolic diseases. PKU or phenylalanine hydroxylase (PAH) deficiency is caused by mutations in the PAH gene. Given that some PAH mutations are responsive to BH4 treatment while others are non-responsive, for every novel mutation that is discovered it is essential to confirm its pathogenic effect and to assess its responsiveness to a BH4 treatment in vitro, before the drug is administered to patients. We found a c.676C>A (p.Gln226Lys) mutation in the PAH gene in two unrelated patients with PKU. The corresponding aberrant protein has never been functionally characterized in vitro and its response to BH4 treatment is unknown. Computational analyses proposed that glutamine at position 226 is an important, evolutionary conserved amino acid while the substitution with lysine probably disturbs tertiary protein structure and impacts posttranslational PAH modifications. Using hepatoma cellular model, we demonstrated that the amount of mutant p.Gln226Lys PAH detected by Western blot was only 1.2% in comparison to wild-type PAH. The addition of sepiapterin, intracellular precursor of BH4, did not increase PAH protein yield thus marking p.Gln226Lys as BH4-non-responsive mutation. Therefore, computational, experimental, and clinical data were all in accordance showing that p.Gln226Lys is a severe pathogenic PAH mutation. Its non-responsiveness to BH4 treatment in hepatoma cellular model should be considered when deciding treatment options for PKU patients carrying this mutation. Consequently, our study will facilitate clinical genetic practice, particularly genotype-based stratification of PKU treatment.
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Affiliation(s)
- Kristel Klaassen
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444a, Belgrade, 11010, Serbia
| | - Maja Djordjevic
- Mother and Child Health Care Institute of Serbia "Dr Vukan Cupic", School of Medicine, University of Belgrade, Radoja Dakića 6-8, Belgrade, 11070, Serbia
| | - Anita Skakic
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444a, Belgrade, 11010, Serbia
| | - Lourdes R Desviat
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biologia Molecular, Universidad Autonoma de Madrid, CBMSO, UAM, CIBERER, Madrid, Spain
| | - Sonja Pavlovic
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444a, Belgrade, 11010, Serbia
| | - Belen Perez
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biologia Molecular, Universidad Autonoma de Madrid, CBMSO, UAM, CIBERER, Madrid, Spain
| | - Maja Stojiljkovic
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444a, Belgrade, 11010, Serbia.
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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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Eichinger A, Danecka MK, Möglich T, Borsch J, Woidy M, Büttner L, Muntau AC, Gersting SW. Secondary BH4 deficiency links protein homeostasis to regulation of phenylalanine metabolism. Hum Mol Genet 2018; 27:1732-1742. [PMID: 29514280 DOI: 10.1093/hmg/ddy079] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 02/28/2018] [Indexed: 01/01/2023] Open
Abstract
Metabolic control of phenylalanine concentrations in body fluids is essential for cognitive development and executive function. The hepatic phenylalanine hydroxylating system is regulated by the ratio of l-phenylalanine, which is substrate of phenylalanine hydroxylase (PAH), to the PAH cofactor tetrahydrobiopterin (BH4). Physiologically, phenylalanine availability is governed by nutrient intake, whereas liver BH4 is kept at constant level. In phenylketonuria, PAH deficiency leads to elevated blood phenylalanine and is often caused by PAH protein misfolding with loss of function. Here, we report secondary hepatic BH4 deficiency in Pah-deficient mice. Alterations in de novo synthesis and turnover of BH4 were ruled out as molecular causes. We demonstrate that kinetically instable and aggregation-prone variant Pah proteins trap BH4, shifting the pool of free BH4 towards bound BH4. Interference of PAH protein misfolding with metabolite-based control of l-phenylalanine turnover suggests a mechanistic link between perturbation of protein homeostasis and disturbed regulation of metabolic pathways.
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Affiliation(s)
- Anna Eichinger
- Molecular Pediatrics, Dr von Hauner Children's Hospital, Ludwig-Maximilians-Universität, Munich, Germany
| | | | - Tamara Möglich
- Molecular Pediatrics, Dr von Hauner Children's Hospital, Ludwig-Maximilians-Universität, Munich, Germany
| | - Julia Borsch
- Molecular Pediatrics, Dr von Hauner Children's Hospital, Ludwig-Maximilians-Universität, Munich, Germany
| | - Mathias Woidy
- University Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Lars Büttner
- Molecular Pediatrics, Dr von Hauner Children's Hospital, Ludwig-Maximilians-Universität, Munich, Germany
| | - Ania C Muntau
- University Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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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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Choi R, Lee J, Park HD, Park JE, Kim YH, Ki CS, Lee SY, Song J, Kim JW, Lee DH. Reassessing the significance of the PAH c.158G>A (p.Arg53His) variant in patients with hyperphenylalaninemia. J Pediatr Endocrinol Metab 2017; 30:1211-1218. [PMID: 29032371 DOI: 10.1515/jpem-2017-0158] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 08/21/2017] [Indexed: 11/15/2022]
Abstract
BACKGROUND The accurate interpretation of sequence variation is critical for successful molecular diagnoses. It is also fundamental to the accurate diagnosis and treatment of phenylketonuria (PKU). This study aims to evaluate the significance of the c.158G>A (p.Arg53His) variant in the PAH gene, which was previously reported to be a pathogenic mutation that results in decreased phenylalanine hydroxylase enzyme activity in hyperphenylalaninemia (HPA) patients. METHODS Seven unrelated Korean patients with HPA genotyped with the c.158G>A variant were included in this study. The variant c.158G>A was classified by the standards and guidelines for the interpretation of sequence variants by the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. RESULTS By both directly collecting genetic data and comprehensively reviewing the existing literature, we found that this variant is more appropriately classified as "Likely benign" rather than pathogenic. The allele's frequency is 2.57% in the general Korean population, which was greater than expected for phenylketonuria. This variant was observed to be homozygous in healthy subjects and was also observed in cis with other pathogenic variants. It is common in East Asian populations (especially in Koreans) compared to Western populations. There is a possibility that it causes decreased enzyme activity without leading to the full pathology of phenylketonuria. CONCLUSIONS This study expands our understanding of the consequences of variation in PAH and its relationship to HPA.
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van Wegberg AMJ, MacDonald A, Ahring K, Bélanger-Quintana A, Blau N, Bosch AM, Burlina A, Campistol J, Feillet F, Giżewska M, Huijbregts SC, Kearney S, Leuzzi V, Maillot F, Muntau AC, van Rijn M, Trefz F, Walter JH, van Spronsen FJ. The complete European guidelines on phenylketonuria: diagnosis and treatment. Orphanet J Rare Dis 2017; 12:162. [PMID: 29025426 PMCID: PMC5639803 DOI: 10.1186/s13023-017-0685-2] [Citation(s) in RCA: 421] [Impact Index Per Article: 60.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 07/11/2017] [Indexed: 12/22/2022] Open
Abstract
Phenylketonuria (PKU) is an autosomal recessive inborn error of phenylalanine metabolism caused by deficiency in the enzyme phenylalanine hydroxylase that converts phenylalanine into tyrosine. If left untreated, PKU results in increased phenylalanine concentrations in blood and brain, which cause severe intellectual disability, epilepsy and behavioural problems. PKU management differs widely across Europe and therefore these guidelines have been developed aiming to optimize and standardize PKU care. Professionals from 10 different European countries developed the guidelines according to the AGREE (Appraisal of Guidelines for Research and Evaluation) method. Literature search, critical appraisal and evidence grading were conducted according to the SIGN (Scottish Intercollegiate Guidelines Network) method. The Delphi-method was used when there was no or little evidence available. External consultants reviewed the guidelines. Using these methods 70 statements were formulated based on the highest quality evidence available. The level of evidence of most recommendations is C or D. Although study designs and patient numbers are sub-optimal, many statements are convincing, important and relevant. In addition, knowledge gaps are identified which require further research in order to direct better care for the future.
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Affiliation(s)
- A. M. J. van Wegberg
- Division of Metabolic Diseases, Beatrix Children’s Hospital, University Medical Center Groningen, PO BOX 30.001, 9700 RB Groningen, The Netherlands
| | - A. MacDonald
- Dietetic Department, Birmingham Children’s Hospital, Birmingham, UK
| | - K. Ahring
- Department of PKU, Kennedy Centre, Glostrup, Denmark
| | - A. Bélanger-Quintana
- Metabolic Diseases Unit, Department of Paediatrics, Hospital Ramon y Cajal Madrid, Madrid, Spain
| | - N. Blau
- University Children’s Hospital, Dietmar-Hoppe Metabolic Centre, Heidelberg, Germany
- University Children’s Hospital Zürich, Zürich, Switzerland
| | - A. M. Bosch
- Department of Paediatrics, Division of Metabolic Disorders, Academic Medical Centre, University Hospital of Amsterdam, Amsterdam, The Netherlands
| | - A. Burlina
- Division of Inherited Metabolic Diseases, Department of Paediatrics, University Hospital of Padova, Padova, Italy
| | - J. Campistol
- Neuropaediatrics Department, Hospital Sant Joan de Déu, Universitat de Barcelona, Barcelona, Spain
| | - F. Feillet
- Department of Paediatrics, Hôpital d’Enfants Brabois, CHU Nancy, Vandoeuvre les Nancy, France
| | - M. Giżewska
- Department of Paediatrics, Endocrinology, Diabetology, Metabolic Diseases and Cardiology of the Developmental Age, Pomeranian Medical University, Szczecin, Poland
| | - S. C. Huijbregts
- Department of Clinical Child and Adolescent Studies-Neurodevelopmental Disorders, Faculty of Social Sciences, Leiden University, Leiden, The Netherlands
| | - S. Kearney
- Clinical Psychology Department, Birmingham Children’s Hospital, Birmingham, UK
| | - V. Leuzzi
- Department of Paediatrics, Child Neurology and Psychiatry, Sapienza University of Rome, Via dei Sabelli 108, 00185 Rome, Italy
| | - F. Maillot
- CHRU de Tours, Université François Rabelais, INSERM U1069, Tours, France
| | - A. C. Muntau
- University Children’s Hospital, University Medical Centre Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - M. van Rijn
- Division of Metabolic Diseases, Beatrix Children’s Hospital, University Medical Center Groningen, PO BOX 30.001, 9700 RB Groningen, The Netherlands
| | - F. Trefz
- Department of Paediatrics, University of Heidelberg, Heidelberg, Germany
| | - J. H. Walter
- Medicine, Manchester Academic Health Sciences Centre, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
| | - F. J. van Spronsen
- Division of Metabolic Diseases, Beatrix Children’s Hospital, University Medical Center Groningen, PO BOX 30.001, 9700 RB Groningen, The Netherlands
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Zhu T, Ye J, Han L, Qiu W, Zhang H, Liang L, Gu X. The Predictive Value of Genetic Analyses in the Diagnosis of Tetrahydrobiopterin (BH4)-Responsiveness in Chinese Phenylalanine Hydroxylase Deficiency Patients. Sci Rep 2017; 7:6762. [PMID: 28754886 PMCID: PMC5533732 DOI: 10.1038/s41598-017-06462-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 06/13/2017] [Indexed: 11/23/2022] Open
Abstract
Molecular characterization of PAH deficiency has been proven essential in establishing treatment options. We examine the diagnostic accuracy of two genetic assays to predict BH4 responsiveness: to determine whether the AV sum test or mutation-status assessment test can obviate the need for BH4 loading in Chinese patients. The overall predicted response in 346 patients was 31.65% by the AV sum test and 25.43% by the other assay; both percentages were lower than 51.06% derived from loading results in 94 patients. Responders were compound heterozygotes with definite BH4 responsive mutations, while non-responders had null/null ones; some consistently with specific mutations and genotypes. The sensitivity and specificity of the assays were 81.1% and 92.5% for the AV sum, and 82.9%, 97.3% for the other. An AV sum cutoff >2 has a positive predictive value (PPV) of 90.9%, while the presence of at least one BH4 responsive mutation has a PPV of 97.1%. The two approaches showed good concordance. Our data confirmed that the mutation-status assessment has a higher diagnostic accuracy in predicting response for Chinese patients than the AV sum test. BH4-responsiveness may be predicted or excluded from patients' molecular characteristics to some extent, thus some patients may avoid the initial loading.
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Affiliation(s)
- Tianwen Zhu
- Department of Neonatal Medicine, Xin-Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jun Ye
- Department of Endocrinology and Genetic Metabolism, Xin-Hua Hospital, Shanghai Institute of Pediatric Research Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lianshu Han
- Department of Endocrinology and Genetic Metabolism, Xin-Hua Hospital, Shanghai Institute of Pediatric Research Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Wenjuan Qiu
- Department of Endocrinology and Genetic Metabolism, Xin-Hua Hospital, Shanghai Institute of Pediatric Research Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Huiwen Zhang
- Department of Endocrinology and Genetic Metabolism, Xin-Hua Hospital, Shanghai Institute of Pediatric Research Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lili Liang
- Department of Endocrinology and Genetic Metabolism, Xin-Hua Hospital, Shanghai Institute of Pediatric Research Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xuefan Gu
- Department of Endocrinology and Genetic Metabolism, Xin-Hua Hospital, Shanghai Institute of Pediatric Research Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.
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Gundorova P, Stepanova AA, Bushueva TV, Belyashova EY, Zinchenko RA, Amelina SS, Kutsev SI, Polyakov AV. Genotyping of patients with phenylketonuria from different regions of Russia for determining BH4 responsiveness. RUSS J GENET+ 2017. [DOI: 10.1134/s1022795417060060] [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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41
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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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Khan MA, Khan S, Windpassinger C, Badar M, Nawaz Z, Mohammad RM. The Molecular Genetics of Autosomal Recessive Nonsyndromic Intellectual Disability: a Mutational Continuum and Future Recommendations. Ann Hum Genet 2017; 80:342-368. [PMID: 27870114 DOI: 10.1111/ahg.12176] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 10/03/2016] [Indexed: 12/19/2022]
Abstract
Intellectual disability (ID) is a clinical manifestation of the central nervous system without any major dysmorphologies of the brain. Biologically it affects learning capabilities, memory, and cognitive functioning. The basic defining features of ID are characterized by IQ<70, age of onset before 18 years, and impairment of at least two of the adaptive skills. Clinically it is classified in a syndromic (with additional abnormalities) and a nonsyndromic form (with only cognitive impairment). The study of nonsyndromic intellectual disability (NSID) can best explain the pathophysiology of cognition, intelligence and memory. Genetic analysis in autosomal recessive nonsyndrmic ID (ARNSID) has mapped 51 disease loci, 34 of which have revealed their defective genes. These genes play diverse physiological roles in various molecular processes, including methylation, proteolysis, glycosylation, signal transduction, transcription regulation, lipid metabolism, ion homeostasis, tRNA modification, ubiquitination and neuromorphogenesis. High-density SNP array and whole exome sequencing has increased the pace of gene discoveries and many new mutations are being published every month. The lack of uniform criteria has assigned multiple identifiers (or accession numbers) to the same MRT locus (e.g. MRT7 and MRT22). Here in this review we describe the molecular genetics of ARNSID, prioritize the candidate genes in uncharacterized loci, and propose a new nomenclature to reorganize the mutation data that will avoid the confusion of assigning duplicate accession numbers to the same ID locus and to make the data manageable in the future as well.
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Affiliation(s)
- Muzammil Ahmad Khan
- Genomic Core Facility, Translational Research Institute, Academic Health System, Hamad Medical Corporation, Doha, 3050, Qatar.,Gomal Centre of Biochemistry and Biotechnology, Gomal University, D.I.Khan, 29050 KPK, Pakistan
| | - Saadullah Khan
- Genomic Core Facility, Translational Research Institute, Academic Health System, Hamad Medical Corporation, Doha, 3050, Qatar.,Department of Biotechnology and Genetic Engineering, Kohat University of Science and Technology, Kohat, KPK, Pakistan
| | | | - Muhammad Badar
- Gomal Centre of Biochemistry and Biotechnology, Gomal University, D.I.Khan, 29050 KPK, Pakistan
| | - Zafar Nawaz
- Genomic Core Facility, Translational Research Institute, Academic Health System, Hamad Medical Corporation, Doha, 3050, Qatar
| | - Ramzi M Mohammad
- Genomic Core Facility, Translational Research Institute, Academic Health System, Hamad Medical Corporation, Doha, 3050, Qatar
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Bell SM, Wendt DJ, Zhang Y, Taylor TW, Long S, Tsuruda L, Zhao B, Laipis P, Fitzpatrick PA. Formulation and PEGylation optimization of the therapeutic PEGylated phenylalanine ammonia lyase for the treatment of phenylketonuria. PLoS One 2017; 12:e0173269. [PMID: 28282402 PMCID: PMC5345807 DOI: 10.1371/journal.pone.0173269] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 02/11/2017] [Indexed: 01/03/2023] Open
Abstract
Phenylketonuria (PKU) is a genetic metabolic disease in which the decrease or loss of phenylalanine hydroxylase (PAH) activity results in elevated, neurotoxic levels of phenylalanine (Phe). Due to many obstacles, PAH enzyme replacement therapy is not currently an option. Treatment of PKU with an alternative enzyme, phenylalanine ammonia lyase (PAL), was first proposed in the 1970s. However, issues regarding immunogenicity, enzyme production and mode of delivery needed to be overcome. Through the evaluation of PAL enzymes from multiple species, three potential PAL enzymes from yeast and cyanobacteria were chosen for evaluation of their therapeutic potential. The addition of polyethylene glycol (PEG, MW = 20,000), at a particular ratio to modify the protein surface, attenuated immunogenicity in an animal model of PKU. All three PEGylated PAL candidates showed efficacy in a mouse model of PKU (BTBR Pahenu2) upon subcutaneous injection. However, only PEGylated Anabaena variabilis (Av) PAL-treated mice demonstrated sustained low Phe levels with weekly injection and was the only PAL evaluated that maintained full enzymatic activity upon PEGylation. A PEGylated recombinant double mutant version of AvPAL (Cys503Ser/Cys565Ser), rAvPAL-PEG, was selected for drug development based on its positive pharmacodynamic profile and favorable expression titers. PEGylation was shown to be critical for rAvPAL-PEG efficacy as under PEGylated rAvPAL had a lower pharmacodynamic effect. rAvPAL and rAvPAL-PEG had poor stability at 4°C. L-Phe and trans-cinnamate were identified as activity stabilizing excipients. rAvPAL-PEG is currently in Phase 3 clinical trials to assess efficacy in PKU patients.
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Affiliation(s)
- Sean M. Bell
- BioMarin Pharmaceutical, Novato, California, United States of America
- * E-mail:
| | - Dan J. Wendt
- BioMarin Pharmaceutical, Novato, California, United States of America
| | - Yanhong Zhang
- BioMarin Pharmaceutical, Novato, California, United States of America
| | - Timothy W. Taylor
- BioMarin Pharmaceutical, Novato, California, United States of America
| | - Shinong Long
- BioMarin Pharmaceutical, Novato, California, United States of America
| | - Laurie Tsuruda
- BioMarin Pharmaceutical, Novato, California, United States of America
| | - Bin Zhao
- BioMarin Pharmaceutical, Novato, California, United States of America
| | - Phillip Laipis
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida, United States of America
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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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45
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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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47
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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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Jeannesson-Thivisol E, Feillet F, Chéry C, Perrin P, Battaglia-Hsu SF, Herbeth B, Cano A, Barth M, Fouilhoux A, Mention K, Labarthe F, Arnoux JB, Maillot F, Lenaerts C, Dumesnil C, Wagner K, Terral D, Broué P, de Parscau L, Gay C, Kuster A, Bédu A, Besson G, Lamireau D, Odent S, Masurel A, Guéant JL, Namour F. Genotype-phenotype associations in French patients with phenylketonuria and importance of genotype for full assessment of tetrahydrobiopterin responsiveness. Orphanet J Rare Dis 2015; 10:158. [PMID: 26666653 PMCID: PMC5024853 DOI: 10.1186/s13023-015-0375-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 12/08/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Mutations in Phenylalanine Hydroxylase (PAH) gene cause phenylketonuria. Sapropterin (BH4), the enzyme cofactor, is an important therapeutical strategy in phenylketonuria. However, PAH is a highly polymorphic gene and it is difficult to identify BH4-responsive genotypes. We seek here to improve prediction of BH4-responsiveness through comparison of genotypes, BH4-loading test, predictions of responsiveness according to the literature and types and locations of mutations. METHODS A total of 364 French patients among which, 9 % had mild hyperphenylalaninemia, 17.7 % mild phenylketonuria and 73.1 % classical phenylketonuria, benefited from a 24-hour BH4-loading test and had the PAH gene sequenced and analyzed by Multiplex Ligation Probe Amplification. RESULTS Overall, 31.6 % of patients were BH4-responsive. The number of different mutations found was 127, including 26 new mutations. The mutations c.434A > T, c.500A > T, c.529G > C, c.1045 T > G and c.1196 T > C were newly classified as being BH4-responsive. We identified 261 genotypes, among which 46 were newly recognized as being BH4-responsive. Even though patients carry 2 responsive alleles, BH4-responsiveness cannot be predicted with certainty unless they present mild hyperphenylalaninemia. BH4-responsiveness cannot be predicted in patients carrying one responsive mutation only. In general, the milder the phenotype is, the stronger the BH4-response is. Almost exclusively missense mutations, particularly in exons 12, 11 and 8, are associated with BH4-responsiveness and any other type of mutation predicts a negative response. CONCLUSIONS This study is the first of its kind, in a French population, to identify the phenotype associated with several combinations of PAH mutations. As others, it highlights the necessity of performing simultaneously BH4 loading test and molecular analysis in monitoring phenylketonuria patients.
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Affiliation(s)
- Elise Jeannesson-Thivisol
- Reference Center for Inherited Metabolic Diseases, University Hospital of Nancy, 9 ave Forêt de Haye, BP 184, 54511, Vandoeuvre-lès-Nancy, France
- INSERM U954, Department of Nutrition-Genetics-Environmental Risk Exposure, University of Lorraine, 9 ave Forêt de Haye, BP 184, 54511, Vandoeuvre-lès-Nancy, France
| | - François Feillet
- Reference Center for Inherited Metabolic Diseases, University Hospital of Nancy, 9 ave Forêt de Haye, BP 184, 54511, Vandoeuvre-lès-Nancy, France
- INSERM U954, Department of Nutrition-Genetics-Environmental Risk Exposure, University of Lorraine, 9 ave Forêt de Haye, BP 184, 54511, Vandoeuvre-lès-Nancy, France
| | - Céline Chéry
- Reference Center for Inherited Metabolic Diseases, University Hospital of Nancy, 9 ave Forêt de Haye, BP 184, 54511, Vandoeuvre-lès-Nancy, France
- INSERM U954, Department of Nutrition-Genetics-Environmental Risk Exposure, University of Lorraine, 9 ave Forêt de Haye, BP 184, 54511, Vandoeuvre-lès-Nancy, France
| | - Pascal Perrin
- Reference Center for Inherited Metabolic Diseases, University Hospital of Nancy, 9 ave Forêt de Haye, BP 184, 54511, Vandoeuvre-lès-Nancy, France
- INSERM U954, Department of Nutrition-Genetics-Environmental Risk Exposure, University of Lorraine, 9 ave Forêt de Haye, BP 184, 54511, Vandoeuvre-lès-Nancy, France
| | - Shyue-Fang Battaglia-Hsu
- Reference Center for Inherited Metabolic Diseases, University Hospital of Nancy, 9 ave Forêt de Haye, BP 184, 54511, Vandoeuvre-lès-Nancy, France
- INSERM U954, Department of Nutrition-Genetics-Environmental Risk Exposure, University of Lorraine, 9 ave Forêt de Haye, BP 184, 54511, Vandoeuvre-lès-Nancy, France
| | - Bernard Herbeth
- Reference Center for Inherited Metabolic Diseases, University Hospital of Nancy, 9 ave Forêt de Haye, BP 184, 54511, Vandoeuvre-lès-Nancy, France
- INSERM U954, Department of Nutrition-Genetics-Environmental Risk Exposure, University of Lorraine, 9 ave Forêt de Haye, BP 184, 54511, Vandoeuvre-lès-Nancy, France
| | - Aline Cano
- Reference Center for Inherited Metabolic Diseases, Timone Hospital, Marseille, France
| | - Magalie Barth
- Department of Biochemistry and Genetics, Angers University Hospital, Angers, France
| | - Alain Fouilhoux
- Reference Center for Inherited Metabolic Diseases, Hospices Civils de Lyon, Bron, France
| | - Karine Mention
- Reference Center for Inherited Metabolic Diseases, Jeanne de Flandres Hospital, Lille, France
| | - François Labarthe
- Department of Pediatric Medicine, Clocheville Hospital, Tours, France
| | - Jean-Baptiste Arnoux
- Reference Center for Inherited Metabolic Diseases, Necker-Enfants Malades Hospital, Paris, France
| | - François Maillot
- Department of Internal Medicine, Tours University Hospital, Tours, France
| | | | - Cécile Dumesnil
- Pediatric Hematology and Oncology, Rouen University-Hospital, Rouen, France
| | - Kathy Wagner
- Department of Pediatrics, Lenval Hospital, Nice, France
| | - Daniel Terral
- Department of Pediatrics, Hotel-Dieu Hospital, Clermont-Ferrand, France
| | - Pierre Broué
- Department of Pediatric Hepatology and Metabolic Diseases, Children Hospital, Toulouse, France
| | | | - Claire Gay
- Department of Pediatrics, Saint-Etienne University-Hospital, Saint-Etienne, France
| | - Alice Kuster
- Pediatric Department, Nantes University Hospital, Nantes, France
| | - Antoine Bédu
- Neonatology Department, Mère-Enfant Hospital, Limoges, France
| | - Gérard Besson
- Department of Neurology, University Hospital of Grenoble, Grenoble, France
| | - Delphine Lamireau
- Department of Pediatrics, Pellegrin-Enfants Hospital, Bordeaux, France
| | - Sylvie Odent
- Department of Clinical Genetics, Rennes University Hospital, Rennes, France
| | - Alice Masurel
- Department of Medical Genetics, Dijon University-Hospital, Dijon, France
| | - Jean-Louis Guéant
- Reference Center for Inherited Metabolic Diseases, University Hospital of Nancy, 9 ave Forêt de Haye, BP 184, 54511, Vandoeuvre-lès-Nancy, France
- INSERM U954, Department of Nutrition-Genetics-Environmental Risk Exposure, University of Lorraine, 9 ave Forêt de Haye, BP 184, 54511, Vandoeuvre-lès-Nancy, France
| | - Fares Namour
- Reference Center for Inherited Metabolic Diseases, University Hospital of Nancy, 9 ave Forêt de Haye, BP 184, 54511, Vandoeuvre-lès-Nancy, France.
- INSERM U954, Department of Nutrition-Genetics-Environmental Risk Exposure, University of Lorraine, 9 ave Forêt de Haye, BP 184, 54511, Vandoeuvre-lès-Nancy, France.
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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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50
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Trunzo R, Santacroce R, D'Andrea G, Longo V, De Girolamo G, Dimatteo C, Leccese A, Bafunno V, Lillo V, Papadia F, Margaglione M. Phenylalanine hydroxylase deficiency in south Italy: Genotype-phenotype correlations, identification of a novel mutant PAH allele and prediction of BH4 responsiveness. Clin Chim Acta 2015; 450:51-5. [PMID: 26210745 DOI: 10.1016/j.cca.2015.07.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Revised: 07/13/2015] [Accepted: 07/14/2015] [Indexed: 10/23/2022]
Abstract
We investigated the mutation spectrum of the phenylalanine hydroxylase gene (PAH) in a cohort of patients from 33 Italian PKU families. Mutational screening of the known coding region, including conventional intron splice sites, was performed by direct sequencing of the patients' genomic DNA. Thirty-three different disease causing mutations were identified in our patient group, including 19 missense, 6 splicing, 3 nonsense, 5 deletions, with a detection rate of 100%. The most prevalent mutation was the IVS10-11G>A, accounting for 12.1% of PKU alleles studied. Other frequent mutations were: p.R261Q (9.1%), p.P281L (7.6%), and p.R408W (6.1%). We also identified one novel missense mutation, p.H290Q. A spectrum of 31 different genotypes was observed and a genotype based predictions of BH4-responsiveness were assessed. Among all genotypes, 13 were predicted to be BH4-responsive represented by thirteen PKU families. In addition, genotype-phenotype correlations were performed. This study reveals the importance of a full genotyping of PKU patients and the prediction of BH4-responsiveness, not only because of the definitive diagnosis and prediction of the optimal diet, but also to point out those patients that could benefit from new therapeutic approach. They may potentially benefit from BH4 therapy which, combined with a less strict diet, or eventually in special cases as monotherapy, may contribute to reduce nutritional deficiencies and minimize neurological and psychological dysfunctions.
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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
| | - Giovanna D'Andrea
- Genetica Medica, Dipartimento di Medicina Clinica e Sperimentale, Università degli Studi di Foggia, Italy
| | - Vittoria Longo
- 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
| | - Claudia Dimatteo
- Genetica Medica, Dipartimento di Medicina Clinica e Sperimentale, Università degli Studi di Foggia, Italy
| | - Angelica Leccese
- Genetica Medica, Dipartimento di Medicina Clinica e Sperimentale, Università degli Studi di Foggia, Italy
| | - Valeria Bafunno
- 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
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