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Çıkı K, Yıldız Y, Kahraman AB, Özgül RK, Coşkun T, Dursun A, Tokatlı A, Sivri S. Predictors of eventual requirement of phenylalanine-restricted diet in young infants with phenylalanine hydroxylase deficiency initially managed with sapropterin monotherapy. Mol Genet Metab 2023; 140:107706. [PMID: 37837865 DOI: 10.1016/j.ymgme.2023.107706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Revised: 10/02/2023] [Accepted: 10/02/2023] [Indexed: 10/16/2023]
Abstract
BACKGROUND Phenylalanine (Phe)-restricted diet is associated with lower quality of life for patients with phenylketonuria (PKU), and a concern for caregivers of recently-diagnosed infants. Sapropterin is an oral drug used as an alternative or adjunct to dietary treatment. We have observed that some of the young infants initially managed successfully with sapropterin monotherapy have required dietary treatment in long-term follow-up. We aimed to determine the baseline factors associated with future initiation of dietary treatment in these patients. METHODS Data were obtained retrospectively from the medical records of 80 PKU patients started on sapropterin monotherapy before 3 months of age between 2011 and 2021. RESULTS The patients were followed for a median of 3.9 years (Q1-Q3: 2.5-5.75 years). Sapropterin was tapered down and discontinued in 5 patients (6.3%) as their Phe levels remained below 360 μmol/L without treatment. Sapropterin monotherapy was sufficient in 62 patients (77.5%), while 13 (16.2%) required dietary treatment. Phe and tyrosine (Tyr) levels, and Phe:Tyr ratios differed significantly among the patients maintained on sapropterin monotherapy and those started on dietary treatment, but the Phe:Tyr ratio at diagnosis was the most important independent baseline variable (OR: 1.61, 95% CI: 1.15-2.27, p = 0.006), with Phe:Tyr ratio at diagnosis >5.25 associated with dietary treatment (sensitivity: 90.0%, specificity: 81.8%). Genotypic phenotype value (GPV), unavailable at baseline, was also associated with dietary treatment (median GPV 9.2 vs. 3.8, p = 0.006), but some genotypes were not specific to the final treatment modality. DISCUSSION We propose that the Phe:Tyr ratio at diagnosis is an important indicator to predict dietary requirement in young infants initially managed with sapropterin monotherapy.
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Affiliation(s)
- Kısmet Çıkı
- Division of Pediatric Metabolism, Department of Pediatrics, Faculty of Medicine, Hacettepe University, Ankara, Turkey.
| | - Yılmaz Yıldız
- Division of Pediatric Metabolism, Department of Pediatrics, Faculty of Medicine, Hacettepe University, Ankara, Turkey.
| | - Ayça Burcu Kahraman
- Division of Pediatric Metabolism, Department of Pediatrics, Faculty of Medicine, Hacettepe University, Ankara, Turkey.
| | - R Köksal Özgül
- Hacettepe University Institute of Child Health, Ankara, Turkey.
| | - Turgay Coşkun
- Division of Pediatric Metabolism, Department of Pediatrics, Faculty of Medicine, Hacettepe University, Ankara, Turkey.
| | - Ali Dursun
- Division of Pediatric Metabolism, Department of Pediatrics, Faculty of Medicine, Hacettepe University, Ankara, Turkey.
| | - Ayşegül Tokatlı
- Division of Pediatric Metabolism, Department of Pediatrics, Faculty of Medicine, Hacettepe University, Ankara, Turkey.
| | - Serap Sivri
- Division of Pediatric Metabolism, Department of Pediatrics, Faculty of Medicine, Hacettepe University, Ankara, Turkey.
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Evers RAF, van Wegberg AMJ, Anjema K, Lubout CMA, van Dam E, van Vliet D, Blau N, van Spronsen FJ. The first European guidelines on phenylketonuria: Usefulness and implications for BH 4 responsiveness testing. J Inherit Metab Dis 2020; 43:244-250. [PMID: 31503351 DOI: 10.1002/jimd.12173] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 08/28/2019] [Accepted: 09/09/2019] [Indexed: 01/27/2023]
Abstract
OBJECTIVE This study aimed to investigate and improve the usefulness of the 48-hour BH4 loading test and to assess genotype for BH4 responsiveness prediction, using the new definition of BH4 responsiveness from the European guidelines, as well as an amended definition. METHOD Applying the definition of the European guidelines (≥100% increase in natural protein tolerance) and an amended definition (≥100% increase in natural protein tolerance or tolerating a safe natural protein intake) to a previous dataset, we first assessed the positive predictive value (PPV) of the 48-hour BH4 loading test using a cutoff value of 30%. Then, we tried to improve this PPV by using different cutoff values and separate time points. Last, using the BIOPKU database, we compared predicted BH4 responsiveness (according to genotype) and genotypic phenotype values (GPVs) in BH4 -responsive and BH4 -unresponsive patients. RESULTS The PPV of the 48-hour loading test was 50.0% using the definition of the European guidelines, and 69.4% when applying the amended definition of BH4 responsiveness. Higher cutoff values led to a higher PPV, but resulted in an increase in false-negative tests. Parameters for genotype overlapped between BH4 -responsive and BH4 -unresponsive patients, although BH4 responsiveness was not observed in patients with a GPV below 2.4. CONCLUSION The 48-hour BH4 loading test is not as useful as previously considered and cannot be improved easily, whereas genotype seems mainly helpful in excluding BH4 responsiveness. Overall, the definition of BH4 responsiveness and BH4 responsiveness testing require further attention.
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Affiliation(s)
- Roeland A F Evers
- Beatrix Children's Hospital, Division of Metabolic Diseases, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Annemiek M J van Wegberg
- Beatrix Children's Hospital, Division of Metabolic Diseases, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Karen Anjema
- Beatrix Children's Hospital, Division of Metabolic Diseases, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Charlotte M A Lubout
- Beatrix Children's Hospital, Division of Metabolic Diseases, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Esther van Dam
- Beatrix Children's Hospital, Division of Metabolic Diseases, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Danique van Vliet
- Beatrix Children's Hospital, Division of Metabolic Diseases, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Nenad Blau
- University Children's Hospital Zürich, Zürich, Switzerland
| | - Francjan J van Spronsen
- Beatrix Children's Hospital, Division of Metabolic Diseases, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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Ceberio L, Hermida Á, Venegas E, Arrieta F, Morales M, Forga M, Gonzalo M. Phenylketonuria in the adult patient. Expert Opin Orphan Drugs 2019. [DOI: 10.1080/21678707.2019.1633914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Leticia Ceberio
- Inborn metabolic disease unit, Internal Medicine Service, Hospital Universitario de Cruces, Baracaldo, Vizcaya, Spain
| | - Álvaro Hermida
- Unit of Diagnosis and Treatment of Congenital Metabolic Diseases, Internal Medicine Service, Hospital Clínico Universitario de Santiago, Santiago de Compostela, Spain
| | - Eva Venegas
- Endocrinology and Nutrition Service, C.U.S.R Congenital Metabolic Disease, Hospital Universitario Virgen del Rocío, Sevilla, Spain
| | - Francisco Arrieta
- Departament Endocrinology Metabolism and Nutrion, C.U.S.R Congenital Metabolic Disease, CIBER Physiopathology of Obesity and Nutrition (CIBERobn), Ramón y Cajal Health Research Institute (IRYCIS), Madrid, Spain
| | - Montserrat Morales
- Inborn Metabolic Disease Service, C.S.U.R of Congenital Metabolic Diseases, Internal Medicine Service, Hospital 12 de octubre, Madrid, Spain
| | - Maria Forga
- Endocrinology and Nutrition Department, Hospital Clinic, Barcelona, Spain
| | - Montserrat Gonzalo
- UGC Endocrinology and Nutrition, Hospital Regional Universitario de Málaga, Instituto de Biomedicina de Málaga (IBIMA) & CIBER de Diabetes y Enfermedades Metabólicas asociadas (CIBERDEM), Málaga, Spain
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Ashe K, Kelso W, Farrand S, Panetta J, Fazio T, De Jong G, Walterfang M. Psychiatric and Cognitive Aspects of Phenylketonuria: The Limitations of Diet and Promise of New Treatments. Front Psychiatry 2019; 10:561. [PMID: 31551819 PMCID: PMC6748028 DOI: 10.3389/fpsyt.2019.00561] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 07/17/2019] [Indexed: 12/30/2022] Open
Abstract
Phenylketonuria (PKU) is a recessive disorder of phenylalanine metabolism due to mutations in the gene for phenylalanine hydroxylase (PAH). Reduced PAH activity results in significant hyperphenylalaninemia, which leads to alterations in cerebral myelin and protein synthesis, as well as reduced levels of serotonin, dopamine, and noradrenaline in the brain. When untreated, brain development is grossly disrupted and significant intellectual impairment and behavioral disturbance occur. The advent of neonatal heel prick screening has allowed for diagnosis at birth, and the institution of a phenylalanine restricted diet. Dietary treatment, particularly when maintained across neurodevelopment and well into adulthood, has resulted in markedly improved outcomes at a cognitive and psychiatric level for individuals with PKU. However, few individuals can maintain full dietary control lifelong, and even with good control, an elevated risk remains of-in particular-mood, anxiety, and attentional disorders across the lifespan. Increasingly, dietary recommendations focus on maintaining continuous dietary treatment lifelong to optimize psychiatric and cognitive outcomes, although the effect of long-term protein restricted diets on brain function remains unknown. While psychiatric illness is very common in adult PKU populations, very little data exist to guide clinicians on optimal treatment. The advent of new treatments that do not require restrictive dietary management, such as the enzyme therapy Pegvaliase, holds the promise of allowing patients a relatively normal diet alongside optimized mental health and cognitive functioning.
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Affiliation(s)
- Killian Ashe
- Neuropsychiatry Unit, Royal Melbourne Hospital, Melbourne, VIC, Australia
| | - Wendy Kelso
- Neuropsychiatry Unit, Royal Melbourne Hospital, Melbourne, VIC, Australia
| | - Sarah Farrand
- Neuropsychiatry Unit, Royal Melbourne Hospital, Melbourne, VIC, Australia
| | - Julie Panetta
- Statewide Adult Metabolic Service, Royal Melbourne Hospital, Melbourne, VIC, Australia
| | - Tim Fazio
- Statewide Adult Metabolic Service, Royal Melbourne Hospital, Melbourne, VIC, Australia.,Melbourne Medical School, University of Melbourne, Melbourne, VIC, Australia
| | - Gerard De Jong
- Statewide Adult Metabolic Service, Royal Melbourne Hospital, Melbourne, VIC, Australia.,Melbourne Medical School, University of Melbourne, Melbourne, VIC, Australia
| | - Mark Walterfang
- Neuropsychiatry Unit, Royal Melbourne Hospital, Melbourne, VIC, Australia.,Melbourne Neuropsychiatry Centre, University of Melbourne and North-Western Mental Health, Melbourne, VIC, Australia.,Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC, Australia
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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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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: 455] [Impact Index Per Article: 65.0] [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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7
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Singh RH, Cunningham AC, Mofidi S, Douglas TD, Frazier DM, Hook DG, Jeffers L, McCune H, Moseley KD, Ogata B, Pendyal S, Skrabal J, Splett PL, Stembridge A, Wessel A, Rohr F. Updated, web-based nutrition management guideline for PKU: An evidence and consensus based approach. Mol Genet Metab 2016; 118:72-83. [PMID: 27211276 DOI: 10.1016/j.ymgme.2016.04.008] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 04/15/2016] [Accepted: 04/15/2016] [Indexed: 10/21/2022]
Abstract
BACKGROUND In 2014, recommendations for the nutrition management of phenylalanine hydroxylase deficiency were published as a companion to the concurrently published American College of Medical Genetics and Genomics guideline for the medical treatment of phenylketonuria (PKU). These were developed primarily from a summary of findings from the PKU scientific review conference sponsored by the National Institutes of Health and Agency for Healthcare Research & Quality along with additional systematic literature review. Since that time, the Genetic Metabolic Dietitians International and the Southeast Regional Newborn Screening and Genetics Collaborative have partnered to create a web-based technology platform for the update and development of nutrition management guidelines for inherited metabolic disorders. OBJECTIVE The purpose of this PKU guideline is to establish harmonization in treatment and monitoring, to guide the integration of nutrition therapy in the medical management of PKU, and to improve outcomes (nutritional, cognitive, and developmental) for individuals with PKU in all life stages while reducing associated medical, educational, and social costs. METHODS Six research questions critical to PKU nutrition management were formulated to support guideline development: Review, critical appraisal, and abstraction of peer-reviewed studies and unpublished practice literature, along with expert Delphi survey feedback, nominal group process, and external review from metabolic physicians and dietitians were utilized for development of recommendations relevant to each question. Recommendations address nutrient intake, including updated protein requirements, optimal blood phenylalanine concentrations, nutrition interventions, monitoring parameters specific to life stages, adjunct therapies, and pregnancy and lactation. Recommendations were graded using a rigorous system derived from the Academy of Nutrition and Dietetics. RESULTS AND CONCLUSION These guidelines, updated utilizing a thorough and systematic approach to literature analysis and national consensus process, are now easily accessible to the global community via the newly developed digital platform. For additional details on specific topics, readers are encouraged to review materials on the online portal: https://GMDI.org/.
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Affiliation(s)
- Rani H Singh
- Department of Human Genetics, Emory University School of Medicine, 2165 North Decatur Road, Decatur, Atlanta, GA 30033, USA; Nutrition Health Sciences Program, Graduate Division of Biological and Biomedical Sciences, Emory University School of Arts and Sciences, Atlanta, GA, USA.
| | - Amy C Cunningham
- Hayward Genetics Center, Tulane University School of Medicine, 1430 Tulane Ave, New Orleans, LA 70112, USA.
| | - Shideh Mofidi
- Inherited Metabolic Disease Center, Maria Fareri Childrens Hospital, Westchester Medical Center, New York Medical College, Valhalla, New York, USA.
| | - Teresa D Douglas
- Department of Human Genetics, Emory University School of Medicine, 2165 North Decatur Road, Decatur, Atlanta, GA 30033, USA.
| | - Dianne M Frazier
- Division of Genetics and Metabolism, University of North Carolina School of Medicine, 1100 Manning Drive, Chapel Hill, NC 27599, USA.
| | | | - Laura Jeffers
- Cleveland Clinic, Center for Human Nutrition, 9500 Euclid Ave, Cleveland, OH 44195, USA.
| | - Helen McCune
- Pediatric Genetics and Metabolism, University of Florida, 1600 SW Archer Rd, Gainesville, FL 32607, USA.
| | - Kathryn D Moseley
- Genetics Division, USC/Keck School of Medicine, 1801 Marengo St. Rm. 1G-24, Los Angeles, CA 90033, USA.
| | - Beth Ogata
- University of Washington, Department of Pediatrics, UW-CHDD, Box 357920, Seattle, WA 98195, USA.
| | - Surekha Pendyal
- Division of Genetics and Metabolism, University of North Carolina School of Medicine, 1100 Manning Drive, Chapel Hill, NC 27599, USA.
| | - Jill Skrabal
- Department of Medical Genetics, University of Nebraska Medical Center/Children's Hospital and Medical Center, 981200 Nebraska Medical Center, Omaha, NE. 68198-1200, USA.
| | - Patricia L Splett
- Evaluation Consultant Splett & Associates, LLC, 399 Badger Blvd W., Stanchfield, MN 55080, USA.
| | - Adrya Stembridge
- Department of Human Genetics, Emory University School of Medicine, 2165 North Decatur Road, Decatur, Atlanta, GA 30033, USA.
| | - Ann Wessel
- Division of Genetics and Genomics, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA.
| | - Frances Rohr
- Division of Genetics and Genomics, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA.
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Scala I, Concolino D, Della Casa R, Nastasi A, Ungaro C, Paladino S, Capaldo B, Ruoppolo M, Daniele A, Bonapace G, Strisciuglio P, Parenti G, Andria G. Long-term follow-up of patients with phenylketonuria treated with tetrahydrobiopterin: a seven years experience. Orphanet J Rare Dis 2015; 10:14. [PMID: 25757997 PMCID: PMC4351928 DOI: 10.1186/s13023-015-0227-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 01/15/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Phenylketonuria (PKU) is an autosomal recessive disorder caused by the deficiency of phenylalanine hydroxylase that catalyzes the conversion of phenylalanine to tyrosine, using tetrahydrobiopterin (BH4) as coenzyme. Besides dietary phenylalanine restriction, new therapeutic options are emerging, such as the treatment with BH4 in subgroups of PKU patients responding to a loading test with BH4. METHODS A no-profit open-label interventional trial with long-term oral BH4 therapy, sponsored by the Italian Medicines Agency (AIFA), was performed in a group of 17 PKU patients resulted as BH4 responders among 46 subjects analyzed for BH4-responsiveness (prot. FARM5MATC7). We report on efficacy and safety data of BH4 therapy and analyze factors predicting BH4-responsiveness and long-term response to BH4. A BH4-withdrawal test was used as a proof of the efficacy of long-term therapy with BH4. RESULTS Forty-four percent of the patients responded to the 48 h-long loading test with BH4. All the phenotypic classes were represented. Genotype was the best predictor of responsiveness, along with lower phenylalanine levels at diagnosis, higher tolerance and lower phenylalanine/tyrosine ratio before the test. In BH4 responder patients, long-term BH4 therapy resulted safe and effective in increasing tolerance while maintaining a good metabolic control. The BH4 withdrawal test, performed in a subset of patients, showed that improved tolerance was directly dependent on BH4 assumption. Tolerance to phenylalanine was re-evaluated in 43.5% of patients and was longitudinally analyzed in 5 patients. CONCLUSIONS Long-term treatment with BH4 is safe and effective in increasing tolerance to phenylalanine. There is real need to assess the actual tolerance to phenylalanine in PKU patients to ameliorate quality of life, improve nutritional status, avoiding unnecessarily restricted diets, and interpret the effects of new therapies for PKU.
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Affiliation(s)
- Iris Scala
- Department of Translational Medicine-Section of Pediatrics, Federico II University, Via S. Pansini 5, 80131, Naples, Italy.
| | - Daniela Concolino
- Department of Pediatrics, Magna Graecia University, Catanzaro, Italy.
| | - Roberto Della Casa
- Department of Translational Medicine-Section of Pediatrics, Federico II University, Via S. Pansini 5, 80131, Naples, Italy.
| | - Anna Nastasi
- Department of Clinical Medicine and Surgery, Physiology Nutrition Unit, Federico II University, Naples, Italy.
| | - Carla Ungaro
- Department of Translational Medicine-Section of Pediatrics, Federico II University, Via S. Pansini 5, 80131, Naples, Italy.
| | - Serena Paladino
- Department of Translational Medicine-Section of Pediatrics, Federico II University, Via S. Pansini 5, 80131, Naples, Italy.
| | - Brunella Capaldo
- Department of Clinical Medicine and Surgery, Federico II University, Naples, Italy.
| | - Margherita Ruoppolo
- Department of Molecular Medicine and Medical Biotechnology, Federico II University, Naples, Italy.
- CEINGE-Biotecnologie Avanzate s.c.ar.l., Naples, Italy.
| | - Aurora Daniele
- CEINGE-Biotecnologie Avanzate s.c.ar.l., Naples, Italy.
- Dipartimento di Scienze e Tecnologie Ambientali Biologiche Farmaceutiche, Seconda Università degli Studi di Napoli, Caserta, Italy.
| | - Giuseppe Bonapace
- Department of Pediatrics, Magna Graecia University, Catanzaro, Italy.
| | - Pietro Strisciuglio
- Department of Translational Medicine-Section of Pediatrics, Federico II University, Via S. Pansini 5, 80131, Naples, Italy.
| | - Giancarlo Parenti
- Department of Translational Medicine-Section of Pediatrics, Federico II University, Via S. Pansini 5, 80131, Naples, Italy.
| | - Generoso Andria
- Department of Translational Medicine-Section of Pediatrics, Federico II University, Via S. Pansini 5, 80131, Naples, Italy.
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Setoodeh A, Yarali B, Rabbani A, Khatami S, Shams S. Tetrahydrobiopterin responsiveness in a series of 53 cases of phenylketonuria and hyperphenylalaninemia in Iran. Mol Genet Metab Rep 2015. [PMID: 28649530 PMCID: PMC5471163 DOI: 10.1016/j.ymgmr.2015.01.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
To determine the prevalence of 6R-Tetrahydrobiopterin (BH4) responsive phenylketonuria (PKU) in 53 cases of patients with various classification of hyperphenylalaninemia and PKU Excluding the BH4 deficient type referring to children's medical center in Iran (phenylalanine 360–2420 μmol/L), the single dose of 20 mg/kg (Kuvan®) and duration of 24 h was used. Results Among the 4 different categories of mild hyperphenylalaninemia requiring treatment, mild, moderate and classic PKU, the BH4 responders were 90%, 35.7%, 5.6% and 0% respectively after 24 h. Conclusion BH4 responsiveness is more prevalent in mild hyperphenylalaninemia and mild PKU patients in Iran.
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Affiliation(s)
- Aria Setoodeh
- Division of Pediatric Endocrinology, Children's Medical Center, Tehran, Iran
| | - Bahram Yarali
- Division of Pediatric Neurology, Children's Medical Center, Tehran, Iran
| | - Ali Rabbani
- Growth and Development Center, Children's Medical Center, Tehran, Iran
| | | | - Sedigheh Shams
- Division of Pathology, Children's Medical Center, Tehran, Iran
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New Strategies for the Treatment of Phenylketonuria (PKU). Metabolites 2014; 4:1007-17. [PMID: 25375236 PMCID: PMC4279156 DOI: 10.3390/metabo4041007] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 10/27/2014] [Accepted: 10/30/2014] [Indexed: 12/19/2022] Open
Abstract
Phenylketonuria (PKU) was the first inherited metabolic disease in which dietary treatment was found to prevent the disease's clinical features. Treatment of phenylketonuria remains difficult due to progressive decrease in adherence to diet and the presence of neurocognitive defects despite therapy. This review aims to summarize the current literature on new treatment strategies. Additions to treatment include new, more palatable foods based on glycomacropeptide that contains very limited amount of aromatic amino acids, the administration of large neutral amino acids to prevent phenylalanine entry into the brain or tetrahydropterina cofactor capable of increasing residual activity of phenylalanine hydroxylase. Moreover, human trials have recently been performed with subcutaneous administration of phenylalanine ammonia-lyase, and further efforts are underway to develop an oral therapy containing phenylanine ammonia-lyase. Gene therapy also seems to be a promising approach in the near future.
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Picker JD, Walsh CA. New innovations: therapeutic opportunities for intellectual disabilities. Ann Neurol 2013; 74:382-90. [PMID: 24038210 DOI: 10.1002/ana.24002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 07/01/2013] [Accepted: 07/29/2013] [Indexed: 12/25/2022]
Abstract
Intellectual disability is common and is associated with significant morbidity. Until the latter half of the 20th century, there were no efficacious treatments. Following initial breakthroughs associated with newborn screening and metabolic corrections, little progress was made until recently. With improved understanding of genetic and cellular mechanisms, novel treatment options are beginning to appear for a number of specific conditions. Fragile X and tuberous sclerosis offer paradigms for the development of targeted therapeutics, but advances in understanding of other disorders such as Down syndrome and Rett syndrome, for example, are also resulting in promising treatment directions. In addition, better understanding of the underlying neurobiology is leading to novel developments in enzyme replacement for storage disorders and adjunctive therapies for metabolic disorders, as well as potentially more generalizable approaches that target dysfunctional cell regulation via RNA and chromatin. Physiologic therapies, including deep brain stimulation and transcranial magnetic stimulation, offer yet another direction to enhance cognitive functioning. Current options and evolving opportunities for the intellectually disabled are reviewed and exemplified.
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Affiliation(s)
- Jonathan D Picker
- Division of Genetics, Boston Children's Hospital, and Howard Hughes Medical Institute, Boston, MA; Departments of Pediatrics and Neurology,, Harvard Medical School, Boston, MA
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Pecce R, Scolamiero E, Ingenito L, Parenti G, Ruoppolo M. Optimization of an HPLC method for phenylalanine and tyrosine quantization in dried blood spot. Clin Biochem 2013; 46:1892-5. [DOI: 10.1016/j.clinbiochem.2013.08.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 08/28/2013] [Accepted: 08/30/2013] [Indexed: 12/11/2022]
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