1
|
Bose S, Mandal S, Khan R, Maji HS, Ashique S. Current Landscape on Development of Phenylalanine and Toxicity of its Metabolites - A Review. Curr Drug Saf 2024; 19:208-217. [PMID: 36999718 DOI: 10.2174/1574886318666230331112800] [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: 09/26/2022] [Revised: 02/19/2023] [Accepted: 02/22/2023] [Indexed: 04/01/2023]
Abstract
Phenylalanine, an essential amino acid, is the "building block" of protein. It has a tremendous role in different aspects of metabolic events. The tyrosine pathway is the prime one and is typically used to degrade dietary phenylalanine. Phenylalanine exceeds its limit in bodily fluids and the brain when the enzyme, phenylalanine decarboxylase, phenylalanine transaminase, phenylalanine hydroxylase (PAH) or its cofactor tetrahydrobiopterin (BH4) is deficient causes phenylketonuria, schizophrenia, attentiondeficit/ hyperactivity disorder and another neuronal effect. Tyrosine, an amino acid necessary for synthesizing the pigments in melanin, is produced by its primary metabolic pathway. Deficiency/abnormality in metabolic enzymes responsible for the catabolism pathway of Phenylalanine causes an accumulation of the active intermediate metabolite, resulting in several abnormalities, such as developmental delay, tyrosinemias, alkaptonuria, albinism, hypotension and several other undesirable conditions. Dietary restriction of the amino acid(s) can be a therapeutic approach to avoid such undesirable conditions when the level of metabolic enzyme is unpredictable. After properly identifying the enzymatic level, specific pathophysiological conditions can be managed more efficiently.
Collapse
Affiliation(s)
- Samrat Bose
- Division of Pharmacology, Guru Nanak Institute of Pharmaceutical Science and Technology, 157/F, Nilgunj Road, Kolkata, 700114, West Bengal, India
| | - Shirsendu Mandal
- Division of Pharmacology, Guru Nanak Institute of Pharmaceutical Science and Technology, 157/F, Nilgunj Road, Kolkata, 700114, West Bengal, India
| | - Rajesh Khan
- Division of Pharmacology, Guru Nanak Institute of Pharmaceutical Science and Technology, 157/F, Nilgunj Road, Kolkata, 700114, West Bengal, India
| | - Himangshu Sekhar Maji
- Division of Pharmaceutical Technology, JIS University, 81, Nilgunj Road, Agarpara, Kolkata, 700109, West Bengal, India
| | - Sumel Ashique
- Department of Pharmaceutics, Bharat Institute of Technology (BIT), School of Pharmacy, Meerut, 250103, UP, India
| |
Collapse
|
2
|
Vos EN, Demirbas D, Mangel M, Gozalbo MER, Levy HL, Berry GT. The treatment of biochemical genetic diseases: From substrate reduction to nucleic acid therapies. Mol Genet Metab 2023; 140:107693. [PMID: 37716025 DOI: 10.1016/j.ymgme.2023.107693] [Citation(s) in RCA: 1] [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: 07/07/2023] [Revised: 08/29/2023] [Accepted: 08/29/2023] [Indexed: 09/18/2023]
Abstract
Newborn screening (NBS) began a revolution in the management of biochemical genetic diseases, greatly increasing the number of patients for whom dietary therapy would be beneficial in preventing complications in phenylketonuria as well as in a few similar disorders. The advent of next generation sequencing and expansion of NBS have markedly increased the number of biochemical genetic diseases as well as the number of patients identified each year. With the avalanche of new and proposed therapies, a second wave of options for the treatment of biochemical genetic disorders has emerged. These therapies range from simple substrate reduction to enzyme replacement, and now ex vivo gene therapy with autologous cell transplantation. In some instances, it may be optimal to introduce nucleic acid therapy during the prenatal period to avoid fetopathy. However, as with any new therapy, complications may occur. It is important for physicians and other caregivers, along with ethicists, to determine what new therapies might be beneficial to the patient, and which therapies have to be avoided for those individuals who have less severe problems and for which standard treatments are available. The purpose of this review is to discuss the "Standard" treatment plans that have been in place for many years and to identify the newest and upcoming therapies, to assist the physician and other healthcare workers in making the right decisions regarding the initiation of both the "Standard" and new therapies. We have utilized several diseases to illustrate the applications of these different modalities and discussed for which disorders they may be suitable. The future is bright, but optimal care of the patient, including and especially the newborn infant, requires a deep knowledge of the disease process and careful consideration of the necessary treatment plan, not just based on the different genetic defects but also with regards to different variants within a gene itself.
Collapse
Affiliation(s)
- E Naomi Vos
- Division of Genetics & Genomics, Boston Children's Hospital; and Department of Pediatrics, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, United States of America; Manton Center for Orphan Disease Research, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, United States of America.
| | - Didem Demirbas
- Division of Genetics & Genomics, Boston Children's Hospital; and Department of Pediatrics, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, United States of America; Manton Center for Orphan Disease Research, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, United States of America.
| | - Matthew Mangel
- Division of Genetics & Genomics, Boston Children's Hospital; and Department of Pediatrics, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, United States of America.
| | - M Estela Rubio Gozalbo
- Department of Pediatrics and Clinical Genetics, Maastricht University Medical Centre+, P. Debyelaan 25, 6229 HX Maastricht, the Netherlands; GROW, Maastricht University, Minderbroedersberg 4-6, 6211 LK Maastricht, the Netherlands; MetabERN: European Reference Network for Hereditary Metabolic Disorders, Udine, Italy; UMD: United for Metabolic Diseases Member, Amsterdam, the Netherlands.
| | - Harvey L Levy
- Division of Genetics & Genomics, Boston Children's Hospital; and Department of Pediatrics, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, United States of America.
| | - Gerard T Berry
- Division of Genetics & Genomics, Boston Children's Hospital; and Department of Pediatrics, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, United States of America; Manton Center for Orphan Disease Research, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, United States of America.
| |
Collapse
|
3
|
Adams AD, Fiesco-Roa MÓ, Wong L, Jenkins GP, Malinowski J, Demarest OM, Rothberg PG, Hobert JA. Phenylalanine hydroxylase deficiency treatment and management: A systematic evidence review of the American College of Medical Genetics and Genomics (ACMG). Genet Med 2023; 25:100358. [PMID: 37470789 DOI: 10.1016/j.gim.2022.12.005] [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: 12/05/2022] [Revised: 12/08/2022] [Accepted: 12/08/2022] [Indexed: 07/21/2023] Open
Abstract
PURPOSE Elevated serum phenylalanine (Phe) levels due to biallelic pathogenic variants in phenylalanine hydroxylase (PAH) may cause neurodevelopmental disorders or birth defects from maternal phenylketonuria. New Phe reduction treatments have been approved in the last decade, but uncertainty on the optimal lifespan goal Phe levels for patients with PAH deficiency remains. METHODS We searched Medline and Embase for evidence of treatment concerning PAH deficiency up to September 28, 2021. Risk of bias was evaluated based on study design. Random-effects meta-analyses were performed to compare IQ, gestational outcomes, and offspring outcomes based on Phe ≤ 360 μmol/L vs > 360 μmol/L and reported as odds ratio and 95% CI. Remaining results were narratively synthesized. RESULTS A total of 350 studies were included. Risk of bias was moderate. Lower Phe was consistently associated with better outcomes. Achieving Phe ≤ 360 μmol/L before conception substantially lowered the risk of negative effect to offspring in pregnant individuals (odds ratio = 0.07, 95% CI = 0.04-0.14; P < .0001). Adverse events due to pharmacologic treatment were common, but medication reduced Phe levels, enabling dietary liberalization. CONCLUSIONS Reduction of Phe levels to ≤360 μmol/L through diet or medication represents effective interventions to treat PAH deficiency.
Collapse
Affiliation(s)
- April D Adams
- Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, TX; Division of Maternal-Fetal Medicine, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Moisés Ó Fiesco-Roa
- Programa de Maestría y Doctorado en Ciencias Médicas, Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico; Laboratorio de Citogenética, Instituto Nacional de Pediatría, Mexico City, Mexico
| | | | | | | | | | - Paul G Rothberg
- Department of Pathology & Laboratory Medicine, University of Rochester Medical Center, Rochester, NY
| | - Judith A Hobert
- University of Utah School of Medicine, Salt Lake City, UT; ARUP Laboratories, Salt Lake City, UT
| |
Collapse
|
4
|
Elhawary NA, AlJahdali IA, Abumansour IS, Elhawary EN, Gaboon N, Dandini M, Madkhali A, Alosaimi W, Alzahrani A, Aljohani F, Melibary EM, Kensara OA. Genetic etiology and clinical challenges of phenylketonuria. Hum Genomics 2022; 16:22. [PMID: 35854334 PMCID: PMC9295449 DOI: 10.1186/s40246-022-00398-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 07/08/2022] [Indexed: 02/08/2023] Open
Abstract
This review discusses the epidemiology, pathophysiology, genetic etiology, and management of phenylketonuria (PKU). PKU, an autosomal recessive disease, is an inborn error of phenylalanine (Phe) metabolism caused by pathogenic variants in the phenylalanine hydroxylase (PAH) gene. The prevalence of PKU varies widely among ethnicities and geographic regions, affecting approximately 1 in 24,000 individuals worldwide. Deficiency in the PAH enzyme or, in rare cases, the cofactor tetrahydrobiopterin results in high blood Phe concentrations, causing brain dysfunction. Untreated PKU, also known as PAH deficiency, results in severe and irreversible intellectual disability, epilepsy, behavioral disorders, and clinical features such as acquired microcephaly, seizures, psychological signs, and generalized hypopigmentation of skin (including hair and eyes). Severe phenotypes are classic PKU, and less severe forms of PAH deficiency are moderate PKU, mild PKU, mild hyperphenylalaninaemia (HPA), or benign HPA. Early diagnosis and intervention must start shortly after birth to prevent major cognitive and neurological effects. Dietary treatment, including natural protein restriction and Phe-free supplements, must be used to maintain blood Phe concentrations of 120-360 μmol/L throughout the life span. Additional treatments include the casein glycomacropeptide (GMP), which contains very limited aromatic amino acids and may improve immunological function, and large neutral amino acid (LNAA) supplementation to prevent plasma Phe transport into the brain. The synthetic BH4 analog, sapropterin hydrochloride (i.e., Kuvan®, BioMarin), is another potential treatment that activates residual PAH, thus decreasing Phe concentrations in the blood of PKU patients. Moreover, daily subcutaneous injection of pegylated Phe ammonia-lyase (i.e., pegvaliase; PALYNZIQ®, BioMarin) has promised gene therapy in recent clinical trials, and mRNA approaches are also being studied.
Collapse
Affiliation(s)
- Nasser A. Elhawary
- Department of Medical Genetics, College of Medicine, Umm Al-Qura University, P.O. Box 57543, Mecca, 21955 Saudi Arabia
| | - Imad A. AlJahdali
- Department of Community Medicine, College of Medicine, Umm Al-Qura University, P.O. Box 57543, Mecca, 21955 Saudi Arabia
| | - Iman S. Abumansour
- Department of Medical Genetics, College of Medicine, Umm Al-Qura University, P.O. Box 57543, Mecca, 21955 Saudi Arabia
| | - Ezzeldin N. Elhawary
- Faculty of Medicine, MS Genomic Medicine Program, University of Southampton, Southampton General Hospital, Southampton, UK
| | - Nagwa Gaboon
- Department of Clinical Genetics, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Mohammed Dandini
- Department of Laboratory and Blood Bank, Maternity and Children Hospital, Mecca, Saudi Arabia
| | - Abdulelah Madkhali
- Department of Pathology and Laboratory Medicine, King Abdulaziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia
| | - Wafaa Alosaimi
- Department of Hematology, Maternity and Children Hospital, Mecca, Saudi Arabia
| | - Abdulmajeed Alzahrani
- Department of Laboratory and Blood Bank at Maternity and Children Hospital, Mecca, Saudi Arabia
| | - Fawzia Aljohani
- Department of Pediatric Clinics, Maternity and Children Hospital, King Salman Medical City, Madinah, Saudi Arabia
| | - Ehab M. Melibary
- Department of Medical Genetics, College of Medicine, Umm Al-Qura University, P.O. Box 57543, Mecca, 21955 Saudi Arabia
| | - Osama A. Kensara
- Department of Clinical Nutrition, Faculty of Applied Medical Sciences, Umm Al-Qura University, Jeddah, Saudi Arabia
- Department of Biochemistry, Batterjee Medical College, Jeddah, Saudi Arabia
| |
Collapse
|
5
|
Ahring KK, Dagnæs-Hansen F, Brüel A, Christensen M, Jensen E, Jensen TG, Johannsen M, Johansen KS, Lund AM, Madsen JG, Brøndum-Nielsen K, Pedersen M, Sørensen LK, Kjolby M, Møller LB. The effect of casein glycomacropeptide versus free synthetic amino acids for early treatment of phenylketonuria in a mice model. PLoS One 2022; 17:e0261150. [PMID: 35015767 PMCID: PMC8751992 DOI: 10.1371/journal.pone.0261150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 11/24/2021] [Indexed: 11/26/2022] Open
Abstract
Introduction Management of phenylketonuria (PKU) is mainly achieved through dietary control with limited intake of phenylalanine (Phe) from food, supplemented with low protein (LP) food and a mixture of free synthetic (FS) amino acids (AA) (FSAA). Casein glycomacropeptide (CGMP) is a natural peptide released in whey during cheese making by the action of the enzyme chymosin. Because CGMP in its pure form does not contain Phe, it is nutritionally suitable as a supplement in the diet for PKU when enriched with specific AAs. Lacprodan® CGMP-20 (= CGMP) used in this study contained only trace amounts of Phe due to minor presence of other proteins/peptides. Objective The aims were to address the following questions in a classical PKU mouse model: Study 1, off diet: Can pure CGMP or CGMP supplemented with Large Neutral Amino Acids (LNAA) as a supplement to normal diet significantly lower the content of Phe in the brain compared to a control group on normal diet, and does supplementation of selected LNAA results in significant lower brain Phe level?. Study 2, on diet: Does a combination of CGMP, essential (non-Phe) EAAs and LP diet, provide similar plasma and brain Phe levels, growth and behavioral skills as a formula which alone consist of FSAA, with a similar composition?. Material and methods 45 female mice homozygous for the Pahenu2 mutation were treated for 12 weeks in five different groups; G1(N-CGMP), fed on Normal (N) casein diet (75%) in combination with CGMP (25%); G2 (N-CGMP-LNAA), fed on Normal (N) casein diet (75%) in combination with CGMP (19,7%) and selected LNAA (5,3% Leu, Tyr and Trp); G3 (N), fed on normal casein diet (100%); G4 (CGMP-EAA-LP), fed on CGMP (70,4%) in combination with essential AA (19,6%) and LP diet; G5 (FSAA-LP), fed on FSAA (100%) and LP diet. The following parameters were measured during the treatment period: Plasma AA profiles including Phe and Tyr, growth, food and water intake and number of teeth cut. At the end of the treatment period, a body scan (fat and lean body mass) and a behavioral test (Barnes Maze) were performed. Finally, the brains were examined for content of Phe, Tyr, Trp, dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), serotonin (5-HT) and 5-hydroxyindole-acetic acid (5-HIAA), and the bone density and bone mineral content were determined by dual-energy x-ray absorptiometry. Results Study 1: Mice off diet supplemented with CGMP (G1 (N-CGMP)) or supplemented with CGMP in combination with LNAA (G2 (N-CGMP-LNAA)) had significantly lower Phe in plasma and in the brain compared to mice fed only casein (G3 (N)). Extra LNAA (Tyr, Trp and Leu) to CGMP did not have any significant impact on Phe levels in the plasma and brain, but an increase in serotonin was measured in the brain of G2 mice compared to G1. Study 2: PKU mice fed with mixture of CGMP and EAA as supplement to LP diet (G4 (CGMP-EAA-LP)) demonstrated lower plasma-Phe levels but similar brain- Phe levels and growth as mice fed on an almost identical combination of FSAA (G5 (FSAA-LP)). Conclusion CGMP can be a relevant supplement for the treatment of PKU.
Collapse
Affiliation(s)
- Kirsten K. Ahring
- Departments of Paediatrics and Clinical Genetics, PKU Clinic, Kennedy Center, Copenhagen University Hospital, Rigshospitalet, Denmark
- * E-mail:
| | | | - Annemarie Brüel
- Department of Biomedicine, Health, Aarhus University, Aarhus, Denmark
| | - Mette Christensen
- Departments of Paediatrics and Clinical Genetics, Centre for Inherited Metabolic Diseases, Copenhagen University Hospital, Rigshospitalet, Denmark
| | - Erik Jensen
- Arla Foods Ingredients Group P/S, Viby J, Denmark
| | - Thomas G. Jensen
- Department of Biomedicine, Health, Aarhus University, Aarhus, Denmark
| | - Mogens Johannsen
- Department of Forensic Medicine, Aarhus University, Skejby, Aarhus, Denmark
| | - Karen S. Johansen
- Department of Biomedicine, Health, Aarhus University, Aarhus, Denmark
| | - Allan M. Lund
- Departments of Paediatrics and Clinical Genetics, Centre for Inherited Metabolic Diseases, Copenhagen University Hospital, Rigshospitalet, Denmark
| | - Jesper G. Madsen
- Department of Biomedicine, Health, Aarhus University, Aarhus, Denmark
| | - Karen Brøndum-Nielsen
- Departments of Paediatrics and Clinical Genetics, PKU Clinic, Kennedy Center, Copenhagen University Hospital, Rigshospitalet, Denmark
| | - Michael Pedersen
- Comparative Medicine Lab, Aarhus University Hospital, Aarhus, Denmark
| | | | - Mads Kjolby
- Department of Biomedicine, Health, Aarhus University, Aarhus, Denmark
- Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Pharmacology, Aarhus University Hospital, Aarhus, Denmark
| | - Lisbeth B. Møller
- Department of Clinical Genetics, Kennedy Center, Copenhagen University Hospital, Rigshospitalet, Denmark
| |
Collapse
|
6
|
van Vliet D, van der Goot E, van Ginkel WG, van Faassen HJR, de Blaauw P, Kema IP, Heiner-Fokkema MR, van der Zee EA, van Spronsen FJ. The increasing importance of LNAA supplementation in phenylketonuria at higher plasma phenylalanine concentrations. Mol Genet Metab 2022; 135:27-34. [PMID: 34974973 DOI: 10.1016/j.ymgme.2021.11.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 10/01/2021] [Accepted: 11/04/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND Large neutral amino acid (LNAA) treatment has been suggested as alternative to the burdensome severe phenylalanine-restricted diet. While its working mechanisms and optimal composition have recently been further elucidated, the question whether LNAA treatment requires the natural protein-restricted diet, has still remained. OBJECTIVE Firstly, to determine whether an additional liberalized natural protein-restricted diet could further improve brain amino acid and monoamine concentrations in phenylketonuria mice on LNAA treatment. Secondly, to compare the effect between LNAA treatment (without natural protein) restriction and different levels of a phenylalanine-restricted diet (without LNAA treatment) on brain amino acid and monoamine concentrations in phenylketonuria mice. DESIGN BTBR Pah-enu2 mice were divided into two experimental groups that received LNAA treatment with either an unrestricted or semi phenylalanine-restricted diet. Control groups included Pah-enu2 mice on the AIN-93 M diet, a severe or semi phenylalanine-restricted diet without LNAA treatment, and wild-type mice receiving the AIN-93 M diet. After ten weeks, brain and plasma samples were collected to measure amino acid profiles and brain monoaminergic neurotransmitter concentrations. RESULTS Adding a semi phenylalanine-restricted diet to LNAA treatment resulted in lower plasma phenylalanine but comparable brain amino acid and monoamine concentrations as compared to LNAA treatment (without phenylalanine restriction). LNAA treatment (without phenylalanine restriction) resulted in comparable brain monoamine but higher brain phenylalanine concentrations compared to the severe phenylalanine-restricted diet, and significantly higher brain monoamine but comparable phenylalanine concentrations as compared to the semi phenylalanine-restricted diet. CONCLUSIONS Present results in PKU mice suggest that LNAA treatment in PKU patients does not need the phenylalanine-restricted diet. In PKU mice, LNAA treatment (without phenylalanine restriction) was comparable to a severe phenylalanine-restricted diet with respect to brain monoamine concentrations, notwithstanding the higher plasma and brain phenylalanine concentrations, and resulted in comparable brain phenylalanine concentrations as on a semi phenylalanine-restricted diet.
Collapse
Affiliation(s)
- D van Vliet
- University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Groningen, the Netherlands
| | - E van der Goot
- University of Groningen, Groningen Institute for Evolutionary Life Sciences, Department of Molecular Neurobiology, Groningen, the Netherlands
| | - W G van Ginkel
- University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Groningen, the Netherlands
| | - H J R van Faassen
- University of Groningen, University Medical Center Groningen, Department of Laboratory Medicine, Groningen, the Netherlands
| | - P de Blaauw
- University of Groningen, University Medical Center Groningen, Department of Laboratory Medicine, Groningen, the Netherlands
| | - I P Kema
- University of Groningen, University Medical Center Groningen, Department of Laboratory Medicine, Groningen, the Netherlands
| | - M R Heiner-Fokkema
- University of Groningen, University Medical Center Groningen, Department of Laboratory Medicine, Groningen, the Netherlands
| | - E A van der Zee
- University of Groningen, Groningen Institute for Evolutionary Life Sciences, Department of Molecular Neurobiology, Groningen, the Netherlands
| | - F J van Spronsen
- University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Groningen, the Netherlands.
| |
Collapse
|
7
|
Scala I, Concolino D, Nastasi A, Esposito G, Crisci D, Sestito S, Ferraro S, Albano L, Ruoppolo M, Parenti G, Strisciuglio P. Beneficial Effects of Slow-Release Large Neutral Amino Acids after a Phenylalanine Oral Load in Patients with Phenylketonuria. Nutrients 2021; 13:nu13114012. [PMID: 34836270 PMCID: PMC8618154 DOI: 10.3390/nu13114012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 10/29/2021] [Accepted: 11/05/2021] [Indexed: 11/16/2022] Open
Abstract
The mainstay of phenylketonuria treatment is a low protein diet, supplemented with phenylalanine (Phe)-free protein substitutes and micronutrients. Adhering to this diet is challenging, and even patients with good metabolic control who follow the dietary prescriptions in everyday life ignore the recommendations occasionally. The present study explores the ability of slow-release large neutral amino acids (srLNAAs) to prevent Phe increase following a Phe dietary load. Fourteen phenylketonuric patients aged ≥13 years were enrolled in a 6-week protocol. Oral acute Phe loads of 250 and 500 mg were added to the evening meal together with srLNAAs (0.5 gr/kg). Phe and tyrosine were dosed before dinner, 2h-after dinner, and after the overnight fast. After oral Phe loads, mean plasma Phe remained stable and below 600 µmol/L. No Phe peaks were registered. Tyrosine levels significantly increased, and Phe/Tyrosine ratio decreased. No adverse events were registered. In conclusion, a single oral administration of srLNAAs at the dose of 0.5 gr/kg is effective in maintaining stable plasma Phe during acute oral loads with Phe-containing food and may be added to the dietetic scheme in situations in which patients with generally good adherence to diet foresee a higher than prescribed Phe intake due to their commitments.
Collapse
Affiliation(s)
- Iris Scala
- Department of Maternal and Child Health, Federico II University Hospital, 80131 Naples, Italy
- Correspondence: ; Tel.: +39-081-7463348; +39-081-7463769
| | - Daniela Concolino
- Pediatric Unit, Department of Health Sciences, Magna Graecia University of Catanzaro, 88100 Catanzaro, Italy; (D.C.); (S.S.); (S.F.)
| | - Anna Nastasi
- Physiology Nutrition Unit, Department of Clinical Medicine and Surgery, Federico II University, 80131 Naples, Italy;
| | - Giulia Esposito
- Department of Translational Medical Science, Section of Pediatrics, Federico II University, 80131 Naples, Italy; (G.E.); (G.P.); (P.S.)
| | - Daniela Crisci
- CEINGE Biotecnologie Avanzate Scarl, 80131 Naples, Italy; (D.C.); (L.A.); (M.R.)
| | - Simona Sestito
- Pediatric Unit, Department of Health Sciences, Magna Graecia University of Catanzaro, 88100 Catanzaro, Italy; (D.C.); (S.S.); (S.F.)
| | - Stefania Ferraro
- Pediatric Unit, Department of Health Sciences, Magna Graecia University of Catanzaro, 88100 Catanzaro, Italy; (D.C.); (S.S.); (S.F.)
| | - Lucia Albano
- CEINGE Biotecnologie Avanzate Scarl, 80131 Naples, Italy; (D.C.); (L.A.); (M.R.)
| | - Margherita Ruoppolo
- CEINGE Biotecnologie Avanzate Scarl, 80131 Naples, Italy; (D.C.); (L.A.); (M.R.)
- Department of Molecular Medicine and Medical Biotechnologies, Federico II University, 80131 Naples, Italy
| | - Giancarlo Parenti
- Department of Translational Medical Science, Section of Pediatrics, Federico II University, 80131 Naples, Italy; (G.E.); (G.P.); (P.S.)
- Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy
| | - Pietro Strisciuglio
- Department of Translational Medical Science, Section of Pediatrics, Federico II University, 80131 Naples, Italy; (G.E.); (G.P.); (P.S.)
| |
Collapse
|
8
|
Abstract
Phenylketonuria (PKU; also known as phenylalanine hydroxylase (PAH) deficiency) is an autosomal recessive disorder of phenylalanine metabolism, in which especially high phenylalanine concentrations cause brain dysfunction. If untreated, this brain dysfunction results in severe intellectual disability, epilepsy and behavioural problems. The prevalence varies worldwide, with an average of about 1:10,000 newborns. Early diagnosis is based on newborn screening, and if treatment is started early and continued, intelligence is within normal limits with, on average, some suboptimal neurocognitive function. Dietary restriction of phenylalanine has been the mainstay of treatment for over 60 years and has been highly successful, although outcomes are still suboptimal and patients can find the treatment difficult to adhere to. Pharmacological treatments are available, such as tetrahydrobiopterin, which is effective in only a minority of patients (usually those with milder PKU), and pegylated phenylalanine ammonia lyase, which requires daily subcutaneous injections and causes adverse immune responses. Given the drawbacks of these approaches, other treatments are in development, such as mRNA and gene therapy. Even though PAH deficiency is the most common defect of amino acid metabolism in humans, brain dysfunction in individuals with PKU is still not well understood and further research is needed to facilitate development of pathophysiology-driven treatments.
Collapse
Affiliation(s)
- Francjan J van Spronsen
- Beatrix Children's Hospital, University Medical Centre Groningen, University of Groningen, Groningen, Netherlands.
| | - Nenad Blau
- University Children's Hospital in Zurich, Zurich, Switzerland
| | - Cary Harding
- Department of Molecular and Medical Genetics and Department of Pediatrics, Oregon Health & Science University, Oregon, USA
| | | | - Nicola Longo
- Department of Pediatrics, University of Utah, Salt Lake City, Utah, USA
| | - Annet M Bosch
- University of Amsterdam, Department of Pediatrics, Division of Metabolic Disorders, Emma Children's Hospital, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| |
Collapse
|
9
|
The Adult Phenylketonuria (PKU) Gut Microbiome. Microorganisms 2021; 9:microorganisms9030530. [PMID: 33806544 PMCID: PMC8001843 DOI: 10.3390/microorganisms9030530] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 02/25/2021] [Accepted: 02/26/2021] [Indexed: 12/16/2022] Open
Abstract
Phenylketonuria (PKU) is an inborn error of phenylalanine metabolism primarily treated through a phenylalanine-restrictive diet that is frequently supplemented with an amino acid formula to maintain proper nutrition. Little is known of the effects of these dietary interventions on the gut microbiome of PKU patients, particularly in adults. In this study, we sequenced the V4 region of the 16S rRNA gene from stool samples collected from adults with PKU (n = 11) and non-PKU controls (n = 21). Gut bacterial communities were characterized through measurements of diversity and taxa abundance. Additionally, metabolic imputation was performed based on detected bacteria. Gut community diversity was lower in PKU individuals, though this effect was only statistically suggestive. A total of 65 genera across 5 phyla were statistically differentially abundant between PKU and control samples (p < 0.001). Additionally, we identified six metabolic pathways that differed between groups (p < 0.05), with four enriched in PKU samples and two in controls. While the child PKU gut microbiome has been previously investigated, this is the first study to explore the gut microbiome of adult PKU patients. We find that microbial diversity in PKU children differs from PKU adults and highlights the need for further studies to understand the effects of dietary restrictions.
Collapse
|
10
|
Manta-Vogli PD, Dotsikas Y, Loukas YL, Schulpis KH. The phenylketonuria patient: A recent dietetic therapeutic approach. Nutr Neurosci 2020; 23:628-639. [PMID: 30359206 DOI: 10.1080/1028415x.2018.1538196] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Phenylalanine hydroxylase (PAH) deficiency, commonly named phenylketonuria (PKU) is a disorder of phenylalanine (Phe) metabolism inherited with an autosomal recessive trait. It is characterized by high blood and cerebral Phe levels, resulting in intellectual disabilities, seizures, etc. Early diagnosis and treatment of the patients prevent major neuro-cognitive deficits. Treatment consists of a lifelong restriction of Phe intake, combined with the supplementation of special medical foods, such as Amino Acid medical food (AA-mf), enriched in tyrosine (Tyr) and other amino acids and nutrients to avoid nutritional deficits. Developmental and neurocognitive outcomes for patients, however, remain suboptimal, especially when adherence to the demanding diet is poor. Additions to treatment include new, more palatable foods, based on Glycomacropeptide that contains limited amounts of Phe, the administration of large neutral amino acids to prevent phenylalanine entry into the brain and tetrahydrobiopterin cofactor capable of increasing residual PAH activity. Moreover, further efforts are underway to develop an oral therapy containing phenylalanine ammonia-lyase. Nutritional support of PKU future mothers (maternal PKU) is also discussed. This review aims to summarize the current literature on new PKU treatment strategies.
Collapse
Affiliation(s)
- Penelope D Manta-Vogli
- Department of Clinical Nutrition & Dietetics Agia Sofia Children's Hospital, Athens, Greece
| | - Yannis Dotsikas
- Department of Pharmacy, Laboratory of Pharm. Analysis, National and Kapodestrian University of Athens, Panepistimiopolis Zographou, GR 157 71, Athens, Greece
| | - Yannis L Loukas
- Department of Pharmacy, Laboratory of Pharm. Analysis, National and Kapodestrian University of Athens, Panepistimiopolis Zographou, GR 157 71, Athens, Greece
| | | |
Collapse
|
11
|
Abstract
BACKGROUND Phenylketonuria is an inherited disease treated with dietary restriction of the amino acid phenylalanine. The diet is initiated in the neonatal period to prevent learning disability; however, it is restrictive and can be difficult to follow. Whether the diet can be relaxed or discontinued during adolescence or should be continued for life remains a controversial issue, which we aim to address in this review. This is an updated version of a previously published review. OBJECTIVES To assess the effects of a low-phenylalanine diet commenced early in life for people with phenylketonuria. To assess the possible effects of relaxation or termination of the diet on intelligence, neuropsychological outcomes and mortality, growth, nutritional status, eating behaviour and quality of life. SEARCH METHODS We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising references identified from comprehensive electronic database searches, handsearches of relevant journals and abstract books of conference proceedings. Most recent search of the Inborn Errors of Metabolism Trials Register: 30 April 2020. SELECTION CRITERIA All randomised or quasi-randomised controlled trials comparing a low-phenylalanine diet to relaxation or termination of dietary restrictions in people with phenylketonuria. DATA COLLECTION AND ANALYSIS Two authors independently assessed study eligibility and methodological quality, and subsequently extracted the data. MAIN RESULTS We included four studies in this review (251 participants), and found few significant differences between treatment and comparison groups for the outcomes of interest. Blood phenylalanine levels were significantly lower in participants with phenylketonuria following a low-phenylalanine diet compared to those on a less restricted diet, mean difference (MD) at three months -698.67 (95% confidence interval (CI) -869.44 to -527.89). Intelligence quotient was significantly higher in participants who continued the diet than in those who stopped the diet, MD after 12 months 5.00 (95% CI 0.40 to 9.60). However, these results came from a single study. AUTHORS' CONCLUSIONS The results of non-randomised studies have concluded that a low-phenylalanine diet is effective in reducing blood phenylalanine levels and improving intelligence quotient and neuropsychological outcomes. We were unable to find any randomised controlled studies that have assessed the effect of a low-phenylalanine diet versus no diet from diagnosis. In view of evidence from non-randomised studies, such a study would be unethical and it is recommended that low-phenylalanine diet should be commenced at the time of diagnosis. There is uncertainty about the precise level of phenylalanine restriction and when, if ever, the diet should be relaxed. This should be addressed by randomised controlled studies; however, no new studies are expected in this area so we do not plan to update this review.
Collapse
Affiliation(s)
- Elisabeth Jameson
- Willink Biochemical Genetics Unit, Manchester Centre for Genomic Medicine, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
| | - Tracey Remmington
- Department of Women's and Children's Health, University of Liverpool, Liverpool, UK
| |
Collapse
|
12
|
Burlina AP, Cazzorla C, Massa P, Loro C, Gueraldi D, Burlina AB. The Impact of a Slow-Release Large Neutral Amino Acids Supplement on Treatment Adherence in Adult Patients with Phenylketonuria. Nutrients 2020; 12:nu12072078. [PMID: 32674279 PMCID: PMC7400920 DOI: 10.3390/nu12072078] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 07/10/2020] [Accepted: 07/10/2020] [Indexed: 01/08/2023] Open
Abstract
The gold standard treatment for phenylketonuria (PKU) is a lifelong low-phenylalanine (Phe) diet supplemented with Phe-free protein substitutes. Adherence to therapy becomes difficult after childhood. Supplementing with large neutral amino acids (LNAAs) has been proposed as an alternative medication to Phe-free protein substitutes (i.e., amino acid mixtures). The aim of this study was to evaluate adherence to therapy and quality of life (QoL) in a cohort of sub-optimally controlled adult PKU patients treated with a new LNAA formulation. Twelve patients were enrolled in a 12-month-trial of slow-release LNAAs (1g/kg/day) plus a Phe-restricted diet. Medication adherence was measured with the Morisky Green Levine Medication Adherence Scale; the QoL was measured using the phenylketonuria-quality of life (PKU-QoL) questionnaire. Phe, tyrosine (Tyr) levels, and Phe/Tyr ratios were measured fortnightly. Before treatment, 3/12 patients self-reported a ‘medium’ adherence to medication and 9/12 reported a low adherence; 60% of patients reported a full adherence over the past four weeks. After 12 months of LNAA treatment, all patients self-reported a high adherence to medication, with 96% reporting a full adherence. Phe levels remained unchanged, while Tyr levels increased in most patients. The Phy/Tyr ratio decreased. All patients had a significant improvement in the QoL. LNAAs may give patients a further opportunity to improve medication adherence and, consequently, their QoL.
Collapse
Affiliation(s)
- Alessandro P. Burlina
- Neurological Unit, St. Bassiano Hospital, Via dei Lotti 40, 36061 Bassano del Grappa, Italy;
| | - Chiara Cazzorla
- Division of Inherited Metabolic Diseases, Department of Women and Children’s Health, University Hospital of Padova, Via Giustiniani 3, 35128 Padova, Italy; (C.C.); (P.M.); (C.L.); (D.G.)
| | - Pamela Massa
- Division of Inherited Metabolic Diseases, Department of Women and Children’s Health, University Hospital of Padova, Via Giustiniani 3, 35128 Padova, Italy; (C.C.); (P.M.); (C.L.); (D.G.)
| | - Christian Loro
- Division of Inherited Metabolic Diseases, Department of Women and Children’s Health, University Hospital of Padova, Via Giustiniani 3, 35128 Padova, Italy; (C.C.); (P.M.); (C.L.); (D.G.)
| | - Daniela Gueraldi
- Division of Inherited Metabolic Diseases, Department of Women and Children’s Health, University Hospital of Padova, Via Giustiniani 3, 35128 Padova, Italy; (C.C.); (P.M.); (C.L.); (D.G.)
| | - Alberto B. Burlina
- Division of Inherited Metabolic Diseases, Department of Women and Children’s Health, University Hospital of Padova, Via Giustiniani 3, 35128 Padova, Italy; (C.C.); (P.M.); (C.L.); (D.G.)
- Correspondence: ; Tel.: +39-049 8213569
| |
Collapse
|
13
|
Large Neutral Amino Acids (LNAAs) Supplementation Improves Neuropsychological Performances in Adult Patients with Phenylketonuria. Nutrients 2020; 12:nu12041092. [PMID: 32326614 PMCID: PMC7230959 DOI: 10.3390/nu12041092] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 03/29/2020] [Accepted: 04/10/2020] [Indexed: 11/17/2022] Open
Abstract
Phenylketonuria is an inborn error of phenylalanine (Phe) metabolism diagnosed by newborn screening and treated early with diet. Although diet prevents intellectual disability, patients often show impairment of executive functions, working memory, sustained attention, and cognitive flexibility. Large neutral amino acids (LNAAs) have been proposed as a dietary supplement for PKU adults. Few studies show that LNAAs may help in improving metabolic control as well as cognitive functions. In this study, 10 adult PKU patients with poor metabolic control were treated for 12 months with LNAAs (MovisCom, 0.8–1 g/kg/day) and underwent Phe and Tyrosine (Tyr) monitoring monthly. Neuropsychological assessment was performed at T0, T+3, and T+12 months by using the American Psychological General Well-Being Index, the Wisconsin Card Sorting Test, the Test of Attentional Performance, and the 9-Hole Peg Test. No change in plasma Phe levels was observed during LNAAs supplementation, while Tyr levels significantly improved during LNAAs supplementation (p = 0.03). Psychometric tests showed an improvement of distress and well-being rates, of executive functions, attention, and vigilance, whereas no difference was noted regarding hand dexterity. This study adds evidence of the advantage of LNAAs supplementation in improving cognitive functions and well-being in patients with PKU with poor metabolic control.
Collapse
|
14
|
Pugliese M, Tingley K, Chow A, Pallone N, Smith M, Rahman A, Chakraborty P, Geraghty MT, Irwin J, Tessier L, Nicholls SG, Offringa M, Butcher NJ, Iverson R, Clifford TJ, Stockler S, Hutton B, Paik K, Tao J, Skidmore B, Coyle D, Duddy K, Dyack S, Greenberg CR, Ghai SJ, Karp N, Korngut L, Kronick J, MacKenzie A, MacKenzie J, Maranda B, Mitchell JJ, Potter M, Prasad C, Schulze A, Sparkes R, Taljaard M, Trakadis Y, Walia J, Potter BK. Outcomes in pediatric studies of medium-chain acyl-coA dehydrogenase (MCAD) deficiency and phenylketonuria (PKU): a review. Orphanet J Rare Dis 2020; 15:12. [PMID: 31937333 PMCID: PMC6961328 DOI: 10.1186/s13023-019-1276-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 12/05/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Inherited metabolic diseases (IMDs) are a group of individually rare single-gene diseases. For many IMDs, there is a paucity of high-quality evidence that evaluates the effectiveness of clinical interventions. Clinical effectiveness trials of IMD interventions could be supported through the development of core outcome sets (COSs), a recommended minimum set of standardized, high-quality outcomes and associated outcome measurement instruments to be incorporated by all trials in an area of study. We began the process of establishing pediatric COSs for two IMDs, medium-chain acyl-CoA dehydrogenase (MCAD) deficiency and phenylketonuria (PKU), by reviewing published literature to describe outcomes reported by authors, identify heterogeneity in outcomes across studies, and assemble a candidate list of outcomes. METHODS We used a comprehensive search strategy to identify primary studies and guidelines relevant to children with MCAD deficiency and PKU, extracting study characteristics and outcome information from eligible studies including outcome measurement instruments for select outcomes. Informed by an established framework and a previously published pediatric COS, outcomes were grouped into five, mutually-exclusive, a priori core areas: growth and development, life impact, pathophysiological manifestations, resource use, and death. RESULTS For MCAD deficiency, we identified 83 outcomes from 52 articles. The most frequently represented core area was pathophysiological manifestations, with 33 outcomes reported in 29/52 articles (56%). Death was the most frequently reported outcome. One-third of outcomes were reported by a single study. The most diversely measured outcome was cognition and intelligence/IQ for which eight unique measurement instruments were reported among 14 articles. For PKU, we identified 97 outcomes from 343 articles. The most frequently represented core area was pathophysiological manifestations with 31 outcomes reported in 281/343 articles (82%). Phenylalanine concentration was the most frequently reported outcome. Sixteen percent of outcomes were reported by a single study. Similar to MCAD deficiency, the most diversely measured PKU outcome was cognition and intelligence/IQ with 39 different instruments reported among 82 articles. CONCLUSIONS Heterogeneity of reported outcomes and outcome measurement instruments across published studies for both MCAD deficiency and PKU highlights the need for COSs for these diseases, to promote the use of meaningful outcomes and facilitate comparisons across studies.
Collapse
Affiliation(s)
- Michael Pugliese
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Ontario, Canada
| | - Kylie Tingley
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Ontario, Canada
| | - Andrea Chow
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Ontario, Canada
| | | | - Maureen Smith
- Canadian Organization for Rare Disorders, Ottawa, Canada
| | - Alvi Rahman
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Ontario, Canada
| | - Pranesh Chakraborty
- Newborn Screening Ontario, Children's Hospital of Eastern Ontario, Ottawa, Canada
| | - Michael T Geraghty
- Division of Metabolics and Newborn Screening, Pediatrics, Children's Hospital of Eastern Ontario and University of Ottawa, Ottawa, Canada
| | - Julie Irwin
- Ambulatory Care, Children's Hospital of Eastern Ontario, Ottawa, Canada
| | - Laure Tessier
- Newborn Screening Ontario, Children's Hospital of Eastern Ontario, Ottawa, Canada
| | - Stuart G Nicholls
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Canada
| | - Martin Offringa
- Department of Pediatrics, University of Toronto, Toronto, Canada.,Child Health Evaluative Sciences, The Hospital for Sick Children Research Institute, Toronto, Canada
| | - Nancy J Butcher
- Child Health Evaluative Sciences, The Hospital for Sick Children Research Institute, Toronto, Canada
| | - Ryan Iverson
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Ontario, Canada
| | - Tammy J Clifford
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Ontario, Canada
| | - Sylvia Stockler
- Biochemical Diseases, BC Children's Hospital, Vancouver, Canada
| | - Brian Hutton
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Ontario, Canada
| | - Karen Paik
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Ontario, Canada
| | - Jessica Tao
- Faculty of Medicine, University of Ottawa, Ottawa, Canada
| | - Becky Skidmore
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Canada
| | - Doug Coyle
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Ontario, Canada
| | - Kathleen Duddy
- Biochemical Diseases, BC Children's Hospital, Vancouver, Canada
| | - Sarah Dyack
- Division of Medical Genetics, IWK Health Centre, Halifax, Canada
| | - Cheryl R Greenberg
- Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, Canada
| | - Shailly Jain Ghai
- Department of Medical Genetics, University of Alberta, Edmonton, Canada
| | - Natalya Karp
- Department of Pediatrics, Western University, London, Canada
| | - Lawrence Korngut
- Department of Clinical Neurosciences, University of Calgary, Calgary, Canada
| | - Jonathan Kronick
- Department of Pediatrics, University of Toronto, Toronto, Canada.,Clinical and Metabolic Genetics, The Hospital for Sick Children, Toronto, Canada
| | - Alex MacKenzie
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, Canada
| | | | - Bruno Maranda
- Department of Pediatrics, Université de Sherbrooke, Sherbrooke, Canada
| | - John J Mitchell
- Human Genetics and Pediatrics, McGill University, Montreal, Canada
| | - Murray Potter
- Pathology and Molecular Medicine, McMaster University, Hamilton, Canada
| | - Chitra Prasad
- Department of Pediatrics, Western University, London, Canada
| | - Andreas Schulze
- Department of Pediatrics, University of Toronto, Toronto, Canada
| | - Rebecca Sparkes
- Medical Genetics and Pediatrics, University of Calgary, Calgary, Canada
| | - Monica Taljaard
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Ontario, Canada.,Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Canada
| | - Yannis Trakadis
- Human Genetics and Medical Genetics, McGill University Health Centre, Montreal, Canada
| | - Jagdeep Walia
- Department of Pediatrics, Queen's University, Kingston, Canada
| | - Beth K Potter
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Ontario, Canada.
| | | |
Collapse
|
15
|
Romani C, Manti F, Nardecchia F, Valentini F, Fallarino N, Carducci C, De Leo S, MacDonald A, Palermo L, Leuzzi V. Adult cognitive outcomes in phenylketonuria: explaining causes of variability beyond average Phe levels. Orphanet J Rare Dis 2019; 14:273. [PMID: 31779649 PMCID: PMC6883518 DOI: 10.1186/s13023-019-1225-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 10/09/2019] [Indexed: 11/10/2022] Open
Abstract
Objective The objective was to deepen the understanding of the causes of individual variability in phenylketonuria (PKU) by investigating which metabolic variables are most important for predicting cognitive outcomes (Phe average vs Phe variation) and by assessing the risk of cognitive impairment associated with adopting a more relaxed approach to the diet than is currently recommended. Method We analysed associations between metabolic and cognitive measures in a mixed sample of English and Italian early-treated adults with PKU (N = 56). Metabolic measures were collected through childhood, adolescence and adulthood; cognitive measures were collected in adulthood. Metabolic measures included average Phe levels (average of median values for each year in a given period) and average Phe variations (average yearly standard deviations). Cognition was measured with IQ and a battery of cognitive tasks. Results Phe variation was as important, if not more important, than Phe average in predicting adult outcomes and contributed independently. Phe variation was particularly detrimental in childhood. Together, childhood Phe variation and adult Phe average predicted around 40% of the variation in cognitive scores. Poor cognitive scores (> 1 SD from controls) occurred almost exclusively in individuals with poor metabolic control and the risk of poor scores was about 30% higher in individuals with Phe values exceeding recommended thresholds. Conclusions Our results provide support for current European guidelines (average Phe value = < 360 μmol/l in childhood; = < 600 μmo/l from 12 years onwards), but they suggest an additional recommendation to maintain stable levels (possibly Phe SD = < 180 μmol/l throughout life). Public significance statements We investigated the relationship between how well people with phenylketonuria control blood Phe throughout their life and their ability to carry out cognitive tasks in adulthood. We found that avoiding blood Phe peaks was as important if not more important that maintaining average low Phe levels. This was particularly essential in childhood. We also found that blood Phe levels above recommended European guidelines was associated with around 30% increase in the risk of poor cognitive outcomes.
Collapse
Affiliation(s)
- Cristina Romani
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, England, B4 7ET, UK.
| | - Filippo Manti
- Department of Human Neuroscience - Unit of Child Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy
| | - Francesca Nardecchia
- Department of Human Neuroscience - Unit of Child Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy
| | | | | | - Claudia Carducci
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | - Sabrina De Leo
- Department of Clinical Medicine, Policlinico Umberto I, Rome, Italy
| | - Anita MacDonald
- Birmingham Women's and Children's NHS Foundation Trust, Birmingham, UK
| | - Liana Palermo
- Department of Medical and Surgical Sciences, Magna Graecia University of Catanzaro, Catanzaro, Italy
| | - Vincenzo Leuzzi
- Department of Human Neuroscience - Unit of Child Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy
| |
Collapse
|
16
|
Douglas TD, Nucci AM, Berry AM, Henes ST, Singh RH. Large neutral amino acid status in association with P:T ratio and diet in adult and pediatric patients with phenylketonuria. JIMD Rep 2019; 50:50-59. [PMID: 31741827 PMCID: PMC6850973 DOI: 10.1002/jmd2.12076] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 08/09/2019] [Accepted: 08/13/2019] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Intake of large neutral amino acids (LNAA) may inhibit phenylalanine (PHE) transport across the blood brain barrier and assist with blood PHE control in patients with phenylketonuria (PKU). We evaluated the interrelationship between LNAA in plasma and diet on Phe:Tyr (P:T) ratio in patients with PKU and the influence of dietary factors on plasma LNAA markers. METHODS Plasma amino acid values and 3-day food record analysis from two studies (34 male/30 female; age 4.6-47 years) were examined. For pediatrics (<18 years) and adults (≥18 years) the relationship between P:T ratio, plasma LNAA, and dietary intake patterns were investigated. RESULTS Dietary factors influencing P:T ratio included intake of total protein (g/kg), medical food (MF) protein (g/kg, % below Rx), and LNAA (g) in the full cohort (P < .05). Associations were found between plasma valine and other dietary and plasma LNAA in pediatrics (P < .05) and plasma LNAA with dietary LNAA intake in adults (P = .019). Plasma P:T ratio was inversely associated with plasma LNAA concentrations in both age groups (P < .05). Aside from histidine in pediatrics (P = .024), plasma LNAA did not differ by having plasma PHE levels within or above the therapeutic range (120-360 μmol/L). Plasma LNAA in both age groups was similar to reported healthy control values. CONCLUSION P:T ratio is significantly tied to dietary LNAA, adherence to MF Rx, and plasma LNAA concentrations. Additionally, P:T ratio and valine may be effective clinical proxies for determining LNAA metabolic balance and LNAA quality of the diet in patients with PKU.
Collapse
Affiliation(s)
| | - Anita M. Nucci
- Department of NutritionGeorgia State UniversityAtlantaGeorgia
| | - Ann M. Berry
- Department of NutritionGeorgia State UniversityAtlantaGeorgia
| | - Sarah T. Henes
- Department of NutritionGeorgia State UniversityAtlantaGeorgia
| | - Rani H. Singh
- Department of Human GeneticsEmory UniversityAtlantaGeorgia
| |
Collapse
|
17
|
Large Neutral Amino Acid Therapy Increases Tyrosine Levels in Adult Patients with Phenylketonuria: A Long-Term Study. Nutrients 2019; 11:nu11102541. [PMID: 31640267 PMCID: PMC6835503 DOI: 10.3390/nu11102541] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 10/14/2019] [Accepted: 10/16/2019] [Indexed: 12/23/2022] Open
Abstract
The standard treatment for phenylketonuria (PKU) is a lifelong low-phenylalanine (Phe) diet, supplemented with Phe-free protein substitutes; however, adult patients often show poor adherence to therapy. Alternative treatment options include the use of large neutral amino acids (LNAA). The aim of this study was to determine the Phe, tyrosine (Tyr), and Phe/Tyr ratio in a cohort of sub-optimally controlled adult patients with classical PKU treated with a new LNAA formulation. Twelve patients received a Phe-restricted diet plus a slow-release LNAA product taken three times per day, at a dose of 1 g/kg body weight (mean 0.8 ± 0.24 g/kg/day), over a 12-month period. The product is in a microgranulated formulation, which incorporates all amino acids and uses sodium alginate as a hydrophilic carrier to prolong its release. This LNAA formulation provides up to 80% of the total protein requirement, with the rest of the protein supplied by natural food. Patients had fortnightly measurements of Phe and Tyr levels over a 12-month period after the introduction of LNAA. All patients completed the 12-month treatment period. Overall, adherence to the new LNAA tablets was very good compared with a previous amino acid mixture, for which taste was a major complaint by patients. Phe levels remained unchanged (p = 0.0522), and Tyr levels increased (p = 0.0195). Consequently, the Phe/Tyr ratio decreased significantly (p < 0.05) in the majority of patients treated. In conclusion, LNAA treatment increases Tyr levels in sub-optimally controlled adult PKU patients, while offering the potential to improve their adherence to treatment.
Collapse
|
18
|
Green B, Browne R, Firman S, Hill M, Rahman Y, Kaalund Hansen K, Adam S, Skeath R, Hallam P, Herlihy I, Jenkinson F, Nicol C, Adams S, Gaff L, Donald S, Dawson C, Robertson L, Fitzachary C, Chan H, Slabbert A, Dunlop C, Cozens A, Newby C, Bittle V, Hubbard G, Stratton R. Nutritional and Metabolic Characteristics of UK Adult Phenylketonuria Patients with Varying Dietary Adherence. Nutrients 2019; 11:nu11102459. [PMID: 31615158 PMCID: PMC6835765 DOI: 10.3390/nu11102459] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 09/30/2019] [Accepted: 10/11/2019] [Indexed: 01/20/2023] Open
Abstract
The nutritional and metabolic characteristics of adult phenylketonuria (PKU) patients in the UK with varying dietary adherence is unknown. In other countries, nutritional and metabolic abnormalities have been reported in nonadherent patients compared to adherent counterparts. A pooled analysis of primary baseline data from two UK multi-centre studies was therefore performed to establish whether this is true from a UK perspective. Adult PKU patients who had provided 3-day food records and amino acid blood samples were included and grouped according to dietary adherence (adherent; n = 16 vs. nonadherent; n = 14). Nonadherent patients consumed greater amounts of natural protein compared to adherent patients (61.6 ± 30.7 vs. 18.3 ± 7.7 g/day; q < 0.001). In contrast, the contribution of protein substitutes to total protein intake was lower in nonadherent compared to adherent patients (3.9 ± 9.2 g/day vs. 58.6 ± 10.2 g/day; q < 0.001). Intakes of iron, zinc, vitamin D3, magnesium, calcium, selenium, iodine, vitamin C, vitamin A and copper were significantly lower in nonadherent compared to adherent patients and were below UK Reference Nutrient Intakes. Similarly, intakes of thiamin, riboflavin, niacin, vitamin B6 and phosphorus were significantly lower in nonadherent compared to adherent patients but met the UK Reference Nutrient Intakes. Phenylalanine concentrations in nonadherent patients were significantly higher than adherent patients (861 ± 348 vs. 464 ± 196 µmol/L; q=0.040) and fell outside of European treatment target ranges. This study shows the nutritional and metabolic consequences of deviation from phenylalanine restriction and intake of PKU protein substitutes in nonadherent adult PKU patients. Collectively, these data further underlie the importance of life-long adherence to the PKU diet.
Collapse
Affiliation(s)
- Benjamin Green
- Medical Affairs, Nutricia Advanced Medical Nutrition, Wiltshire BA14 0XQ, UK.
| | - Robert Browne
- Medical Affairs, Nutricia Advanced Medical Nutrition, Wiltshire BA14 0XQ, UK.
| | - Sarah Firman
- Guy's and St Thomas' NHS Foundation Trust, London SE1 9RT, UK.
| | - Melanie Hill
- Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield S10 2JF, UK.
| | - Yusof Rahman
- Guy's and St Thomas' NHS Foundation Trust, London SE1 9RT, UK.
| | - Kit Kaalund Hansen
- University College London Hospitals NHS Foundation Trust, London WC1N 3BG, UK.
| | - Sarah Adam
- Royal Hospital for Children, Glasgow, Glasgow G51 4TF, UK.
| | - Rachel Skeath
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK.
| | - Paula Hallam
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK.
| | - Ide Herlihy
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK.
| | - Fiona Jenkinson
- Royal Victoria Infirmary, Newcastle, Newcastle upon Tyne NE1 4LP, UK.
| | - Claire Nicol
- Royal Victoria Infirmary, Newcastle, Newcastle upon Tyne NE1 4LP, UK.
| | - Sandra Adams
- Royal Victoria Infirmary, Newcastle, Newcastle upon Tyne NE1 4LP, UK.
| | - Lisa Gaff
- Cambridge University Hospitals NHS Foundation Trust, Cambridge CB2 0QQ, UK.
| | - Sarah Donald
- Cambridge University Hospitals NHS Foundation Trust, Cambridge CB2 0QQ, UK.
| | | | | | | | - Heidi Chan
- Medical Affairs, Nutricia Advanced Medical Nutrition, Wiltshire BA14 0XQ, UK.
- Guy's and St Thomas' NHS Foundation Trust, London SE1 9RT, UK.
| | - Arlene Slabbert
- Guy's and St Thomas' NHS Foundation Trust, London SE1 9RT, UK.
| | - Carolyn Dunlop
- Royal Hospital for Sick Children, Edinburgh EH9 1LF, UK.
| | - Alison Cozens
- Royal Hospital for Sick Children, Edinburgh EH9 1LF, UK.
| | - Camille Newby
- Bristol University Hospitals NHS Foundation Trust, Bristol BS1 3NU, UK.
| | - Victoria Bittle
- Bristol University Hospitals NHS Foundation Trust, Bristol BS1 3NU, UK.
| | - Gary Hubbard
- Medical Affairs, Nutricia Advanced Medical Nutrition, Wiltshire BA14 0XQ, UK.
| | - Rebecca Stratton
- Medical Affairs, Nutricia Advanced Medical Nutrition, Wiltshire BA14 0XQ, UK.
- Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK.
| |
Collapse
|
19
|
van Vliet D, van der Goot E, van Ginkel WG, van Faassen MHJR, de Blaauw P, Kema IP, Martinez A, Heiner-Fokkema MR, van der Zee EA, van Spronsen FJ. The Benefit of Large Neutral Amino Acid Supplementation to a Liberalized Phenylalanine-Restricted Diet in Adult Phenylketonuria Patients: Evidence from Adult Pah-Enu2 Mice. Nutrients 2019; 11:E2252. [PMID: 31546852 PMCID: PMC6770592 DOI: 10.3390/nu11092252] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 09/13/2019] [Accepted: 09/17/2019] [Indexed: 11/16/2022] Open
Abstract
Many phenylketonuria (PKU) patients cannot adhere to the severe dietary restrictions as advised by the European PKU guidelines, which can be accompanied by aggravated neuropsychological impairments that, at least in part, have been attributed to brain monoaminergic neurotransmitter deficiencies. Supplementation of large neutral amino acids (LNAA) to an unrestricted diet has previously been shown to effectively improve brain monoamines in PKU mice of various ages. To determine the additive value of LNAA supplementation to a liberalized phenylalanine-restricted diet, brain and plasma monoamine and amino acid concentrations in 10 to 16-month-old adult C57Bl/6 PKU mice on a less severe phenylalanine-restricted diet with LNAA supplementation were compared to those on a non-supplemented severe or less severe phenylalanine-restricted diet. LNAA supplementation to a less severe phenylalanine-restricted diet was found to improve both brain monoamine and phenylalanine concentrations. Compared to a severe phenylalanine-restricted diet, it was equally effective to restore brain norepinephrine and serotonin even though being less effective to reduce brain phenylalanine concentrations. These results in adult PKU mice support the idea that LNAA supplementation may enhance the effect of a less severe phenylalanine-restricted diet and suggest that cerebral outcome of PKU patients treated with a less severe phenylalanine-restricted diet may be helped by additional LNAA treatment.
Collapse
Affiliation(s)
- Danique van Vliet
- Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, 9700 RB Groningen, The Netherlands.
| | - Els van der Goot
- Department of Molecular Neurobiology, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, 9700 RB Groningen, The Netherlands.
| | - Wiggert G van Ginkel
- Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, 9700 RB Groningen, The Netherlands.
| | - Martijn H J R van Faassen
- Department of Laboratory Medicine, University Medical Center Groningen, University of Groningen, 9700 RB Groningen, The Netherlands.
| | - Pim de Blaauw
- Department of Laboratory Medicine, University Medical Center Groningen, University of Groningen, 9700 RB Groningen, The Netherlands.
| | - Ido P Kema
- Department of Laboratory Medicine, University Medical Center Groningen, University of Groningen, 9700 RB Groningen, The Netherlands.
| | - Aurora Martinez
- Department of Biomedicine and K.G. Jebsen Centre for Neuropsychiatric Disorders, University of Bergen, 5009 Bergen, Norway.
| | - M Rebecca Heiner-Fokkema
- Department of Laboratory Medicine, University Medical Center Groningen, University of Groningen, 9700 RB Groningen, The Netherlands.
| | - Eddy A van der Zee
- Department of Molecular Neurobiology, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, 9700 RB Groningen, The Netherlands.
| | - Francjan J van Spronsen
- Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, 9700 RB Groningen, The Netherlands.
| |
Collapse
|
20
|
Neuropsychological Profile of Children with Early and Continuously Treated Phenylketonuria: Systematic Review and Future Approaches. J Int Neuropsychol Soc 2019; 25:624-643. [PMID: 31030702 DOI: 10.1017/s1355617719000146] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE To provide a comprehensive systematic review of the literature by examining studies published on all cognitive aspects of children with early and continuously treated phenylketonuria (ECT-PKU) included in the databases Medline, PsycINFO, and PsycARTICLE. METHOD In addition to a classical approach, we summarized methodology and results of each study in order to discuss current theoretical and methodological issues. We also examined recent advances in biochemical markers and treatments of PKU, with implications for future research on metabolic control and its role as a determinant of neuropsychological outcome. RESULTS Consistent with previous reviews, the hypothesis of a specific and central executive impairment in children with ECT-PKU was suggested. However, findings are inconclusive regarding the nature of executive impairments as well as their specificity, impact on everyday life, persistence over time, and etiology. CONCLUSION Given the current state of the science, we suggest future directions for research that utilizes a developmental and integrative approach to examine the effects of recent advances in biochemical markers and treatment of PKU. (JINS, 2019, 25, 624-643).
Collapse
|
21
|
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
| |
Collapse
|
22
|
Taslimifar M, Buoso S, Verrey F, Kurtcuoglu V. Propagation of Plasma L-Phenylalanine Concentration Fluctuations to the Neurovascular Unit in Phenylketonuria: An in silico Study. Front Physiol 2019; 10:360. [PMID: 31105574 PMCID: PMC6454150 DOI: 10.3389/fphys.2019.00360] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 03/14/2019] [Indexed: 01/21/2023] Open
Abstract
Phenylketonuria (PKU) is an inherited metabolic disease characterized by abnormally high concentrations of the essential amino acid L-phenylalanine (Phe) in blood plasma caused by reduced activity of phenylalanine hydroxylase (PAH). While numerous studies have shown association between high plasma Phe concentration and intellectual impairment, it is not clear whether increased Phe fluctuations also observed in PKU affect the brain as well. To investigate this, time-resolved in vivo data on Phe and competing large neutral amino acid (LNAA) concentrations in neurons are needed, but cannot be acquired readily with current methods. We have used in silico modeling as an alternative approach to characterize the interactive dynamics of Phe and competing LNAAs (CL) in the neurovascular unit (NVU). Our results suggest that plasma Phe fluctuations can propagate into the NVU cells and change there the concentration of LNAAs, with the highest magnitude of this effect observed at low frequency and high amplitude-to-mean ratio of the plasma Phe concentration fluctuations. Our model further elucidates the effect of therapeutic LNAA supplementation in PKU, showing how abnormal concentrations of Phe and CL in the NVU move thereby toward normal physiologic levels.
Collapse
Affiliation(s)
- Mehdi Taslimifar
- The Interface Group, Institute of Physiology, University of Zurich, Zurich, Switzerland.,Epithelial Transport Group, Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Stefano Buoso
- The Interface Group, Institute of Physiology, University of Zurich, Zurich, Switzerland.,Institute for Diagnostic and Interventional Radiology, Zurich University Hospital, Zurich, Switzerland
| | - Francois Verrey
- Epithelial Transport Group, Institute of Physiology, University of Zurich, Zurich, Switzerland.,Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland.,National Center of Competence in Research, Kidney Control of Homeostasis, Zurich, Switzerland
| | - Vartan Kurtcuoglu
- The Interface Group, Institute of Physiology, University of Zurich, Zurich, Switzerland.,Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland.,National Center of Competence in Research, Kidney Control of Homeostasis, Zurich, Switzerland.,Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
| |
Collapse
|
23
|
Kumru B, Ozturk Hismi B, Kaplan DS, Celik H. Studying the effect of large neutral amino acid supplements on oxidative stress in phenylketonuric patients. J Pediatr Endocrinol Metab 2019; 32:269-274. [PMID: 30835252 DOI: 10.1515/jpem-2018-0454] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 01/16/2019] [Indexed: 11/15/2022]
Abstract
Background Oxidative stress may be one of the causes responsible for mental retardation in phenylketonuria (PKU) patients. Phenylalanine (Phe) reduces antioxidant defense and promotes oxidative stress by causing increase in reactive oxygen-nitrogen species. Our study aimed to investigate the effect of different treatments (amino acid mixture/large neutral amino acid [LNAA] supplements) on oxidative stress which are applied to late-diagnosed patients. To the best of our knowledge, this is the first study to investigate the effect of LNAA supplements on oxidative stress. Methods Twenty late-diagnosed classic PKU patients were included in this study. Patients were classified into two groups: patients under Phe-restricted diet and using Phe-free amino acid mixtures (Group I) (mean age: 13.8 ± 2.8), and patients taking LNAA supplements (Group II) (mean age: 14.8 ± 3.8). Healthy controls (mean age: 13.6 ± 4.8) with ages consistent with the ages of the patients in the experimental groups were included. Results Glutathione peroxidase is lower in patients of taking LNAA supplements than the control group (p = 0.022). Coenzyme Q10 is lower in patients of using Phe-free amino acid mixtures than the control group and it is significantly higher in Group II than Group I (p = 0.0001, p = 0.028, respectively). No significant differences were detected in total antioxidant status, total oxidant status, oxidative stress index, paraoxonase 1 and L-carnitine levels. Conclusions Different treatments affect oxidative stress parameters in PKU patients. In this study, although patients were followed up with classic PKU, patient-specific adjuvant antioxidant therapies should be implemented in response to oxidative stress.
Collapse
Affiliation(s)
- Burcu Kumru
- Division of Nutrition and Diet, Gaziantep Cengiz Gökçek Maternity and Children's Hospital, Gaziantep, Turkey, Phone: +905321623092, Fax: +03423600888
| | - Burcu Ozturk Hismi
- Division of Pediatric Metabolism and Nutrition, Tepecik Training and Research Hospital, Izmir, Turkey
| | | | - Hakim Celik
- Division of Physiology, Harran University, Sanlıurfa, Turkey
| |
Collapse
|
24
|
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.
Collapse
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
| |
Collapse
|
25
|
Rocha JC, MacDonald A. Treatment options and dietary supplements for patients with phenylketonuria. Expert Opin Orphan Drugs 2018. [DOI: 10.1080/21678707.2018.1536541] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Júlio César Rocha
- Centro de Genética Médica, Centro Hospitalar do Porto - CHP, Porto, Portugal
- Faculdade de Ciências da Saúde, Universidade Fernando Pessoa, Porto, Portugal
- Center for Health Technology and Services Research (CINTESIS), Porto, Portugal
| | | |
Collapse
|
26
|
Ahring KK, Lund AM, Jensen E, Jensen TG, Brøndum-Nielsen K, Pedersen M, Bardow A, Holst JJ, Rehfeld JF, Møller LB. Comparison of Glycomacropeptide with Phenylalanine Free-Synthetic Amino Acids in Test Meals to PKU Patients: No Significant Differences in Biomarkers, Including Plasma Phe Levels. J Nutr Metab 2018; 2018:6352919. [PMID: 29511574 PMCID: PMC5817308 DOI: 10.1155/2018/6352919] [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: 07/14/2017] [Accepted: 10/11/2017] [Indexed: 11/17/2022] Open
Abstract
INTRODUCTION Management of phenylketonuria (PKU) is achieved through low-phenylalanine (Phe) diet, supplemented with low-protein food and mixture of free-synthetic (FS) amino acid (AA). Casein glycomacropeptide (CGMP) is a natural peptide released in whey during cheese-making and does not contain Phe. Lacprodan® CGMP-20 used in this study contained a small amount of Phe due to minor presence of other proteins/peptides. OBJECTIVE The purpose of this study was to compare absorption of CGMP-20 to FSAA with the aim of evaluating short-term effects on plasma AAs as well as biomarkers related to food intake. METHODS This study included 8 patients, who had four visits and tested four drink mixtures (DM1-4), consisting of CGMP, FSAA, or a combination. Plasma blood samples were collected at baseline, 15, 30, 60, 120, and 240 minutes (min) after the meal. AA profiles and ghrelin were determined 6 times, while surrogate biomarkers were determined at baseline and 240 min. A visual analogue scale (VAS) was used for evaluation of taste and satiety. RESULTS The surrogate biomarker concentrations and VAS scores for satiety and taste were nonsignificant between the four DMs, and there were only few significant results for AA profiles (not Phe). CONCLUSION CGMP and FSAA had the overall same nonsignificant short-term effect on biomarkers, including Phe. This combination of FSAA and CGMP is a suitable supplement for PKU patients.
Collapse
Affiliation(s)
- Kirsten K. Ahring
- The PKU Clinic, Kennedy Centre, Centre for Paediatric and Adolescent Medicine, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
- Department of Clinical Genetics, Applied Human Molecular Genetics, Kennedy Center, Rigshospitalet, Denmark
- Centre for Inherited Metabolic Diseases, Centre for Paediatric and Adolescent Medicine, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Allan M. Lund
- Department of Clinical Genetics, Applied Human Molecular Genetics, Kennedy Center, Rigshospitalet, Denmark
- Centre for Inherited Metabolic Diseases, Centre for Paediatric and Adolescent Medicine, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Erik Jensen
- Arla Foods Ingredients Group P/S, Viby J, Denmark
| | | | - Karen Brøndum-Nielsen
- The PKU Clinic, Kennedy Centre, Centre for Paediatric and Adolescent Medicine, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Michael Pedersen
- Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Allan Bardow
- Department of Odontology, Copenhagen University, Copenhagen, Denmark
| | - Jens Juul Holst
- Institute of Clinical Medicine, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Jens F. Rehfeld
- Department of Clinical Biochemistry, University of Copenhagen, Rigshospitalet, Copenhagen, Denmark
| | - Lisbeth B. Møller
- Department of Clinical Genetics, Applied Human Molecular Genetics, Kennedy Center, Rigshospitalet, Denmark
| |
Collapse
|
27
|
Winn SR, Scherer T, Thöny B, Ying M, Martinez A, Weber S, Raber J, Harding CO. Blood phenylalanine reduction corrects CNS dopamine and serotonin deficiencies and partially improves behavioral performance in adult phenylketonuric mice. Mol Genet Metab 2018; 123:6-20. [PMID: 29331172 PMCID: PMC5786171 DOI: 10.1016/j.ymgme.2017.10.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 10/17/2017] [Accepted: 10/17/2017] [Indexed: 01/12/2023]
Abstract
Central nervous system (CNS) deficiencies of the monoamine neurotransmitters dopamine and serotonin have been implicated in the pathophysiology of neuropsychiatric dysfunction in human phenylketonuria (PKU). In this study, we confirmed the occurrence of brain dopamine and serotonin deficiencies in association with severe behavioral alterations and cognitive impairments in hyperphenylalaninemic C57BL/6-Pahenu2/enu2 mice, a model of human PKU. Phenylalanine-reducing treatments, including either dietary phenylalanine restriction or liver-directed gene therapy, initiated during adulthood were associated with increased brain monoamine content along with improvements in nesting behavior but without a change in the severe cognitive deficits exhibited by these mice. At euthanasia, there was in Pahenu2/enu2 brain a significant reduction in the protein abundance and maximally stimulated activities of tyrosine hydroxylase (TH) and tryptophan hydroxylase 2 (TPH2), the rate limiting enzymes catalyzing neuronal dopamine and serotonin synthesis respectively, in comparison to levels seen in wild type brain. Phenylalanine-reducing treatments initiated during adulthood did not affect brain TH or TPH2 content or maximal activity. Despite this apparent fixed deficit in striatal TH and TPH2 activities, initiation of phenylalanine-reducing treatments yielded substantial correction of brain monoamine neurotransmitter content, suggesting that phenylalanine-mediated competitive inhibition of already constitutively reduced TH and TPH2 activities is the primary cause of brain monoamine deficiency in Pahenu2 mouse brain. We propose that CNS monoamine deficiency may be the cause of the partially reversible adverse behavioral effects associated with chronic HPA in Pahenu2 mice, but that phenylalanine-reducing treatments initiated during adulthood are unable to correct the neuropathology and attendant cognitive deficits that develop during juvenile life in late-treated Pahenu2/enu2 mice.
Collapse
Affiliation(s)
- Shelley R Winn
- Department of Medical and Molecular Genetics, Oregon Health & Science University, Mailstop L-103, 3181 Sam Jackson Park Rd., Portland, OR 97239, USA
| | - Tanja Scherer
- Department of Pediatrics, University of Zurich, Steinweissstrasse 75, Zurich CH-8032, Switzerland
| | - Beat Thöny
- Department of Pediatrics, University of Zurich, Steinweissstrasse 75, Zurich CH-8032, Switzerland
| | - Ming Ying
- Department of Biomedicine, KG Jebsen Centre for Neuropsychiatric Disorders, University of Bergen, 5009 Bergen, Norway
| | - Aurora Martinez
- Department of Biomedicine, KG Jebsen Centre for Neuropsychiatric Disorders, University of Bergen, 5009 Bergen, Norway
| | - Sydney Weber
- Department of Behavioral Neuroscience, Oregon Health & Science University, 3181 Sam Jackson Park Rd., Portland, OR 97239, USA
| | - Jacob Raber
- Department of Behavioral Neuroscience, Oregon Health & Science University, 3181 Sam Jackson Park Rd., Portland, OR 97239, USA; Department of Neurology, Division of Neuroscience, ONPRC, Oregon Health & Science University, 3181 Sam Jackson Park Rd., Portland, OR 97239, USA; Department of Radiation Medicine, Division of Neuroscience, ONPRC, Oregon Health & Science University, 3181 Sam Jackson Park Rd., Portland, OR 97239, USA
| | - Cary O Harding
- Department of Medical and Molecular Genetics, Oregon Health & Science University, Mailstop L-103, 3181 Sam Jackson Park Rd., Portland, OR 97239, USA.
| |
Collapse
|
28
|
Potter BK, Hutton B, Clifford TJ, Pallone N, Smith M, Stockler S, Chakraborty P, Barbeau P, Garritty CM, Pugliese M, Rahman A, Skidmore B, Tessier L, Tingley K, Coyle D, Greenberg CR, Korngut L, MacKenzie A, Mitchell JJ, Nicholls S, Offringa M, Schulze A, Taljaard M. Establishing core outcome sets for phenylketonuria (PKU) and medium-chain Acyl-CoA dehydrogenase (MCAD) deficiency in children: study protocol for systematic reviews and Delphi surveys. Trials 2017; 18:603. [PMID: 29258568 PMCID: PMC5735866 DOI: 10.1186/s13063-017-2327-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 11/13/2017] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Inherited metabolic diseases (IMD) are a large group of rare single-gene disorders that are typically diagnosed early in life. There are important evidence gaps related to the comparative effectiveness of therapies for IMD, which are in part due to challenges in conducting randomized controlled trials (RCTs) for rare diseases. Registry-based RCTs present a unique opportunity to address these challenges provided the registries implement standardized collection of outcomes that are important to patients and their caregivers and to clinical providers and healthcare systems. Currently there is no core outcome set (COS) for studies evaluating interventions for paediatric IMD. This protocol outlines a study that will establish COS for each of two relatively common IMD in children, phenylketonuria (PKU) and medium-chain acyl-CoA dehydrogenase (MCAD) deficiency. METHODS This two-part study is registered with the Core Outcome Measures in Effectiveness Trials (COMET) initiative. Part 1 includes a rapid review and development of an evidence map to identify a comprehensive listing of outcomes reported in past studies of PKU and MCAD deficiency. The review follows established methods for knowledge synthesis, including a comprehensive search strategy, two stages of screening citations against inclusion/exclusion criteria by two reviewers working independently, and extraction of important data elements from eligible studies, including details of the outcomes collected and outcome measurement instruments. The review findings will inform part 2 of our study, a set of Delphi surveys to establish consensus on the highest priority outcomes for each condition. Healthcare providers, families of children with PKU or MCAD deficiency, and health system decision-makers will be invited to participate in two to three rounds of Delphi surveys. The design of the surveys will involve parents of children with IMD who are part of a family advisory forum. DISCUSSION This protocol is a crucial step in developing the capacity to launch RCTs with meaningful outcomes that address comparative effectiveness questions in the field of paediatric IMD. Such trials will contribute high-quality evidence to inform decision-making by patients and their family members, clinicians, and policy-makers.
Collapse
Affiliation(s)
- Beth K. Potter
- School of Epidemiology and Public Health, University of Ottawa, 600 Peter Morand Drive, Ottawa, ON K1G 5Z3 Canada
| | - Brian Hutton
- School of Epidemiology and Public Health, University of Ottawa, 600 Peter Morand Drive, Ottawa, ON K1G 5Z3 Canada
- Ottawa Hospital Research Institute, Ottawa, ON Canada
| | - Tammy J. Clifford
- School of Epidemiology and Public Health, University of Ottawa, 600 Peter Morand Drive, Ottawa, ON K1G 5Z3 Canada
- Canadian Agency for Drugs and Technologies in Health, Ottawa, ON Canada
| | - Nicole Pallone
- Patient/family partner and Canadian PKU & Allied Disorders Inc, Sparwood, BC Canada
| | - Maureen Smith
- Patient/family partner and Canadian Organization for Rare Disorders, Ottawa, ON Canada
| | - Sylvia Stockler
- BC Children’s Hospital and University of British Columbia, Vancouver, BC Canada
| | - Pranesh Chakraborty
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, ON Canada
| | | | | | - Michael Pugliese
- School of Epidemiology and Public Health, University of Ottawa, 600 Peter Morand Drive, Ottawa, ON K1G 5Z3 Canada
| | - Alvi Rahman
- School of Epidemiology and Public Health, University of Ottawa, 600 Peter Morand Drive, Ottawa, ON K1G 5Z3 Canada
| | | | - Laure Tessier
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, ON Canada
| | - Kylie Tingley
- School of Epidemiology and Public Health, University of Ottawa, 600 Peter Morand Drive, Ottawa, ON K1G 5Z3 Canada
| | - Doug Coyle
- School of Epidemiology and Public Health, University of Ottawa, 600 Peter Morand Drive, Ottawa, ON K1G 5Z3 Canada
| | | | - Lawrence Korngut
- Department of Clinical Neurosciences, University of Calgary, Calgary, AB Canada
| | - Alex MacKenzie
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, ON Canada
| | | | - Stuart Nicholls
- Clinical Research Unit, Children’s Hospital of Eastern Ontario, Ottawa, ON Canada
- Ontario Child Health SUPPORT Unit (OCHSU), Ottawa, ON Canada
| | - Martin Offringa
- Hospital for Sick Children and University of Toronto, Toronto, ON Canada
| | - Andreas Schulze
- Hospital for Sick Children and University of Toronto, Toronto, ON Canada
| | - Monica Taljaard
- School of Epidemiology and Public Health, University of Ottawa, 600 Peter Morand Drive, Ottawa, ON K1G 5Z3 Canada
- Ottawa Hospital Research Institute, Ottawa, ON Canada
| | - In collaboration with the Canadian Inherited Metabolic Diseases Research Network
- School of Epidemiology and Public Health, University of Ottawa, 600 Peter Morand Drive, Ottawa, ON K1G 5Z3 Canada
- Ottawa Hospital Research Institute, Ottawa, ON Canada
- Canadian Agency for Drugs and Technologies in Health, Ottawa, ON Canada
- Patient/family partner and Canadian PKU & Allied Disorders Inc, Sparwood, BC Canada
- Patient/family partner and Canadian Organization for Rare Disorders, Ottawa, ON Canada
- BC Children’s Hospital and University of British Columbia, Vancouver, BC Canada
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, ON Canada
- University of Manitoba, Winnipeg, MB Canada
- Department of Clinical Neurosciences, University of Calgary, Calgary, AB Canada
- McGill University Health Centre, Montreal, QC Canada
- Clinical Research Unit, Children’s Hospital of Eastern Ontario, Ottawa, ON Canada
- Ontario Child Health SUPPORT Unit (OCHSU), Ottawa, ON Canada
- Hospital for Sick Children and University of Toronto, Toronto, ON Canada
| |
Collapse
|
29
|
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.
Collapse
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
| |
Collapse
|
30
|
Stroup BM, Murali SG, Nair N, Sawin EA, Rohr F, Levy HL, Ney DM. Dietary amino acid intakes associated with a low-phenylalanine diet combined with amino acid medical foods and glycomacropeptide medical foods and neuropsychological outcomes in subjects with phenylketonuria. Data Brief 2017; 13:377-384. [PMID: 28664173 PMCID: PMC5480823 DOI: 10.1016/j.dib.2017.06.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 05/10/2017] [Accepted: 06/01/2017] [Indexed: 11/27/2022] Open
Abstract
This article provides original data on median dietary intake of 18 amino acids from amino acid medical foods, glycomacropeptide medical foods, and natural foods based on 3-day food records obtained from subjects with phenylketonuria who consumed low-phenylalanine diets in combination with amino acid medical foods and glycomacropeptide medical foods for 3 weeks each in a crossover design. The sample size of 30 subjects included 20 subjects with classical phenylketonuria and 10 with a milder or variant form of phenylketonuria. Results are presented for the Delis-Kaplan Executive Function System and the Cambridge Neuropsychological Test Automated Battery; the tests were administered at the end of each 3-week dietary treatment with amino acid medical foods and glycomacropeptide medical foods. The data are supplemental to our clinical trial, entitled “Glycomacropetide for nutritional management of phenylketonuria: a randomized, controlled, crossover trial, 2016 (1) and “Metabolomic changes demonstrate reduced bioavailability of tyrosine and altered metabolism of tryptophan via the kynurenine pathway with ingestion of medical foods in phenylketonuria, 2017 (2). This data has been made public and has utility to clinicians and researchers due to the following: 1) This provides the first comprehensive report of typical intakes of 18 amino acids from natural foods, as well as amino acid and glycomacropeptide medical foods in adolescents and adults with phenylketonuria; and 2) This is the first evidence of similar standardized neuropsychological testing data in adolescents and adults with early-treated phenylketonuria who consumed amino acid and glycomacropeptide medical foods.
Collapse
Affiliation(s)
- Bridget M Stroup
- Department of Nutritional Sciences, University of Wisconsin-Madison, WI, United States
| | - Sangita G Murali
- Department of Nutritional Sciences, University of Wisconsin-Madison, WI, United States
| | - Nivedita Nair
- Department of Nutritional Sciences, University of Wisconsin-Madison, WI, United States
| | - Emily A Sawin
- Department of Nutritional Sciences, University of Wisconsin-Madison, WI, United States
| | - Fran Rohr
- Division of Genetics and Genomics, Boston Children׳s Hospital, Harvard Medical School, Boston, MA, United States
| | - Harvey L Levy
- Division of Genetics and Genomics, Boston Children׳s Hospital, Harvard Medical School, Boston, MA, United States
| | - Denise M Ney
- Department of Nutritional Sciences, University of Wisconsin-Madison, WI, United States
| |
Collapse
|
31
|
Rahim F, Saki Malehi A, Mohammadshahi M, Tirdad R. Combined large neutral amino acid supplementation for phenylketonuria (PKU). Hippokratia 2017. [DOI: 10.1002/14651858.cd012618] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Fakher Rahim
- Health Research Institute, Ahvaz Jundishapur University of Medical Sciences; Thalassemia & Hemoglobinopathy Research Center; Golestan Avenue Ahvaz Khuzestan Iran 61537-15794
| | - Amal Saki Malehi
- Ahvaz Jundishapur University of Medical Sciences; Department of Biostatistics and Epidemiology, School of Public Health; Golestan Ahvaz Khuzestan Iran 61537-15794
| | - Majid Mohammadshahi
- Ahvaz Jundishapur University of Medical Sciences; Department of Molecular Medicine and Molecular Epidemiology; Golestan Ahvaz Khuzestan Iran 61537-15794
| | - Roshanak Tirdad
- Ahvaz Jundishapur University of Medical Sciences; Department of Molecular Medicine and Molecular Epidemiology; Golestan Ahvaz Khuzestan Iran 61537-15794
| |
Collapse
|
32
|
Rocha JC, MacDonald A. Dietary intervention in the management of phenylketonuria: current perspectives. PEDIATRIC HEALTH MEDICINE AND THERAPEUTICS 2016; 7:155-163. [PMID: 29388626 PMCID: PMC5683291 DOI: 10.2147/phmt.s49329] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Phenylketonuria (PKU) is a well-described inborn error of amino acid metabolism that has been treated for >60 years. Enzyme deficiency causes accumulation of phenylalanine (Phe) and if left untreated will lead to profound and irreversible intellectual disability in most children. Traditionally, it has been managed with a low-Phe diet supplemented with a Phe-free protein substitute although newer treatment options mainly in combination with diet are available for some subgroups of patients with PKU, for example, sapropterin, large neutral amino acids, and glycomacropeptide. The diet consists of three parts: 1) severe restriction of dietary Phe; 2) replacement of non-Phe l-amino acids with a protein substitute commonly supplemented with essential fatty acids and other micronutrients; and 3) low-protein foods from fruits, some vegetables, sugars, fats and oil, and special low-protein foods (SLPF). The prescription of diet is challenging for health professionals. The high-carbohydrate diet supplied by a limited range of foods may program food preferences and contribute to obesity in later life. Abnormal tasting and satiety-promoting protein substitutes are administered to coincide with peak appetite times to ensure their consumption, but this practice may impede appetite for other important foods. Intermittent dosing of micronutrients when combined with l-amino acid supplements may lead to their poor bioavailability. Much work is required on the ideal nutritional profiling for special SLPF and Phe-free l-amino acid supplements. Although non-diet treatments are being studied, it is important to continue to fully understand all the consequences of diet therapy as it is likely to remain the foundation of therapy for many years.
Collapse
Affiliation(s)
- Júlio César Rocha
- Centro de Genética Médica, Centro Hospitalar do Porto - CHP.,Faculdade de Ciências da Saúde, Universidade Fernando Pessoa.,Center for Health Technology and Services Research (CINTESIS), Porto, Portugal
| | | |
Collapse
|
33
|
Abstract
Cerebral neurotransmitter (NT) deficiency has been suggested as a contributing factor in the pathophysiology of brain dysfunction in phenylketonuria (PKU), even in early-treated phenylketonuric patients. The study aimed to review dopamine and serotonin status in PKU, and the effect of the impaired neurotransmission. Several mechanisms are involved in the pathophysiology of PKU, primarily characterized by impaired dopamine and serotonin synthesis. These deficits are related to executive dysfunctions and social-emotional problems, respectively, in early treated patients. Blood phenylalanine is the main biomarker for treatment compliance follow-up, but further investigations and validation of peripheral biomarkers may be performed to monitor NT status. The development of new therapies is needed not only for decreasing blood and brain phenylalanine levels but also to improve NT syntheses.
Collapse
|
34
|
Villoria JG, Pajares S, López RM, Marin JL, Ribes A. Neonatal Screening for Inherited Metabolic Diseases in 2016. Semin Pediatr Neurol 2016; 23:257-272. [PMID: 28284388 DOI: 10.1016/j.spen.2016.11.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The scope of newborn screening (NBS) programs is continuously expanding. NBS programs are secondary prevention interventions widely recognized internationally in the "field of Public Health." These interventions are aimed at early detection of asymptomatic children affected by certain diseases, with the objective to establish a definitive diagnosis and apply the proper treatment to prevent further complications and sequelae and ensure a better quality of life. The most significant event in the history of neonatal screening was the discovery of phenylketonuria in 1934. This disease has been the paradigm of inherited metabolic diseases. The next paradigm was the introduction of tandem mass spectrometry in the NBS programs that make possible the simultaneous measurement of several metabolites and consequently, the detection of several diseases in one blood spot and in an unique analysis. We aim to review the current situation of neonatal screening in 2016 worldwide and show scientific evidence of the benefits for some diseases. We will also discuss future challenges. It should be taken into account that any consideration to expand an NBS panel should involve a rigorous process of decision-making that balances benefits against the risks of harm.
Collapse
Affiliation(s)
- Judit Garcia Villoria
- From the Seccción de Errores Congénitos del Metabolismo-IBC, Servicio de Bioquímica y Genética Molecular, Hospital ClinicHospital Clínic, CIBERER, IDIBAPS, Barcelona, Spain
| | - Sonia Pajares
- From the Seccción de Errores Congénitos del Metabolismo-IBC, Servicio de Bioquímica y Genética Molecular, Hospital ClinicHospital Clínic, CIBERER, IDIBAPS, Barcelona, Spain
| | - Rosa María López
- From the Seccción de Errores Congénitos del Metabolismo-IBC, Servicio de Bioquímica y Genética Molecular, Hospital ClinicHospital Clínic, CIBERER, IDIBAPS, Barcelona, Spain
| | - José Luis Marin
- From the Seccción de Errores Congénitos del Metabolismo-IBC, Servicio de Bioquímica y Genética Molecular, Hospital ClinicHospital Clínic, CIBERER, IDIBAPS, Barcelona, Spain
| | - Antonia Ribes
- From the Seccción de Errores Congénitos del Metabolismo-IBC, Servicio de Bioquímica y Genética Molecular, Hospital ClinicHospital Clínic, CIBERER, IDIBAPS, Barcelona, Spain.
| |
Collapse
|
35
|
van Vliet D, Bruinenberg VM, Mazzola PN, van Faassen MH, de Blaauw P, Pascucci T, Puglisi-Allegra S, Kema IP, Heiner-Fokkema MR, van der Zee EA, van Spronsen FJ. Therapeutic brain modulation with targeted large neutral amino acid supplements in the Pah-enu2 phenylketonuria mouse model. Am J Clin Nutr 2016; 104:1292-1300. [PMID: 27655443 DOI: 10.3945/ajcn.116.135996] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 08/24/2016] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Phenylketonuria treatment consists mainly of a Phe-restricted diet, which leads to suboptimal neurocognitive and psychosocial outcomes. Supplementation of large neutral amino acids (LNAAs) has been suggested as an alternative dietary treatment strategy to optimize neurocognitive outcome in phenylketonuria and has been shown to influence 3 brain pathobiochemical mechanisms in phenylketonuria, but its optimal composition has not been established. OBJECTIVE In order to provide additional pathobiochemical insight and develop optimal LNAA treatment, several targeted LNAA supplements were investigated with respect to all 3 biochemical disturbances underlying brain dysfunction in phenylketonuria. DESIGN Pah-enu2 (PKU) mice received 1 of 5 different LNAA-supplemented diets beginning at postnatal day 45. Control groups included phenylketonuria mice receiving an isonitrogenic and isocaloric high-protein diet or the AIN-93M diet, and wild-type mice receiving the AIN-93M diet. After 6 wk, brain and plasma amino acid profiles and brain monoaminergic neurotransmitter concentrations were measured. RESULTS Brain Phe concentrations were most effectively reduced by supplementation of LNAAs, such as Leu and Ile, with a strong affinity for the LNAA transporter type 1. Brain non-Phe LNAAs could be restored on supplementation, but unbalanced LNAA supplementation further reduced brain concentrations of those LNAAs that were not (sufficiently) included in the LNAA supplement. To optimally ameliorate brain monoaminergic neurotransmitter concentrations, LNAA supplementation should include Tyr and Trp together with LNAAs that effectively reduce brain Phe concentrations. The requirement for Tyr supplementation is higher than it is for Trp, and the relative effect of brain Phe reduction is higher for serotonin than it is for dopamine and norepinephrine. CONCLUSION The study shows that all 3 biochemical disturbances underlying brain dysfunction in phenylketonuria can be targeted by specific LNAA supplements. The study thus provides essential information for the development of optimal LNAA supplementation as an alternative dietary treatment strategy to optimize neurocognitive outcome in patients with phenylketonuria.
Collapse
Affiliation(s)
- Danique van Vliet
- University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Groningen, Netherlands
| | - Vibeke M Bruinenberg
- Department of Molecular Neurobiology, University of Groningen, Groningen Institute for Evolutionary Life Sciences, Groningen, Netherlands
| | - Priscila N Mazzola
- University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Groningen, Netherlands.,Department of Molecular Neurobiology, University of Groningen, Groningen Institute for Evolutionary Life Sciences, Groningen, Netherlands
| | - Martijn Hjr van Faassen
- Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Pim de Blaauw
- Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Tiziana Pascucci
- Department of Psychology and Centro "Daniel Bovet," "La Sapienza" University, Fondazione Santa Lucia, Rome, Italy; and.,Fondazione Santa Lucia, Istituto di Ricovero e Cura a Carattere Scientifico, Rome, Italy
| | - Stefano Puglisi-Allegra
- Department of Psychology and Centro "Daniel Bovet," "La Sapienza" University, Fondazione Santa Lucia, Rome, Italy; and.,Fondazione Santa Lucia, Istituto di Ricovero e Cura a Carattere Scientifico, Rome, Italy
| | - Ido P Kema
- Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - M Rebecca Heiner-Fokkema
- Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Eddy A van der Zee
- Department of Molecular Neurobiology, University of Groningen, Groningen Institute for Evolutionary Life Sciences, Groningen, Netherlands
| | - Francjan J van Spronsen
- University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Groningen, Netherlands;
| |
Collapse
|
36
|
MacDonald A, Smith TA, de Silva S, Alam V, van Loon JMT. The personal burden for caregivers of children with phenylketonuria: A cross-sectional study investigating time burden and costs in the UK. Mol Genet Metab Rep 2016; 9:1-5. [PMID: 27622144 PMCID: PMC5009233 DOI: 10.1016/j.ymgmr.2016.08.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 08/24/2016] [Indexed: 12/19/2022] Open
Abstract
INTRODUCTION Management of phenylketonuria (PKU) is mainly achieved through strict dietary control that aims to limit the intake of phenylalanine (Phe). Adherence to this diet is burdensome due to the need for specially prepared low-Phe meals and regular monitoring of Phe concentrations. A UK cross-sectional study was conducted to identify the personal time and monetary burden associated with aspects of the PKU lifestyle for caregivers of children (aged < 18 years) living with PKU. METHODS Caregivers of pediatric patients with PKU attending one of four specialist metabolic centers in the UK were invited to participate in a questionnaire-based survey that evaluated different aspects of PKU management that could potentially present out-of-pocket costs (OOPCs) or time burden. Medical clinicians/dieticians provided patient information on PKU severity and an assessment of blood Phe control. RESULTS The survey was completed by 114 caregivers of 106 children having mild or moderate (n = 45; 39%) or classical (n = 60; 53%) PKU (severity data missing for n = 1), among whom 8 (8%) and 87 (82%) reported poorly controlled and controlled blood Phe status, respectively; Phe control data were missing for 11 children. Dietary management of PKU incurred a median time burden of > 19 h per week. OOPCs were incurred via attendance at PKU events, PKU-related equipment, and extra holiday expenditure. 21% of caregivers reduced their working hours (median 18.5 h/week) to care for their child, with a further 24% leaving their paid jobs completely. DISCUSSION AND CONCLUSIONS Dietary management of PKU is associated with a considerable time burden for caregivers of pediatric patients with PKU. A personal financial burden also arises from OOPCs and lost earnings.
Collapse
Affiliation(s)
- Anita MacDonald
- Dietetic Department, The Children's Hospital, Birmingham, B4 6NH, UK
| | | | | | | | | |
Collapse
|
37
|
Ney DM, Stroup BM, Clayton MK, Murali SG, Rice GM, Rohr F, Levy HL. Glycomacropeptide for nutritional management of phenylketonuria: a randomized, controlled, crossover trial. Am J Clin Nutr 2016; 104:334-45. [PMID: 27413125 PMCID: PMC4962165 DOI: 10.3945/ajcn.116.135293] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 06/10/2016] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND To prevent cognitive impairment, phenylketonuria requires lifelong management of blood phenylalanine (Phe) concentration with a low-Phe diet. The diet restricts intake of Phe from natural proteins in combination with traditional amino acid medical foods (AA-MFs) or glycomacropeptide medical foods (GMP-MFs) that contain primarily intact protein and a small amount of Phe. OBJECTIVE We investigated the efficacy and safety of a low-Phe diet combined with GMP-MFs or AA-MFs providing the same quantity of protein equivalents in free-living subjects with phenylketonuria. DESIGN This 2-stage, randomized crossover trial included 30 early-treated phenylketonuria subjects (aged 15-49 y), 20 with classical and 10 with variant phenylketonuria. Subjects consumed, in random order for 3 wk each, their usual low-Phe diet combined with AA-MFs or GMP-MFs. The treatments were separated by a 3-wk washout with AA-MFs. Fasting plasma amino acid profiles, blood Phe concentrations, food records, and neuropsychological tests were obtained. RESULTS The frequency of medical food intake was higher with GMP-MFs than with AA-MFs. Subjects rated GMP-MFs as more acceptable than AA-MFs and noted improved gastrointestinal symptoms and less hunger with GMP-MFs. ANCOVA indicated no significant mean ± SE increase in plasma Phe (62 ± 40 μmol/L, P = 0.136), despite a significant increase in Phe intake from GMP-MFs (88 ± 6 mg Phe/d, P = 0.026). AA-MFs decreased plasma Phe (-85 ± 40 μmol/L, P = 0.044) with stable Phe intake. Blood concentrations of Phe across time were not significantly different (AA-MFs = 444 ± 34 μmol/L, GMP-MFs = 497 ± 34 μmol/L), suggesting similar Phe control. Results of the Behavior Rating Inventory of Executive Function were not significantly different. CONCLUSIONS GMP-MFs provide a safe and acceptable option for the nutritional management of phenylketonuria. The greater acceptability and fewer side effects noted with GMP-MFs than with AA-MFs may enhance dietary adherence for individuals with phenylketonuria. This trial was registered at www.clinicaltrials.gov as NCT01428258.
Collapse
Affiliation(s)
| | | | - Murray K Clayton
- Statistics, and Plant Pathology, University of Wisconsin-Madison, Madison, WI
| | | | - Gregory M Rice
- Waisman Center and Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, WI; and
| | - Frances Rohr
- Division of Genetics and Genomics, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Harvey L Levy
- Division of Genetics and Genomics, Boston Children's Hospital, Harvard Medical School, Boston, MA
| |
Collapse
|
38
|
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: 71] [Impact Index Per Article: 8.9] [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/.
Collapse
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.
| |
Collapse
|
39
|
Pena MJ, de Almeida MF, van Dam E, Ahring K, Bélanger-Quintana A, Dokoupil K, Gokmen-Ozel H, Lammardo AM, MacDonald A, Robert M, Rocha JC. Protein substitutes for phenylketonuria in Europe: access and nutritional composition. Eur J Clin Nutr 2016; 70:785-9. [PMID: 27117930 DOI: 10.1038/ejcn.2016.54] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 02/01/2016] [Accepted: 02/26/2016] [Indexed: 12/11/2022]
Abstract
BACKGROUND/OBJECTIVES Protein substitutes (PS) are an essential component in the dietary management of phenylketonuria (PKU). PS are available as phenylalanine-free amino-acid mixtures (AAM), glycomacropeptide-based PS (GMP) and large neutral amino acids (LNAA). There is a lack of information regarding their availability in different countries and comparison of their nutritional composition is limited. The objectives of this study were to identify the number of PS available in different European countries and Turkey and to compare their nutritional composition. SUBJECTS/METHODS Members of the European Nutritionist Expert Panel on PKU (ENEP) (Portugal, Spain, Belgium, Italy, Germany, Netherlands, United Kingdom, Denmark and Turkey) provided data on PS available in each country. The nutritional composition of PS available in Portugal was analyzed. RESULTS The number of PS available in each country varied from 30 (Turkey) to 105 (Germany), with a median of 64. GMP was available only in Portugal, whereas LNAA was an option in Portugal, Italy, Turkey and Denmark. Some PS were designed for weaning. Many PS did not contain added fat and fiber. GMP contained the highest carbohydrate (CHO) and energy content as well as higher LNAA content compared with AAM. Only one AAM contained added fructo-oligosaccharides and galacto-oligosaccharides. AAM designed for the first year of life had the highest CHO, fat and LNAA contribution. Liquid AAM had lower CHO and fat contents compared with powdered AAM, but contained higher LNAA. CONCLUSIONS There was widely dissimilar numbers of PS available in different countries. Nutritional composition of different PS was variable and should be considered before prescription.
Collapse
Affiliation(s)
- M J Pena
- Centro de Genética Médica, Centro Hospitalar do Porto (CHP), Porto, Portugal
| | - M F de Almeida
- Centro de Genética Médica, Centro Hospitalar do Porto (CHP), Porto, Portugal.,Unit for Multidisciplinary Research in Biomedicine (UMIB), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), University of Porto, Porto, Portugal
| | - E van Dam
- University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Groningen, The Netherlands
| | - K Ahring
- Department of PKU, Kennedy Centre, Copenhagen University Hospital, Glostrup, Denmark
| | - A Bélanger-Quintana
- Unidad Enfermedades Metabolicas Servicio de Pediatria Hospital Ramon y Cajal, Madrid, Spain
| | - K Dokoupil
- Department of Metabolism and Nutrition, Dr von Hauner Children's Hospital, University of Munich, Munich, Germany
| | - H Gokmen-Ozel
- Department of Nutrition and Dietetics, Hacettepe University, Ankara, Turkey
| | - A M Lammardo
- Department of Pediatrics, San Paolo Hospital University of Milan, Milan, Italy
| | | | - M Robert
- Nutrition and Metabolism Unit, Hôpital Universitaire des Enfants Reine Fabiola, Brussels, Belgium
| | - J C Rocha
- Centro de Genética Médica, Centro Hospitalar do Porto (CHP), Porto, Portugal.,Faculdade de Ciências da Saúde, Universidade Fernando Pessoa, Porto, Portugal.,Center for Health Technology and Services Research (CINTESIS), Porto, Portugal
| |
Collapse
|
40
|
Abstract
Metabolic disorders comprise a large group of heterogeneous diseases ranging from very prevalent diseases such as diabetes mellitus to rare genetic disorders like Canavan Disease. Whether either of these diseases is amendable by gene therapy depends to a large degree on the knowledge of their pathomechanism, availability of the therapeutic gene, vector selection, and availability of suitable animal models. In this book chapter, we review three metabolic disorders of the central nervous system (CNS; Canavan Disease, Niemann-Pick disease and Phenylketonuria) to give examples for primary and secondary metabolic disorders of the brain and the attempts that have been made to use adeno-associated virus (AAV) based gene therapy for treatment. Finally, we highlight commonalities and obstacles in the development of gene therapy for metabolic disorders of the CNS exemplified by those three diseases.
Collapse
Affiliation(s)
- Dominic J Gessler
- University of Massachusetts Medical School, 368 Plantation Street, AS6-2049, Worcester, MA, 01605, USA
| | - Guangping Gao
- University of Massachusetts Medical School, 368 Plantation Street, AS6-2049, Worcester, MA, 01605, USA.
| |
Collapse
|
41
|
van Vliet D, Bruinenberg VM, Mazzola PN, van Faassen MHJR, de Blaauw P, Kema IP, Heiner-Fokkema MR, van Anholt RD, van der Zee EA, van Spronsen FJ. Large Neutral Amino Acid Supplementation Exerts Its Effect through Three Synergistic Mechanisms: Proof of Principle in Phenylketonuria Mice. PLoS One 2015; 10:e0143833. [PMID: 26624009 PMCID: PMC4666635 DOI: 10.1371/journal.pone.0143833] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 11/10/2015] [Indexed: 11/19/2022] Open
Abstract
Background Phenylketonuria (PKU) was the first disorder in which severe neurocognitive dysfunction could be prevented by dietary treatment. However, despite this effect, neuropsychological outcome in PKU still remains suboptimal and the phenylalanine-restricted diet is very demanding. To improve neuropsychological outcome and relieve the dietary restrictions for PKU patients, supplementation of large neutral amino acids (LNAA) is suggested as alternative treatment strategy that might correct all brain biochemical disturbances caused by high blood phenylalanine, and thereby improve neurocognitive functioning. Objective As a proof-of-principle, this study aimed to investigate all hypothesized biochemical treatment objectives of LNAA supplementation (normalizing brain phenylalanine, non-phenylalanine LNAA, and monoaminergic neurotransmitter concentrations) in PKU mice. Methods C57Bl/6 Pah-enu2 (PKU) mice and wild-type mice received a LNAA supplemented diet, an isonitrogenic/isocaloric high-protein control diet, or normal chow. After six weeks of dietary treatment, blood and brain amino acid and monoaminergic neurotransmitter concentrations were assessed. Results In PKU mice, the investigated LNAA supplementation regimen significantly reduced blood and brain phenylalanine concentrations by 33% and 26%, respectively, compared to normal chow (p<0.01), while alleviating brain deficiencies of some but not all supplemented LNAA. Moreover, LNAA supplementation in PKU mice significantly increased brain serotonin and norepinephrine concentrations from 35% to 71% and from 57% to 86% of wild-type concentrations (p<0.01), respectively, but not brain dopamine concentrations (p = 0.307). Conclusions This study shows that LNAA supplementation without dietary phenylalanine restriction in PKU mice improves brain biochemistry through all three hypothesized biochemical mechanisms. Thereby, these data provide proof-of-concept for LNAA supplementation as a valuable alternative dietary treatment strategy in PKU. Based on these results, LNAA treatment should be further optimized for clinical application with regard to the composition and dose of the LNAA supplement, taking into account all three working mechanisms of LNAA treatment.
Collapse
Affiliation(s)
- Danique van Vliet
- University of Groningen, University Medical Center Groningen, Beatrix Children’s Hospital, Groningen, The Netherlands
- University of Groningen, Center of Behavior and Neurosciences, Department of Molecular Neurobiology, Groningen, The Netherlands
| | - Vibeke M. Bruinenberg
- University of Groningen, Center of Behavior and Neurosciences, Department of Molecular Neurobiology, Groningen, The Netherlands
| | - Priscila N. Mazzola
- University of Groningen, University Medical Center Groningen, Beatrix Children’s Hospital, Groningen, The Netherlands
- University of Groningen, Center of Behavior and Neurosciences, Department of Molecular Neurobiology, Groningen, The Netherlands
| | - Martijn H. J. R. van Faassen
- University of Groningen, University Medical Center Groningen, Department of Laboratory Medicine, Groningen, The Netherlands
| | - Pim de Blaauw
- University of Groningen, University Medical Center Groningen, Department of Laboratory Medicine, Groningen, The Netherlands
| | - Ido P. Kema
- University of Groningen, University Medical Center Groningen, Department of Laboratory Medicine, Groningen, The Netherlands
| | - M. Rebecca Heiner-Fokkema
- University of Groningen, University Medical Center Groningen, Department of Laboratory Medicine, Groningen, The Netherlands
| | | | - Eddy A. van der Zee
- University of Groningen, Center of Behavior and Neurosciences, Department of Molecular Neurobiology, Groningen, The Netherlands
| | - Francjan J. van Spronsen
- University of Groningen, University Medical Center Groningen, Beatrix Children’s Hospital, Groningen, The Netherlands
- * E-mail:
| |
Collapse
|
42
|
Al Hafid N, Christodoulou J. Phenylketonuria: a review of current and future treatments. Transl Pediatr 2015; 4:304-17. [PMID: 26835392 PMCID: PMC4728993 DOI: 10.3978/j.issn.2224-4336.2015.10.07] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 10/26/2015] [Indexed: 01/16/2023] Open
Abstract
Phenylketonuria (PKU) is an autosomal recessive inborn error of metabolism caused by a deficiency in the hepatic enzyme phenylalanine hydroxylase (PAH). If left untreated, the main clinical feature is intellectual disability. Treatment, which includes a low Phe diet supplemented with amino acid formulas, commences soon after diagnosis within the first weeks of life. Although dietary treatment has been successful in preventing intellectual disability in early treated PKU patients, there are major issues with dietary compliance due to palatability of the diet. Other potential issues associated with dietary therapy include nutritional deficiencies especially vitamin D and B12. Suboptimal outcomes in cognitive and executive functioning have been reported in patients who adhere poorly to dietary therapy. There have been continuous attempts at improving the quality of medical foods including their palatability. Advances in dietary therapy such as the use of large neutral amino acids (LNAA) and glycomacropeptides (GMP; found within the whey fraction of bovine milk) have been explored. Gene therapy and enzyme replacement or substitution therapy have yielded more promising data in the recent years. In this review the current and possible future treatments for PKU are discussed.
Collapse
|
43
|
Dienel GA, Cruz NF. Biochemical, Metabolic, and Behavioral Characteristics of Immature Chronic Hyperphenylalanemic Rats. Neurochem Res 2015. [PMID: 26224289 DOI: 10.1007/s11064-015-1678-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Phenylketonuria and hyperphenylalanemia are inborn errors in metabolism of phenylalanine arising from defects in steps to convert phenylalanine to tyrosine. Phe accumulation causes severe mental retardation that can be prevented by timely identification of affected individuals and their placement on a Phe-restricted diet. In spite of many studies in patients and animal models, the basis for acquisition of mental retardation during the critical period of brain development is not adequately understood. All animal models for human disease have advantages and limitations, and characteristics common to different models are most likely to correspond to the disorder. This study established similar levels of Phe exposure in developing rats between 3 and 16 days of age using three models to produce chronic hyperphenylalanemia, and identified changes in brain amino acid levels common to all models that persist for ~16 h of each day. In a representative model, local rates of glucose utilization (CMRglc) were determined at 25-27 days of age, and only selective changes that appeared to depend on Phe exposure were observed. CMRglc was reduced in frontal cortex and thalamus and increased in hippocampus and globus pallidus. Behavioral testing to evaluate neuromuscular competence revealed poor performance in chronically-hyperphenylalanemic rats that persisted for at least 3 weeks after cessation of Phe injections and did not occur with mild or acute hyperphenylalanemia. Thus, the abnormal amino acid environment, including hyperglycinemia, in developing rat brain is associated with selective regional changes in glucose utilization and behavioral abnormalities that are not readily reversed after they are acquired.
Collapse
Affiliation(s)
- Gerald A Dienel
- Department of Neurology, University of Arkansas for Medical Sciences, 4301 W. Markham St., Mail Slot 500, Little Rock, AR, 72205, USA.
| | - Nancy F Cruz
- Department of Neurology, University of Arkansas for Medical Sciences, 4301 W. Markham St., Mail Slot 500, Little Rock, AR, 72205, USA
| |
Collapse
|
44
|
Kochhar JS, Chan SY, Ong PS, Kang L. Clinical therapeutics for phenylketonuria. Drug Deliv Transl Res 2015; 2:223-37. [PMID: 25787029 DOI: 10.1007/s13346-012-0067-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Phenylketonuria was amongst the first of the metabolic disorders to be characterised, exhibiting an inborn error in phenylalanine metabolism due to a functional deficit of the enzyme phenylalanine hydroxylase. It affects around 700,000 people around the globe. Mutations in the gene coding for hepatic phenylalanine hydroxylase cause this deficiency resulting in elevated plasma phenylalanine concentrations, leading to cognitive impairment, neuromotor disorders and related behavioural symptoms. Inception of low phenylalanine diet in the 1950s marked a revolution in the management of phenylketonuria and has since been a vital element of all therapeutic regimens. However, compliance to dietary therapy has been found difficult and newer supplement approaches are being examined. The current development of gene therapy and enzyme replacement therapeutics may offer promising alternatives for the management of phenylketonuria. This review outlines the pathological basis of phenylketonuria, various treatment regimes, their associated challenges and the future prospects of each approach. Briefly, novel drug delivery systems which can potentially deliver therapeutic strategies in phenylketonuria have been discussed.
Collapse
Affiliation(s)
- Jaspreet Singh Kochhar
- Department of Pharmacy, National University of Singapore, 18 Science Drive 4, Block S4 Level 2, Singapore, Singapore, 117543
| | | | | | | |
Collapse
|
45
|
Abstract
BACKGROUND Phenylketonuria is an inherited metabolic disorder characterised by an absence or deficiency of the enzyme phenylalanine hydroxylase. The aim of treatment is to lower blood phenylalanine concentrations to the recommended therapeutic range to prevent developmental delay and support normal growth. Current treatment consists of a low-phenylalanine diet in combination with a protein substitute which is free from or low in phenylalanine. Guidance regarding the use, dosage, and distribution of dosage of the protein substitute over a 24-hour period is unclear, and there is variation in recommendations among treatment centres. This is an update of a Cochrane review first published in 2005, and previously updated in 2008. OBJECTIVES To assess the benefits and adverse effects of protein substitute, its dosage, and distribution of dose in children and adults with phenylketonuria who are adhering to a low-phenylalanine diet. SEARCH METHODS We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register which consists of references identified from comprehensive electronic database searches and hand searches of relevant journals and abstract books of conference proceedings. We also contacted manufacturers of the phenylalanine-free and low-phenylalanine protein substitutes for any data from published and unpublished randomised controlled trials.Date of the most recent search of the Group's Inborn Errors of Metabolism Trials Register: 03 April 2014. SELECTION CRITERIA All randomised or quasi-randomised controlled trials comparing: any dose of protein substitute with no protein substitute; an alternative dosage; or the same dose, but given as frequent small doses throughout the day compared with the same total daily dose given as larger boluses less frequently. DATA COLLECTION AND ANALYSIS Both authors independently extracted data and assessed trial quality. MAIN RESULTS Three trials (69 participants) are included in this review. One trial investigated the use of protein substitute in 16 participants, while a further two trials investigated the dosage of protein substitute in a total of 53 participants. Due to issues with data presentation in each trial, described in full in the review, formal statistical analyses of the data were impossible. Investigators will be contacted for further information. AUTHORS' CONCLUSIONS No conclusions could be drawn about the short- or long-term use of protein substitute in phenylketonuria due to the lack of adequate or analysable trial data. Additional data and randomised controlled trials are needed to investigate the use of protein substitute in phenylketonuria. Until further evidence is available, current practice in the use of protein substitute should continue to be monitored with care.
Collapse
Affiliation(s)
- Sarah HL Yi
- Emory Genetics Metabolic Nutrition Program2165 N. Decatur RoadDecaturGeorgiaUSA30033
| | - Rani H Singh
- Emory University School of MedicineDepartment of Human Genetics2165 North Decatur RoadDecaturGeorgiaUSA30033
| | | |
Collapse
|
46
|
Sanayama Y, Matsumoto A, Shimojo N, Kohno Y, Nakaya H. Phenylalanine sensitive K562-D cells for the analysis of the biochemical impact of excess amino acid. Sci Rep 2014; 4:6941. [PMID: 25373594 PMCID: PMC4221789 DOI: 10.1038/srep06941] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 10/20/2014] [Indexed: 12/31/2022] Open
Abstract
Although it is recognized that the abnormal accumulation of amino acid is a cause of the symptoms in metabolic disease such as phenylketonuria (PKU), the relationship between disease severity and serum amino acid levels is not well understood due to the lack of experimental model. Here, we present a novel in vitro cellular model using K562-D cells that proliferate slowly in the presence of excessive amount of phenylalanine within the clinically observed range, but not phenylpyruvate. The increased expression of the L-type amino acid transporter (LAT2) and its adapter protein 4F2 heavy chain appeared to be responsible for the higher sensitivity to phenylalanine in K562-D cells. Supplementation with valine over phenylalanine effectively restored cell proliferation, although other amino acids did not improve K562-D cell proliferation over phenylalanine. Biochemical analysis revealed mammalian target of rapamycin complex (mTORC) as a terminal target of phenylalanine in K562-D cell proliferation, and supplementation of valine restored mTORC1 activity. Our results show that K562-D cell can be a potent tool for the investigation of PKU at the molecular level and to explore new therapeutic approaches to the disease.
Collapse
Affiliation(s)
- Yoshitami Sanayama
- 1] Department of Pharmacology, Graduate School of Medicine, Chiba University, Chiba [2] Department of Pediatrics, National Hospital Organization, Shimoshizu Hospital, Chiba
| | - Akio Matsumoto
- Department of Pharmacology, Graduate School of Medicine, Chiba University, Chiba
| | - Naoki Shimojo
- Department of Pediatrics, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Yoichi Kohno
- Department of Pediatrics, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Haruaki Nakaya
- Department of Pharmacology, Graduate School of Medicine, Chiba University, Chiba
| |
Collapse
|
47
|
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.
Collapse
|
48
|
Camp KM, Parisi MA, Acosta PB, Berry GT, Bilder DA, Blau N, Bodamer OA, Brosco JP, Brown CS, Burlina AB, Burton BK, Chang CS, Coates PM, Cunningham AC, Dobrowolski SF, Ferguson JH, Franklin TD, Frazier DM, Grange DK, Greene CL, Groft SC, Harding CO, Howell RR, Huntington KL, Hyatt-Knorr HD, Jevaji IP, Levy HL, Lichter-Konecki U, Lindegren ML, Lloyd-Puryear MA, Matalon K, MacDonald A, McPheeters ML, Mitchell JJ, Mofidi S, Moseley KD, Mueller CM, Mulberg AE, Nerurkar LS, Ogata BN, Pariser AR, Prasad S, Pridjian G, Rasmussen SA, Reddy UM, Rohr FJ, Singh RH, Sirrs SM, Stremer SE, Tagle DA, Thompson SM, Urv TK, Utz JR, van Spronsen F, Vockley J, Waisbren SE, Weglicki LS, White DA, Whitley CB, Wilfond BS, Yannicelli S, Young JM. Phenylketonuria Scientific Review Conference: state of the science and future research needs. Mol Genet Metab 2014; 112:87-122. [PMID: 24667081 DOI: 10.1016/j.ymgme.2014.02.013] [Citation(s) in RCA: 157] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 02/25/2014] [Accepted: 02/26/2014] [Indexed: 01/17/2023]
Abstract
New developments in the treatment and management of phenylketonuria (PKU) as well as advances in molecular testing have emerged since the National Institutes of Health 2000 PKU Consensus Statement was released. An NIH State-of-the-Science Conference was convened in 2012 to address new findings, particularly the use of the medication sapropterin to treat some individuals with PKU, and to develop a research agenda. Prior to the 2012 conference, five working groups of experts and public members met over a 1-year period. The working groups addressed the following: long-term outcomes and management across the lifespan; PKU and pregnancy; diet control and management; pharmacologic interventions; and molecular testing, new technologies, and epidemiologic considerations. In a parallel and independent activity, an Evidence-based Practice Center supported by the Agency for Healthcare Research and Quality conducted a systematic review of adjuvant treatments for PKU; its conclusions were presented at the conference. The conference included the findings of the working groups, panel discussions from industry and international perspectives, and presentations on topics such as emerging treatments for PKU, transitioning to adult care, and the U.S. Food and Drug Administration regulatory perspective. Over 85 experts participated in the conference through information gathering and/or as presenters during the conference, and they reached several important conclusions. The most serious neurological impairments in PKU are preventable with current dietary treatment approaches. However, a variety of more subtle physical, cognitive, and behavioral consequences of even well-controlled PKU are now recognized. The best outcomes in maternal PKU occur when blood phenylalanine (Phe) concentrations are maintained between 120 and 360 μmol/L before and during pregnancy. The dietary management treatment goal for individuals with PKU is a blood Phe concentration between 120 and 360 μmol/L. The use of genotype information in the newborn period may yield valuable insights about the severity of the condition for infants diagnosed before maximal Phe levels are achieved. While emerging and established genotype-phenotype correlations may transform our understanding of PKU, establishing correlations with intellectual outcomes is more challenging. Regarding the use of sapropterin in PKU, there are significant gaps in predicting response to treatment; at least half of those with PKU will have either minimal or no response. A coordinated approach to PKU treatment improves long-term outcomes for those with PKU and facilitates the conduct of research to improve diagnosis and treatment. New drugs that are safe, efficacious, and impact a larger proportion of individuals with PKU are needed. However, it is imperative that treatment guidelines and the decision processes for determining access to treatments be tied to a solid evidence base with rigorous standards for robust and consistent data collection. The process that preceded the PKU State-of-the-Science Conference, the conference itself, and the identification of a research agenda have facilitated the development of clinical practice guidelines by professional organizations and serve as a model for other inborn errors of metabolism.
Collapse
Affiliation(s)
- Kathryn M Camp
- Office of Dietary Supplements, National Institutes of Health, Bethesda, MD 20982, USA.
| | - Melissa A Parisi
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
| | | | - Gerard T Berry
- Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
| | - Deborah A Bilder
- Department of Psychiatry, University of Utah, Salt Lake City, UT 84108, USA.
| | - Nenad Blau
- University Children's Hospital, Heidelberg, Germany; University Children's Hospital, Zürich, Switzerland.
| | - Olaf A Bodamer
- University of Miami Miller School of Medicine, Miami, FL 33136, USA.
| | - Jeffrey P Brosco
- University of Miami Mailman Center for Child Development, Miami, FL 33101, USA.
| | | | | | - Barbara K Burton
- Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, IL 60611, USA.
| | - Christine S Chang
- Agency for Healthcare Research and Quality, Rockville, MD 20850, USA.
| | - Paul M Coates
- Office of Dietary Supplements, National Institutes of Health, Bethesda, MD 20982, USA.
| | - Amy C Cunningham
- Tulane University Medical School, Hayward Genetics Center, New Orleans, LA 70112, USA.
| | | | - John H Ferguson
- Office of Rare Diseases Research, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20982, USA.
| | | | | | - Dorothy K Grange
- Washington University School of Medicine, St. Louis Children's Hospital, St. Louis, MO 63110, USA.
| | - Carol L Greene
- University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | - Stephen C Groft
- Office of Rare Diseases Research, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20982, USA.
| | - Cary O Harding
- Oregon Health & Science University, Portland, OR 97239, USA.
| | - R Rodney Howell
- University of Miami Miller School of Medicine, Miami, FL 33136, USA.
| | | | - Henrietta D Hyatt-Knorr
- Office of Rare Diseases Research, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20982, USA.
| | - Indira P Jevaji
- Office of Research on Women's Health, National Institutes of Health, Bethesda, MD 20817, USA.
| | - Harvey L Levy
- Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
| | - Uta Lichter-Konecki
- George Washington University, Children's National Medical Center, Washington, DC 20010, USA.
| | | | | | | | | | - Melissa L McPheeters
- Vanderbilt Evidence-based Practice Center, Institute for Medicine and Public Health, Nashville, TN 37203, USA.
| | - John J Mitchell
- McGill University Health Center, Montreal, Quebec H3H 1P3, Canada.
| | - Shideh Mofidi
- Maria Fareri Children's Hospital of Westchester Medical Center, Valhalla, NY 10595, USA.
| | - Kathryn D Moseley
- University of Southern California Keck School of Medicine, Los Angeles, CA 90033, USA.
| | - Christine M Mueller
- Office of Orphan Products Development, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA.
| | - Andrew E Mulberg
- Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA.
| | - Lata S Nerurkar
- Office of Rare Diseases Research, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20982, USA.
| | - Beth N Ogata
- University of Washington, Seattle, WA 98195, USA.
| | - Anne R Pariser
- Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA.
| | - Suyash Prasad
- BioMarin Pharmaceutical Inc., San Rafael, CA 94901, USA.
| | - Gabriella Pridjian
- Tulane University Medical School, Hayward Genetics Center, New Orleans, LA 70112, USA.
| | | | - Uma M Reddy
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
| | | | | | - Sandra M Sirrs
- Vancouver General Hospital, University of British Columbia, Vancouver V5Z 1M9, Canada.
| | | | - Danilo A Tagle
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Susan M Thompson
- The Children's Hospital at Westmead, Sydney, NSW 2145, Australia.
| | - Tiina K Urv
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Jeanine R Utz
- University of Minnesota, Minneapolis, MN 55455, USA.
| | - Francjan van Spronsen
- University of Groningen, University Medical Center of Groningen, Beatrix Children's Hospital, Netherlands.
| | - Jerry Vockley
- University of Pittsburgh, Pittsburgh, PA 15224, USA.
| | - Susan E Waisbren
- Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
| | - Linda S Weglicki
- National Institute of Nursing Research, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Desirée A White
- Department of Psychology, Washington University, St. Louis, MO 63130, USA.
| | | | - Benjamin S Wilfond
- Seattle Children's Research Institute, University of Washington School of Medicine, Seattle, WA 98101, USA.
| | | | - Justin M Young
- The Young Face, Facial Plastic and Reconstructive Surgery, Cumming, GA 30041, USA.
| |
Collapse
|
49
|
Abstract
Phenylketonuria (PKU) is an inborn error of metabolism of the amino acid phenylalanine. It is an autosomal recessive disorder with a rate of incidence of 1 in 10,000 in Caucasian populations. Mutations in the phenylalanine hydroxylase (PAH) gene are the major cause of PKU, due to the loss of the catalytic activity of the enzyme product PAH. Newborn screening for PKU allows early intervention, avoiding irreparable neurological damage and intellectual disability that would arise from untreated PKU. The current primary treatment of PKU is the limitation of dietary protein intake, which in the long term may be associated with poor compliance in some cases and other health problems due to malnutrition. The only alternative therapy currently approved is the supplementation of BH4, the requisite co-factor of PAH, in the orally-available form of sapropterin dihydrochloride. This treatment is not universally available, and is only effective for a proportion (estimated 30%) of PKU patients. Research into novel therapies for PKU has taken many different approaches to address the lack of PAH activity at the core of this disorder: enzyme replacement via virus-mediated gene transfer, transplantation of donor liver and recombinant PAH protein, enzyme substitution using phenylalanine ammonia lyase (PAL) to provide an alternative pathway for the metabolism of phenylalanine, and restoration of native PAH activity using chemical chaperones and nonsense read-through agents. It is hoped that continuing efforts into these studies will translate into a significant improvement in the physical outcome, as well as quality of life, for patients with PKU.
Collapse
Affiliation(s)
- Gladys Ho
- 1 Genetic Metabolic Disorders Research Unit; 2 Disciplines of Paediatrics and Child Health and 3 Genetic Medicine, University of Sydney, Sydney, NSW, Australia ; 4 Genetic Metabolic Disorders Service, Western Sydney Genetics Program, Children's Hospital at Westmead, Sydney, NSW, Australia
| | - John Christodoulou
- 1 Genetic Metabolic Disorders Research Unit; 2 Disciplines of Paediatrics and Child Health and 3 Genetic Medicine, University of Sydney, Sydney, NSW, Australia ; 4 Genetic Metabolic Disorders Service, Western Sydney Genetics Program, Children's Hospital at Westmead, Sydney, NSW, Australia
| |
Collapse
|
50
|
Singh RH, Rohr F, Frazier D, Cunningham A, Mofidi S, Ogata B, Splett PL, Moseley K, Huntington K, Acosta PB, Vockley J, Van Calcar SC. Recommendations for the nutrition management of phenylalanine hydroxylase deficiency. Genet Med 2014; 16:121-31. [PMID: 24385075 PMCID: PMC3918542 DOI: 10.1038/gim.2013.179] [Citation(s) in RCA: 115] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 10/16/2013] [Indexed: 11/09/2022] Open
Abstract
The effectiveness of a phenylalanine-restricted diet to improve the outcome of individuals with phenylalanine hydroxylase deficiency (OMIM no. 261600) has been recognized since the first patients were treated 60 years ago. However, the treatment regime is complex, costly, and often difficult to maintain for the long term. Improvements and refinements in the diet for phenylalanine hydroxylase deficiency have been made over the years, and adjunctive therapies have proven to be successful for certain patients. Yet evidence-based guidelines for managing phenylalanine hydroxylase deficiency, optimizing outcomes, and addressing all available therapies are lacking. Thus, recommendations for nutrition management were developed using evidence from peer-reviewed publications, gray literature, and consensus surveys. The areas investigated included choice of appropriate medical foods, integration of adjunctive therapies, treatment during pregnancy, monitoring of nutritional and clinical markers, prevention of nutrient deficiencies, providing of access to care, and compliance strategies. This process has not only provided assessment and refinement of current nutrition management and monitoring recommendations but also charted a direction for future studies. This document serves as a companion to the concurrently published American College of Medical Genetics and Genomics guideline for the medical treatment of phenylalanine hydroxylase deficiency.
Collapse
Affiliation(s)
- Rani H. Singh
- Division of Medical Genetics, Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Fran Rohr
- Division of Genetics and Metabolism, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Dianne Frazier
- Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Amy Cunningham
- Hayward Genetics Center, Tulane University School of Medicine, New Orleans, Louisiana, USA
| | - Shideh Mofidi
- Inherited Metabolic Disease Center, Maria Fareri Children's Hospital, Westchester Medical Center, New York Medical College, Valhalla, New York, USA
| | - Beth Ogata
- Department of Pediatrics, University of Washington, Seattle, Washington, USA
| | | | - Kathryn Moseley
- Department of Pediatrics, University of Southern California Medical Center, Los Angeles, California, USA
| | - Kathleen Huntington
- Metabolic Clinic, Institute for Development and Disability, Oregon Health Science University, Portland, Oregon, USA
| | | | - Jerry Vockley
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Department of Human Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Sandra C. Van Calcar
- Division of Genetics and Metabolism, Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
| |
Collapse
|