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Trefz F, Frauendienst-Egger G, Dienel G, Cannet C, Schmidt-Mader B, Haas D, Blau N, Himmelreich N, Spraul M, Freisinger P, Dobrowolski S, Berg D, Pilotto A. Does hyperphenylalaninemia induce brain glucose hypometabolism? Cerebral spinal fluid findings in treated adult phenylketonuric patients. Mol Genet Metab 2024; 142:108464. [PMID: 38537426 DOI: 10.1016/j.ymgme.2024.108464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 03/21/2024] [Accepted: 03/22/2024] [Indexed: 05/08/2024]
Abstract
Despite numerous studies in human patients and animal models for phenylketonuria (PKU; OMIM#261600), the pathophysiology of PKU and the underlying causes of brain dysfunction and cognitive problems in PKU patients are not well understood. In this study, lumbar cerebral spinal fluid (CSF) was obtained immediately after blood sampling from early-treated adult PKU patients who had fasted overnight. Metabolite and amino acid concentrations in the CSF of PKU patients were compared with those of non-PKU controls. The CSF concentrations and CSF/plasma ratios for glucose and lactate were found to be below normal, similar to what has been reported for glucose transporter1 (GLUT1) deficiency patients who exhibit many of the same clinical symptoms as untreated PKU patients. CSF glucose and lactate levels were negatively correlated with CSF phenylalanine (Phe), while CSF glutamine and glutamate levels were positively correlated with CSF Phe levels. Plasma glucose levels were negatively correlated with plasma Phe concentrations in PKU subjects, which partly explains the reduced CSF glucose concentrations. Although brain glucose concentrations are unlikely to be low enough to impair brain glucose utilization, it is possible that the metabolism of Phe in the brain to produce phenyllactate, which can be transported across the blood-brain barrier to the blood, may consume glucose and/or lactate to generate the carbon backbone for glutamate. This glutamate is then converted to glutamine and carries the Phe-derived ammonia from the brain to the blood. While this mechanism remains to be tested, it may explain the correlations of CSF glutamine, glucose, and lactate concentrations with CSF Phe.
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Affiliation(s)
- Friedrich Trefz
- Heidelberg University, Medical Faculty of Heidelberg, Center for Child and Adolescent Medicine, Division of Child Neurology and Metabolic Medicine, Heidelberg, Germany.
| | | | - Gerald Dienel
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, AR, United States; Department of Cell Biology and Physiology, University of New Mexico, Albuquerque, NM, United States
| | | | - Brigitte Schmidt-Mader
- Heidelberg University, Medical Faculty of Heidelberg, Center for Child and Adolescent Medicine, Division of Child Neurology and Metabolic Medicine, Heidelberg, Germany
| | - Dorothea Haas
- Heidelberg University, Medical Faculty of Heidelberg, Center for Child and Adolescent Medicine, Division of Child Neurology and Metabolic Medicine, Heidelberg, Germany
| | - Nenad Blau
- University Children's Hospital Zürich, Zürich, Switzerland
| | | | | | - Peter Freisinger
- Klinikum Reutlingen, Department of Pediatrics, Reutlingen, Germany
| | - Steven Dobrowolski
- Department of Pathology, University of Pittsburgh, School of Medicine, Pittsburgh, PA 15224, United States
| | - Daniela Berg
- Department of Neurology, University Hospital of Schleswig-Holstein, Kiel, Germany
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Wang MW, Wu CJ, Zhang ZQ. Neurological and imaging phenotypes of adults with untreated phenylketonuria: new cases and literature review. J Neurol 2023:10.1007/s00415-023-11760-9. [PMID: 37162580 DOI: 10.1007/s00415-023-11760-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 05/02/2023] [Accepted: 05/04/2023] [Indexed: 05/11/2023]
Abstract
OBJECTIVES Phenylketonuria (PKU) is the most prevalent congenital disease of amino acid metabolism. Neurological manifestations usually complicate PKU in untreated adult patients. This study describes neurological and imaging phenotypes of adult patients with untreated PKU. METHODS We investigated a cohort of 320 unrelated adult patients with suspected genetic leukoencephalopathies using whole-exome sequencing (WES). We analyzed the phenotypic features of adult PKU patients in our cohort and summarized cases reported in the literature. RESULTS We identified 10 patients in our cohort and 12 patients in the literature, who presented with neurological manifestations and were diagnosed with PKU in adulthood. Approximately 60% of these patients had onset of clinical features in adulthood. The most common neurological symptoms of patients presenting in adulthood were cognitive disturbance and spastic paralysis, followed by vision loss, cerebellar ataxia, weakness of limbs, and seizure. This differed from that of patients presenting with PKU features in childhood, who consistently had mental retardation with various neurological complications emerging during a broad age range. Imaging findings were similar between patients presenting with clinical features in childhood compared with adulthood, comprising symmetric periventricular white matter hyperintense on T2-weighted imaging and diffusion-weighted imaging predominantly in the parietal and occipital lobes. Also, normal brain imaging and diffuse leukoencephalopathies were observed in both patient groups. CONCLUSION PKU with clinical features presenting in adulthood is an atypical subtype and should be considered during diagnosis of adults with neurological symptoms and leukoencephalopathy. DWI seems to be most helpful to distinguish patients with PKU. Additionally, we demonstrate that PKU constitutes a part (3.1%) of adult genetic leukoencephalopathies.
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Affiliation(s)
- Meng-Wen Wang
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, 350005, China
| | - Chu-Jun Wu
- Department of Neurology, Beijing Tiantan Hospital, National Clinical Research Center for Neurological Diseases, Capital Medical University, No.119 South 4Th Ring West Road, Fengtai District, Beijing, 100070, China
- China National Clinical Research Center for Neurological Diseases, Beijing, 100070, China
| | - Zai-Qiang Zhang
- Department of Neurology, Beijing Tiantan Hospital, National Clinical Research Center for Neurological Diseases, Capital Medical University, No.119 South 4Th Ring West Road, Fengtai District, Beijing, 100070, China.
- China National Clinical Research Center for Neurological Diseases, Beijing, 100070, China.
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Merkel M, Berg D, Brüggemann N, Classen J, Mainka T, Zittel S, Muntau AC. Characterisation and differential diagnosis of neurological complications in adults with phenylketonuria: literature review and expert opinion. J Neurol 2023:10.1007/s00415-023-11703-4. [PMID: 37081197 DOI: 10.1007/s00415-023-11703-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 03/31/2023] [Accepted: 04/01/2023] [Indexed: 04/22/2023]
Abstract
OBJECTIVE Phenylketonuria (PKU) is a rare inherited metabolic disorder characterised by elevated phenylalanine (Phe) concentrations that can exert neurotoxic effects if untreated or upon treatment discontinuation. This systematic review supported by expert opinion aims to raise awareness among the neurological community on neurological complications experienced by adults with PKU (AwPKU). METHODS The PubMed database was searched for articles on neurological signs and symptoms in AwPKU published before March 2022. In addition, two virtual advisory boards were held with a panel of seven neurologists and two metabolic physicians from Germany and Austria. Findings are supported by three illustrative patient cases. RESULTS Thirty-nine articles were included. Despite early diagnosis and treatment, neurological signs and symptoms (e.g. ataxia, brisk tendon reflexes, tremor, visual impairment) can emerge in adulthood, especially if treatment has been discontinued after childhood. In PKU, late-onset neurological deficits often co-occur with cognitive impairment and psychiatric symptoms, all of which can be completely or partially reversed through resumption of treatment. CONCLUSION Ideally, neurologists should be part of the PKU multidisciplinary team, either to bring lost to follow-up patients back to clinic or to manage symptoms in referred patients, considering that symptoms are often reversible upon regaining metabolic control. The current findings have been combined in a leaflet that will be disseminated among neurologists in Germany and Austria to create awareness.
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Affiliation(s)
- Martin Merkel
- Endokrinologikum Hamburg, Lornsenstraße 6, 22767, Hamburg, Germany.
- Asklepios Campus Hamburg, Semmelweis University, Hamburg, Germany.
| | - Daniela Berg
- Department of Neurology, Christian-Albrechts University, Kiel, Germany
| | | | - Joseph Classen
- Department of Neurology, Leipzig University Medical Center, Leipzig, Germany
| | - Tina Mainka
- Department of Neurology, Charité University Medicine Berlin, Berlin, Germany
- Berlin Institute of Health at Charité Universitätsmedizin Berlin, BIH Biomedical Innovation Academy, BIH Charité Clinician Scientist Program, Berlin, Germany
| | - Simone Zittel
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ania C Muntau
- University Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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Thau-Zuchman O, Pallier PN, Savelkoul PJM, Kuipers AAM, Verkuyl JM, Michael-Titus AT. High phenylalanine concentrations induce demyelination and microglial activation in mouse cerebellar organotypic slices. Front Neurosci 2022; 16:926023. [PMID: 36248632 PMCID: PMC9559601 DOI: 10.3389/fnins.2022.926023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 09/05/2022] [Indexed: 11/29/2022] Open
Abstract
Phenylketonuria (PKU) is an inborn error of metabolism. Mutations in the enzyme phenylalanine hydroxylase (PAH)-encoding gene lead to a decreased metabolism of the amino acid phenylalanine (Phe). The deficiency in PAH increases Phe levels in blood and brain. Accumulation of Phe can lead to delayed development, psychiatric problems and cognitive impairment. White matter (WM) damage is a neuropathological hallmark of PKU and can be seen even in early detected and treated PKU patients. The mechanisms linking high Phe concentrations to WM abnormalities remain unclear. We tested the effects of high Phe concentrations on myelin in three in vitro models of increasing complexity: two simple cell culture models and one model that preserves local brain tissue architecture, a cerebellar organotypic slice culture prepared from postnatal day (P) 8 CD-1 mice. Various Phe concentrations (0.1–10 mM) and durations of exposure were tested. We found no toxic effect of high Phe in the cell culture models. On the contrary, the treatment promoted the maturation of oligodendrocytes, particularly at the highest, non-physiological Phe concentrations. Exposure of cerebellar organotypic slices to 2.4 mM Phe for 21 days in vitro (DIV), but not 7 or 10 DIV, resulted in a significant decrease in myelin basic protein (MBP), calbindin-stained neurites, and neurites co-stained with MBP. Following exposure to a toxic concentration of Phe, a switch to the control medium for 7 days did not lead to remyelination, while very active remyelination was seen in slices following demyelination with lysolecithin. An enhanced number of microglia, displaying an activated type morphology, was seen after exposure of the slices to 2.4 mM Phe for 10 or 21 DIV. The results suggest that prolonged exposure to high Phe concentrations can induce microglial activation preceding significant disruption of myelin.
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Affiliation(s)
- Orli Thau-Zuchman
- Centre for Neuroscience, Surgery and Trauma, Barts and The London School of Medicine and Dentistry, The Blizard Institute, Queen Mary University of London, London, United Kingdom
| | - Patrick N. Pallier
- Centre for Neuroscience, Surgery and Trauma, Barts and The London School of Medicine and Dentistry, The Blizard Institute, Queen Mary University of London, London, United Kingdom
- *Correspondence: Patrick N. Pallier,
| | | | | | | | - Adina T. Michael-Titus
- Centre for Neuroscience, Surgery and Trauma, Barts and The London School of Medicine and Dentistry, The Blizard Institute, Queen Mary University of London, London, United Kingdom
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Dijkstra AM, van Vliet N, van Vliet D, Romani C, Huijbregts SCJ, van der Goot E, Hovens IB, van der Zee EA, Kema IP, Heiner-Fokkema MR, van Spronsen FJ. Correlations of blood and brain biochemistry in phenylketonuria: Results from the Pah-enu2 PKU mouse. Mol Genet Metab 2021; 134:250-256. [PMID: 34656426 DOI: 10.1016/j.ymgme.2021.09.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 09/12/2021] [Accepted: 09/18/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND In phenylketonuria (PKU), treatment monitoring is based on frequent blood phenylalanine (Phe) measurements, as this is the predictor of neurocognitive and behavioural outcome by reflecting brain Phe concentrations and brain biochemical changes. Despite clinical studies describing the relevance of blood Phe to outcome in PKU patients, blood Phe does not explain the variance in neurocognitive and behavioural outcome completely. METHODS In a PKU mouse model we investigated 1) the relationship between plasma Phe and brain biochemistry (Brain Phe and monoaminergic neurotransmitter concentrations), and 2) whether blood non-Phe Large Neutral Amino Acids (LNAA) would be of additional value to blood Phe concentrations to explain brain biochemistry. To this purpose, we assessed blood amino acid concentrations and brain Phe as well as monoaminergic neurotransmitter levels in in 114 Pah-Enu2 mice on both B6 and BTBR backgrounds using (multiple) linear regression analyses. RESULTS Plasma Phe concentrations were strongly correlated to brain Phe concentrations, significantly negatively correlated to brain serotonin and norepinephrine concentrations and only weakly correlated to brain dopamine concentrations. From all blood markers, Phe showed the strongest correlation to brain biochemistry in PKU mice. Including non-Phe LNAA concentrations to the multiple regression model, in addition to plasma Phe, did not help explain brain biochemistry. CONCLUSION This study showed that blood Phe is still the best amino acid predictor of brain biochemistry in PKU. Nevertheless, neurocognitive and behavioural outcome cannot fully be explained by blood or brain Phe concentrations, necessitating a search for other additional parameters. TAKE-HOME MESSAGE Blood Phe is still the best amino acid predictor of brain biochemistry in PKU. Nevertheless, neurocognitive and behavioural outcome cannot fully be explained by blood or brain Phe concentrations, necessitating a search for other additional parameters.
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Affiliation(s)
- Allysa M Dijkstra
- University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Groningen, the Netherlands
| | - Ninke van Vliet
- University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Groningen, the Netherlands
| | - Danique van Vliet
- University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Groningen, the Netherlands
| | - Cristina Romani
- School of Life and Health Sciences, Aston University, Birmingham, UK
| | - Stephan C J Huijbregts
- Department of Clinical Child and Adolescent Studies-Neurodevelopmental Disorders, Faculty of Social Sciences, Leiden University, Leiden, the Netherlands
| | - Els van der Goot
- University of Groningen, Groningen Institute for Evolutionary Life Sciences (GELIFES), Department of Molecular Neurobiology, Groningen, the Netherlands
| | - Iris B Hovens
- University of Groningen, Groningen Institute for Evolutionary Life Sciences (GELIFES), Department of Molecular Neurobiology, Groningen, the Netherlands
| | - Eddy A van der Zee
- University of Groningen, Groningen Institute for Evolutionary Life Sciences (GELIFES), Department of Molecular Neurobiology, 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
| | - Francjan J van Spronsen
- University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Groningen, the Netherlands.
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Abstract
Magnetic resonance spectroscopy (MRS), being able to identify and measure some brain components (metabolites) in pathologic lesions and in normal-appearing tissue, offers a valuable additional diagnostic tool to assess several pediatric neurological diseases. In this review we will illustrate the basic principles and clinical applications of brain proton (H1; hydrogen) MRS (H1MRS), by now the only MRS method widely available in clinical practice. Performing H1MRS in the brain is inherently less complicated than in other tissues (e.g., liver, muscle), in which spectra are heavily affected by magnetic field inhomogeneities, respiration artifacts, and dominating signals from the surrounding adipose tissues. H1MRS in pediatric neuroradiology has some advantages over acquisitions in adults (lack of motion due to children sedation and lack of brain iron deposition allow optimal results), but it requires a deep knowledge of pediatric pathologies and familiarity with the developmental changes in spectral patterns, particularly occurring in the first two years of life. Examples from our database, obtained mainly from a 1.5 Tesla clinical scanner in a time span of 15 years, will demonstrate the efficacy of H1MRS in the diagnosis of a wide range of selected pediatric pathologies, like brain tumors, infections, neonatal hypoxic-ischemic encephalopathy, metabolic and white matter disorders.
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Affiliation(s)
- Roberto Liserre
- Department of Radiology, Neuroradiology Unit, ASST Spedali Civili University Hospital, Brescia, Italy
| | - Lorenzo Pinelli
- Department of Radiology, Neuroradiology Unit, ASST Spedali Civili University Hospital, Brescia, Italy
| | - Roberto Gasparotti
- Neuroradiology Unit, Department of Medical-Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, Brescia, Italy
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Trepp R, Muri R, Abgottspon S, Bosanska L, Hochuli M, Slotboom J, Rummel C, Kreis R, Everts R. Impact of phenylalanine on cognitive, cerebral, and neurometabolic parameters in adult patients with phenylketonuria (the PICO study): a randomized, placebo-controlled, crossover, noninferiority trial. Trials 2020; 21:178. [PMID: 32054509 PMCID: PMC7020385 DOI: 10.1186/s13063-019-4022-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 12/20/2019] [Indexed: 01/05/2023] Open
Abstract
Background The population of adult patients with early-treated phenylketonuria (PKU) following newborn screening is growing substantially. The ideal target range of blood phenylalanine (Phe) levels in adults outside pregnancy is a matter of debate. Therefore, prospective intervention studies are needed to evaluate the effects of an elevated Phe concentration on cognition and structural, functional, and neurometabolic parameters of the brain. Methods The PICO (Phenylalanine and Its Impact on Cognition) Study evaluates the effect of a 4-week Phe load on cognition and cerebral parameters in adults with early-treated PKU in a double-blind, randomized, placebo-controlled, crossover, noninferiority trial. Participants Thirty adult patients with early-treated PKU and 30 healthy controls comparable to patients with regard to age, sex, and educational level will be recruited from the University Hospitals Bern and Zurich, Switzerland. Patients are eligible for the study if they are 18 years of age or older and had PKU diagnosed after a positive newborn screening and were treated with a Phe-restricted diet starting within the first 30 days of life. Intervention: The cross-over intervention consists of 4-week oral Phe or placebo administration in patients with PKU. The study design mimics a Phe-restricted and a Phe-unrestricted diet using a double-blinded, placebo-controlled approach. Objectives The primary objective of the PICO Study is to prospectively assess whether a temporarily elevated Phe level influences cognitive performance (working memory assessed with a n-back task) in adults with early-treated PKU. As a secondary objective, the PICO Study will elucidate the cerebral (fMRI, neural activation during a n-back task; rsfMRI, functional connectivity at rest; DTI, white matter integrity; and ASL, cerebral blood flow) and neurometabolic mechanisms (cerebral Phe level) that accompany changes in Phe concentration. Cognition, and structural and functional parameters of the brain of adult patients with early-treated PKU will be cross-sectionally compared to healthy controls. All assessments will take place at the University Hospital Bern, Switzerland. Randomization Central randomization will be used to assign participants to the different treatment arms with age, sex, and center serving as the stratification factors. Randomization lists will be generated by an independent statistician. Blinding: All trial personnel other than the statistician generating the randomization list and the personnel at the facility preparing the interventional product are blinded to the assigned treatment. Discussion Using a combination of neuropsychological and neuroimaging data, the PICO Study will considerably contribute to improve the currently insufficient level of evidence on how adult patients with early-treated PKU should be managed. Trial registration The study is registered at clinicaltrials.gov (NCT03788343) on the 27th of December 2018, at kofam.ch (SNCTP000003117) on the 17th of December 2018, and on the International Clinical Trials Registry Platform of the WHO.
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Affiliation(s)
- Roman Trepp
- Department of Diabetes, Endocrinology, Nutritional Medicine and Metabolism, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland
| | - Raphaela Muri
- Department of Diabetes, Endocrinology, Nutritional Medicine and Metabolism, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland.,Support Center for Advanced Neuroimaging (SCAN), University Institute of Diagnostic and Interventional Neuroradiology, Inselspital, Bern University Hospital, Bern, Switzerland
| | - Stephanie Abgottspon
- Department of Diabetes, Endocrinology, Nutritional Medicine and Metabolism, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland
| | - Lenka Bosanska
- Department of Diabetes, Endocrinology, Nutritional Medicine and Metabolism, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland
| | - Michel Hochuli
- Department of Diabetes, Endocrinology, Nutritional Medicine and Metabolism, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland
| | - Johannes Slotboom
- Support Center for Advanced Neuroimaging (SCAN), University Institute of Diagnostic and Interventional Neuroradiology, Inselspital, Bern University Hospital, Bern, Switzerland
| | - Christian Rummel
- Support Center for Advanced Neuroimaging (SCAN), University Institute of Diagnostic and Interventional Neuroradiology, Inselspital, Bern University Hospital, Bern, Switzerland
| | - Roland Kreis
- Magnetic Resonance Methodology Unit, Department of Biomedical Research & Institute of Interventional, Diagnostic and Pediatric Radiology, University of Bern, Bern, Switzerland
| | - Regula Everts
- Department of Diabetes, Endocrinology, Nutritional Medicine and Metabolism, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland. .,Division of Neuropediatrics, Development and Rehabilitation, Children's University Hospital, Inselspital, Bern University Hospital, Bern, Switzerland.
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Burlina AP, Lachmann RH, Manara R, Cazzorla C, Celato A, van Spronsen FJ, Burlina A. The neurological and psychological phenotype of adult patients with early-treated phenylketonuria: A systematic review. J Inherit Metab Dis 2019; 42:209-219. [PMID: 30690773 DOI: 10.1002/jimd.12065] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 01/21/2019] [Indexed: 11/11/2022]
Abstract
Newborn screening for phenylketonuria (PKU) and early introduction of dietary therapy has been remarkably successful in preventing the severe neurological features of PKU, including mental retardation and epilepsy. However, concerns remain that long-term outcome is still suboptimal, particularly in adult patients who are no longer on strict phenylalanine-restricted diets. With our systematic literature review we aimed to describe the neurological phenotype of adults with early-treated phenylketonuria (ETPKU). The literature search covered the period from 1 January 1990 up to 16 April 2018, using the NLM MEDLINE controlled vocabulary. Of the 643 records initially identified, 83 were included in the analysis. The most commonly reported neurological signs were tremor and hyperreflexia. The overall quality of life (QoL) of ETPKU adults was good or comparable to control populations, and there was no evidence for a significant incidence of psychiatric disease or social difficulties. Neuroimaging revealed that brain abnormalities are present in ETPKU adults, but their clinical significance remains unclear. Generally, intelligence quotient (IQ) appears normal but specific deficits in neuropsychological and social functioning were reported in early-treated adults compared with healthy individuals. However, accurately defining the prevalence of these deficits is complicated by the lack of standardized neuropsychological tests. Future research should employ standardized neurological, neuropsychological, and neuroimaging protocols, and consider other techniques such as advanced imaging analyses and the recently validated PKU-specific QoL questionnaire, to precisely define the nature of the impairments within the adult ETPKU population and how these relate to metabolic control throughout life.
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Affiliation(s)
| | - Robin H Lachmann
- Charles Dent Metabolic Unit, National Hospital for Neurology and Neurosurgery, London, UK
| | - Renzo Manara
- Department of Medicine and Surgery, University of Salerno, Salerno, Italy
| | - Chiara Cazzorla
- Division of Inborn Metabolic Diseases, Department of Paediatrics, University Hospital, Padua, Italy
| | - Andrea Celato
- Division of Inborn Metabolic Diseases, Department of Paediatrics, University Hospital, Padua, Italy
| | - Francjan J van Spronsen
- Division of Metabolic Diseases, Beatrix Children's Hospital, University Medical Center of Groningen, University of Groningen, Groningen, The Netherlands
| | - Alberto Burlina
- Division of Inborn Metabolic Diseases, Department of Paediatrics, University Hospital, Padua, Italy
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9
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Bilder DA, Noel JK, Baker ER, Irish W, Chen Y, Merilainen MJ, Prasad S, Winslow BJ. Systematic Review and Meta-Analysis of Neuropsychiatric Symptoms and Executive Functioning in Adults With Phenylketonuria. Dev Neuropsychol 2016; 41:245-260. [PMID: 27805419 PMCID: PMC5152552 DOI: 10.1080/87565641.2016.1243109] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This systematic review and meta-analysis (MA) investigates the impact of elevated blood phenylalanine (Phe) on neuropsychiatric symptoms in adults with phenylketonuria (PKU). The meta-analysis of PKU is challenging because high-quality evidence is lacking due to the limited number of affected individuals and few placebo-controlled, double-blind studies of adults with high and low blood Phe. Neuropsychiatric symptoms associated with PKU exceed general population estimates for inattention, hyperactivity, depression, and anxiety. High Phe is associated with an increased prevalence of neuropsychiatric symptoms and executive functioning deficits whereas low Phe is associated with improved neurological performance. Findings support lifelong maintenance of low blood Phe.
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Affiliation(s)
- Deborah A Bilder
- a Department of Psychiatry , University of Utah , Salt Lake City , Utah
| | - J Kay Noel
- b CTI Clinical Trial and Consulting Services Inc ., Cincinnati , Ohio
| | - Erin R Baker
- b CTI Clinical Trial and Consulting Services Inc ., Cincinnati , Ohio
| | - William Irish
- b CTI Clinical Trial and Consulting Services Inc ., Cincinnati , Ohio
| | - Yinpu Chen
- c BioMarin Pharmaceutical Inc ., Novato , California
| | | | - Suyash Prasad
- d Audentes Therapeutics , San Francisco , California
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10
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Astrakas LG, Argyropoulou MI. Key concepts in MR spectroscopy and practical approaches to gaining biochemical information in children. Pediatr Radiol 2016; 46:941-51. [PMID: 27233787 DOI: 10.1007/s00247-014-3204-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 09/11/2014] [Accepted: 10/01/2014] [Indexed: 10/21/2022]
Abstract
Magnetic resonance spectroscopy (MRS) provides independent biochemical information and has become an invaluable adjunct to MRI and other imaging modalities. This review introduces key concepts and presents basic methodological steps regarding the acquisition and the interpretation of proton MRS. We review major brain metabolites and discuss MRS dependence on age, location, echo time and field strength.
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11
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Abstract
Proton magnetic resonance spectroscopy (1H MRS) is a noninvasive imaging technique that can easily be added to the conventional magnetic resonance (MR) imaging sequences. Using MRS one can directly compare spectra from pathologic or abnormal tissue and normal tissue. Metabolic changes arising from pathology that can be visualized by MRS may not be apparent from anatomy that can be visualized by conventional MR imaging. In addition, metabolic changes may precede anatomic changes. Thus, MRS is used for diagnostics, to observe disease progression, monitor therapeutic treatments, and to understand the pathogenesis of diseases. MRS may have an important impact on patient management. The purpose of this chapter is to provide practical guidance in the clinical application of MRS of the brain. This chapter provides an overview of MRS-detectable metabolites and their significance. In addition some specific current clinical applications of MRS will be discussed, including brain tumors, inborn errors of metabolism, leukodystrophies, ischemia, epilepsy, and neurodegenerative diseases. The chapter concludes with technical considerations and challenges of clinical MRS.
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Affiliation(s)
- Eva-Maria Ratai
- Division of Neuroradiology, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, and Athinoula A. Martinos Center for Biomedical Imaging, Boston, MA, USA.
| | - R Gilberto González
- Division of Neuroradiology, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, and Athinoula A. Martinos Center for Biomedical Imaging, Boston, MA, USA
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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.
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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
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Hood A, Antenor-Dorsey JAV, Rutlin J, Hershey T, Shimony JS, McKinstry RC, Grange DK, Christ SE, Steiner R, White DA. Prolonged exposure to high and variable phenylalanine levels over the lifetime predicts brain white matter integrity in children with phenylketonuria. Mol Genet Metab 2015; 114:19-24. [PMID: 25481106 PMCID: PMC4277899 DOI: 10.1016/j.ymgme.2014.11.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 11/04/2014] [Accepted: 11/06/2014] [Indexed: 10/24/2022]
Abstract
In this study, we retrospectively examined the microstructural white matter integrity of children with early- and continuously-treated PKU (N=36) in relation to multiple indices of phenylalanine (Phe) control over the lifetime. White matter integrity was assessed using mean diffusivity (MD) from diffusion tensor imaging (DTI). Eight lifetime indices of Phe control were computed to reflect average Phe (mean, index of dietary control), variability in Phe (standard deviation, standard error of estimate, % spikes), change in Phe with age (slope), and prolonged exposure to Phe (mean exposure, standard deviation exposure). Of these indices, mean Phe, mean exposure, and standard deviation exposure were the most powerful predictors of widespread microstructural white matter integrity compromise. Findings from the two previously unexamined exposure indices reflected the accumulative effects of elevations and variability in Phe. Given that prolonged exposure to elevated and variable Phe was particularly detrimental to white matter integrity, Phe should be carefully monitored and controlled throughout childhood, without liberalization of Phe control as children with PKU age.
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Affiliation(s)
- Anna Hood
- Department of Psychology, Washington University, Campus Box 1125, St. Louis, MO 63130, USA
| | - Jo Ann V Antenor-Dorsey
- Department of Psychiatry, Washington University School of Medicine, Campus Box 8134, St. Louis, MO 63110, USA
| | - Jerrel Rutlin
- Department of Psychiatry, Washington University School of Medicine, Campus Box 8134, St. Louis, MO 63110, USA
| | - Tamara Hershey
- Department of Psychiatry, Washington University School of Medicine, Campus Box 8134, St. Louis, MO 63110, USA; Mallinckrodt Institute of Radiology, Washington University School of Medicine, Campus Box 8131, St. Louis, MO 63110, USA; Department of Neurology, Washington University School of Medicine, Campus Box 8111, St. Louis, MO 63110, USA
| | - Joshua S Shimony
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, Campus Box 8131, St. Louis, MO 63110, USA
| | - Robert C McKinstry
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, Campus Box 8131, St. Louis, MO 63110, USA; Department of Pediatrics, Washington University School of Medicine, Campus Box 8116, St. Louis, MO 63110, USA
| | - Dorothy K Grange
- Department of Pediatrics, Washington University School of Medicine, Campus Box 8116, St. Louis, MO 63110, USA
| | - Shawn E Christ
- Department of Psychological Sciences, University of Missouri, 210 McAlester Hall, Columbia, MO 65211, USA
| | - Robert Steiner
- Department of Pediatrics, Institute on Development and Disability, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd., Portland, OR, 97239 USA; Department of Molecular & Medical Genetics, Institute on Development and Disability, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd., Portland, OR 97239, USA
| | - Desiree A White
- Department of Psychology, Washington University, Campus Box 1125, St. Louis, MO 63130, USA.
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Stevenson M, McNaughton N. A comparison of phenylketonuria with attention deficit hyperactivity disorder: do markedly different aetiologies deliver common phenotypes? Brain Res Bull 2013; 99:63-83. [PMID: 24140048 DOI: 10.1016/j.brainresbull.2013.10.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 09/04/2013] [Accepted: 10/07/2013] [Indexed: 01/21/2023]
Abstract
Phenylketonuria (PKU) is a well-defined metabolic disorder arising from a mutation that disrupts phenylalanine metabolism and so produces a variety of neural changes indirectly. Severe cognitive impairment can be prevented by dietary treatment; however, residual symptoms may be reported. These residual symptoms appear to overlap a more prevalent childhood disorder: Attention Deficit/Hyperactivity Disorder (ADHD). However, the aetiology of ADHD is a vast contrast to PKU: it seems to arise from a complex combination of genes; and it has a substantial environmental component. We ask whether these two disorders result from two vastly different genotypes that converge on a specific core phenotype that includes similar dysfunctions of Gray's (Gray, 1982) Behavioural Inhibition System (BIS), coupled with other disorder-specific dysfunctions. If so, we believe comparison of the commonalities will allow greater understanding of the neuropsychology of both disorders. We review in detail the aetiology, treatment, neural pathology, cognitive deficits and electrophysiological abnormalities of PKU; and compare this with selected directly matching aspects of ADHD. The biochemical and neural pathologies of PKU and ADHD are quite distinct in their causes and detail; but they result in the disorder in the brain of large amino acid levels, dopamine and white matter that are very similar and could explain the overlap of symptoms within and between the PKU and ADHD spectra. The common deficits affect visual function, motor function, attention, working memory, planning, and inhibition. For each of PKU and ADHD separately, a subset of deficits has been attributed to a primary dysfunction of behavioural inhibition. In the case of ADHD (excluding the inattentive subtype) this has been proposed to involve a specific failure of the BIS; and we suggest that this is also true of PKU. This accounts for a substantial proportion of the parallels in the superficial symptoms of both disorders and we see this as linked to prefrontal, rather than more general, dysfunction of the BIS.
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Enns GM, Koch R, Brumm V, Blakely E, Suter R, Jurecki E. Suboptimal outcomes in patients with PKU treated early with diet alone: revisiting the evidence. Mol Genet Metab 2010; 101:99-109. [PMID: 20678948 DOI: 10.1016/j.ymgme.2010.05.017] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2010] [Revised: 05/27/2010] [Accepted: 05/28/2010] [Indexed: 11/22/2022]
Abstract
BACKGROUND The National Institute of Health (NIH) published a Consensus Statement on the screening and management of Phenylketonuria (PKU) in 2000. The panel involved in the development of this consensus statement acknowledged the lack of data regarding the potential for more subtle suboptimal outcomes and the need for further research into treatment options. In subsequent years, the approval of new treatment options for PKU and outcome data for patients treated from the newborn period by dietary therapy alone have become available. We hypothesized that a review of the PKU literature since 2000 would provide further evidence related to neurocognitive, psychosocial, and physical outcomes that could serve as a basis for reassessment of the 2000 NIH Consensus Statement. METHODS A systematic review of literature residing in PubMed, Scopus and PsychInfo was performed in order to assess the outcome data over the last decade in diet-alone early-treated PKU patients to assess the need for new recommendations and validity of older recommendations in light of new evidence. RESULTS The majority of publications (140/150) that contained primary outcome data presented at least one suboptimal outcome compared to control groups or standardized norms/reference values in at least one of the following areas: neurocognitive/psychosocial (N=60; 58 reporting suboptimal outcomes); quality of life (N=6; 4 reporting suboptimal outcomes); brain pathology (N=32; 30 reporting suboptimal outcomes); growth/nutrition (N=34; 29 reporting suboptimal outcomes); bone pathology (N=9; 9 reporting suboptimal outcomes); and/or maternal PKU (N=19; 19 reporting suboptimal outcomes). CONCLUSIONS Despite the remarkable success of public health programs that have instituted newborn screening and early introduction of dietary therapy for PKU, there is a growing body of evidence that suggests that neurocognitive, psychosocial, quality of life, growth, nutrition, bone pathology and maternal PKU outcomes are suboptimal. The time may be right for revisiting the 2000 NIH Consensus Statement in order to address a number of important issues related to PKU management, including treatment advancements for metabolic control in PKU, blood Phe variability, neurocognitive and psychological assessments, routine screening measures for nutritional biomarkers, and bone pathology.
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Affiliation(s)
- G M Enns
- Division of Medical Genetics, Department of Pediatrics, Lucile Packard Children's Hospital, Stanford University, Stanford, CA 94305-5208,USA.
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Ghiasvand NM, Aledavood A, Ghiasvand R, Seyedin Borojeny F, Aledavood AR, Seyed S, Miner W, Saeb Taheri GR. Prevalence of classical phenylketonuria in mentally retarded individuals in Iran. J Inherit Metab Dis 2009; 32 Suppl 1:S283-7. [PMID: 19768570 DOI: 10.1007/s10545-009-1222-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2009] [Revised: 07/21/2009] [Accepted: 07/23/2009] [Indexed: 01/05/2023]
Abstract
Using Guthrie Biological Inhibition Assay, 4963 mentally retarded individuals housed in 31 cities and towns across the country were screened for PKU. The average prevalence of classical PKU in the study population was 2.1%, which is higher than that reported for most mentally retarded populations in other countries prior to the implementation of a nationwide newborn screening programme for PKU. The prevalence of PKU in 1814 mentally retarded inmates housed in shelters in Tehran was 2.81%, and the prevalence of the disease in 3149 inmates sheltered in other cities and towns was 1.68%. It appears that most of the difference between the prevalence of PKU in these two populations is due to a unique PKU referral pattern in Iran. The high prevalence of PKU in the mentally retarded population in Iran could be indicative of a high incidence of the disease among Iranian neonates. This in turn appears to be positively influenced by both a high frequency of the PKU allele and a high rate of consanguinity in the country. Our finding suggests that instead of limited local screening programmes in the country, a nationwide screening programme for PKU, especially if coupled with screening for congenital hypothyroidism, would be highly cost-effective and warranted.
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Affiliation(s)
- N M Ghiasvand
- Department of Biology, Grand Valley State University, Allendale, MI 49401, USA.
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Scarabino T, Popolizio T, Tosetti M, Montanaro D, Giannatempo GM, Terlizzi R, Pollice S, Maiorana A, Maggialetti N, Carriero A, Leuzzi V, Salvolini U. Phenylketonuria: white-matter changes assessed by 3.0-T magnetic resonance (MR) imaging, MR spectroscopy and MR diffusion. Radiol Med 2009; 114:461-74. [PMID: 19277839 DOI: 10.1007/s11547-009-0365-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Accepted: 10/06/2008] [Indexed: 12/13/2022]
Abstract
PURPOSE This study evaluated the sensitivity of a 3.0-Tesla (T) magnetic resonance imaging (MRI) in measuring cerebral phenylalanine using proton magnetic resonance spectroscopy and in assessing MR-documented white-matter changes by means of diffusion studies (diffusion-weighted imaging, apparent diffusion coefficient map; diffusion tensor imaging) in patients with phenylketonuria. MATERIALS AND METHODS Thirty-two patients with the classical clinical and biochemical deficits of phenylketonuria underwent biochemical (blood phenylalanine), genotypic (phenylalanine hydroxylase gene) and radiological investigation by means of MRI, proton magnetic resonance spectroscopy and diffusion magnetic resonance imaging with a 3.0-T scanner. RESULTS Periventricular and subcortical white-matter changes were detected on all MR scans. In 29/32 patients, proton magnetic resonance spectroscopy easily documented abnormal signal elevation at 7.36 ppm, corresponding to phenylalanine, despite its low concentration. Phenylalanine signal amplitude relative to the creatine/phosphocreatine signal increased linearly with blood phenylalanine values (r 0.7067; p<0.001). Diffusion MRI demonstrated hyperintensity in the areas exhibiting MRI changes as well as decreased apparent diffusion coefficient values, but fractional anisotropy indices were normal. CONCLUSIONS The high signal, together with better spectral, spatial, contrast and temporal resolution, makes the 3.0-T MR the most suitable technique in the study of the phenylketonuria. In particular, the multimodal approach with MRI, proton magnetic resonance spectroscopy and diffusion magnetic resonance imaging can provide more information than previous studies performed with low-field systems.
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Affiliation(s)
- T Scarabino
- U. O. di Neuroradiologia, AUSL BAT, Ospedale Lorenzo Bonomo, Andria, Italy.
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Anderson PJ, Wood SJ, Francis DE, Coleman L, Anderson V, Boneh A. Are Neuropsychological Impairments in Children with Early-Treated Phenylketonuria (PKU) Related to White Matter Abnormalities or Elevated Phenylalanine Levels? Dev Neuropsychol 2007; 32:645-68. [PMID: 17931123 DOI: 10.1080/87565640701375963] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Moyle JJ, Fox AM, Arthur M, Bynevelt M, Burnett JR. Meta-Analysis of Neuropsychological Symptoms of Adolescents and Adults with PKU. Neuropsychol Rev 2007; 17:91-101. [PMID: 17410469 DOI: 10.1007/s11065-007-9021-2] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2006] [Accepted: 12/08/2006] [Indexed: 10/23/2022]
Abstract
Phenylketonuria (PKU; OMIM 261600) is an autosomal recessive inborn error of phenylanaline metabolism. PKU is characterized by deficient or defective phenylalanine hydroxylase activity and persistantly increased levels of the essential amino acid phenylalanine in the circulation. The present article examines current understanding of the etiology of PKU, along with a meta-analysis examining neuropsychological and intellectual presentations in continuously treated adolescents and adults. Patients with PKU differed significantly from controls on Full-Scale IQ, processing speed, attention, inhibition, and motor control. Future research utilizing an integrative approach and detailed analysis of specific cognitive domains will assist both the scientist and clinician, and ultimately the patient.
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Affiliation(s)
- J J Moyle
- School of Psychology, The University of Western Australia, Perth, Australia.
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Leuzzi V, Tosetti M, Montanaro D, Carducci C, Artiola C, Carducci C, Antonozzi I, Burroni M, Carnevale F, Chiarotti F, Popolizio T, Giannatempo GM, D'Alesio V, Scarabino T. The pathogenesis of the white matter abnormalities in phenylketonuria. A multimodal 3.0 tesla MRI and magnetic resonance spectroscopy (1H MRS) study. J Inherit Metab Dis 2007; 30:209-16. [PMID: 17245558 DOI: 10.1007/s10545-006-0399-4] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2006] [Revised: 09/27/2006] [Accepted: 12/11/2006] [Indexed: 12/14/2022]
Abstract
OBJECTIVE To gain insights into the nature and pathogenesis of white matter (WM) abnormalities in PKU. METHODS Thirty-two patients with phenylalanine hydroxylase deficiency (21 with early and 11 with late diagnosis and treatment) and 30 healthy controls underwent an integrated clinical, neuroimaging (3.0 T MRI, diffusion-weighted imaging (DWI), diffusion tensor imaging (DTI)) and neurochemical (1H MRS) investigation. RESULTS All patients had white matter abnormalities on T2-weighted (T2W) and fluid-attenuated inversion recovery (FLAIR) scans; parietal white was consistently affected, followed by occipital, frontal and temporal white matter. T1-weighted hypointense alterations were also found in 8 of 32 patients. DWI hyperintense areas overlapped with those detected on T2W/FLAIR. The apparent diffusion coefficient (ADC) was reduced and correlated inversely with severity of white matter involvement. Fractional anisotropy index, eigenvalues lambda(min), lambda(middle), lambda(max) obtained from DTI data, and the principal brain metabolites assessed by 1H MRS (except brain phenylalanine (Phe)) were normal. Brain Phe peak was detected in all but two subjects. Brain and blood Phe were strictly associated. Blood Phe at the diagnosis, patient's age, and concurrent brain Phe independently influence white matter alteration (as expressed by conventional MRI or ADC values). CONCLUSIONS (a) MRI abnormalities in phenylketonuria are the result of a distinctive alteration of white matter suggesting the intracellular accumulation of a hydrophilic metabolite, which leaves unaffected white matter architecture and structure. (b) White matter abnormalities do not seem to reflect the mechanisms involved in the derangement of mental development in PKU. (c) Our data do not support the usefulness of conventional brain MRI examination in the clinical monitoring of phenylketonuria patients.
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Affiliation(s)
- V Leuzzi
- Dipartimento di Scienze Neurologiche e Psichiatriche dell'Età Evolutiva, University of Rome La Sapienza, Rome, Italy.
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Vermathen P, Robert-Tissot L, Pietz J, Lutz T, Boesch C, Kreis R. Characterization of white matter alterations in phenylketonuria by magnetic resonance relaxometry and diffusion tensor imaging. Magn Reson Med 2007; 58:1145-56. [PMID: 18046700 DOI: 10.1002/mrm.21422] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Peter Vermathen
- Department Clinical Research, Unit for MR-Spectroscopy & Methodology, University Berne, Bern, Switzerland
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Abstract
The neurologic manifestations of patients with phenylketonuria treated at different ages are illustrated in this series of 146 cases, including 9 sib pairs. In addition to well-known findings such as mental retardation, autistic features, microcephaly, and tremor, motor retardation was common and responded promptly to dietary treatment. Hypotonia and diminished reflexes were more frequent findings than hypertonia. Four sib pairs showed divergent features, such as the later-treated sibling having higher function than the early-treated one. Because siblings have a similar genotype and similar environmental and dietary conditions, this observation can be explained by differences in phenylalanine transport to the brain or additional metabolic or perinatal factors influencing the neurologic outcome.
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Abstract
AIMS To determine the prevalence, the types and severity of hyperphenylalaninaemia (including phenylketonuria (PKU)) in Victoria and to report on a new treatment modality of PKU. METHODS We reviewed the medical records of all patients diagnosed with high blood phenylalanine levels by newborn screening between November 2001 and October 2004. RESULTS We identified 17 newborn babies with high levels of blood phenylalanine (total samples: 190,835). Dihydrobiopterin reductase deficiency was excluded in all babies. Five babies had persistent phenylalanine levels of 200-300, and do not receive any dietary or pharmaceutical therapy. One baby was diagnosed as having pyruvoyl tetrahydro-pterin synthase deficiency. Following reports of tetrahydrobiopterin (BH(4))-responsive PKU, we have performed a BH(4) load (20 mg/kg, 6R-5,6,7,8-tetrahydro-L-biopetrin dehydrochloride; Schricks Laboratories, Jona, Switzerland) in 10 newborn babies with PKU (one baby with a phenylalanine level of 2600 micromol/L was started on diet without prior load). Three babies had a significant response to BH(4) (>35% decrease in phenylalanine level). Protein restriction (1.2 g/kg/day) and introduction of phenylalanine-free formula, in addition to BH(4) treatment, were necessary in one patient. The other patients maintain good metabolic control with BH(4) treatment only (at approximately 11 mg/kg/day) and an intake of 2-3 g protein per day. Of the nine babies who are on a full PKU diet, three have high phenylalanine tolerance (consistently >40 mg/kg/day). CONCLUSION There is a spectrum of severity of hyperphenylalaninaemia in the population. The detection of BH(4)-responsive PKU patients offers them a less restrictive dietary regimen and an improved quality of life, and may enable near normal life-style in adolescence.
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Affiliation(s)
- Avihu Boneh
- Metabolic Service, Genetic Health Services Victoria, Royal Children's Hospital, Parkville, Vic., Australia.
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Abstract
The application of MR spectroscopy (MRS) in pediatric brain disorders yields valued information on pathologic processes, such as ischemia, demyelination, gliosis, and neurodegeneration. Because these processes manifest in inborn errors of metabolism, the purposes of this article are to (1) describe the spectral changes that are associated with the relatively common metabolic disorders, with summaries of known spectroscopic features of these disorders; (2) offer suggestions for recognition and distinction of disorders; and (3) provide general guidelines for MRS implementation. Although many conditions have a similar presentation, MRS offers valuable information for the individual patient in diagnosis and therapy when integrated fully into the clinical setting.
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Affiliation(s)
- Kim M Cecil
- Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA.
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25
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Abstract
The test-retest reliability of two-dimensional (2D) correlated spectroscopy (COSY) was studied on a whole-body 1.5T MRI scanner. Single-voxel localized 2D proton spectra were recorded in vitro as well as in vivo using a recently implemented localized chemical shift correlated spectroscopic (L-COSY) sequence. A total of 40 in vitro and 40 human brain (10 volunteers, four times each) 2D L-COSY spectra were recorded. The coefficients of variation (CVs) of selected brain metabolites (raw volume integrals) recorded in 10 healthy volunteers were less than 9% for creatine, choline, and N-acetyl aspartate, and less than 17% for myo-inositol, glutamine/glutamate, aspartate, and threonine/lactate. The 2D metabolite ratios and the raw volume integrals of 2D diagonal and cross peaks in healthy human brain were very well reproduced. The intraclass correlation coefficients were greater than 0.4 (P < 0.05) for the major metabolites, indicating that the 2D peak volumes were stable enough within individuals to detect reliable differences between normal subjects.
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Affiliation(s)
- Nader Binesh
- Department of Radiological Sciences, UCLA School of Medicine, University of California-Los Angeles, Los Angeles, California 90095-1721, USA
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Wennerberg AB, Jonsson T, Forssberg H, Li TQ. Current awareness in NMR in biomedicine. NMR Biomed 2001; 14:48-53. [PMID: 11252040 DOI: 10.1002/nbm.667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In order to keep subscribers up-to-date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of NMR in biomedicine. Each bibliography is divided into 9 sections: 1 Books, Reviews ' Symposia; 2 General; 3 Technology; 4 Brain and Nerves; 5 Neuropathology; 6 Cancer; 7 Cardiac, Vascular and Respiratory Systems; 8 Liver, Kidney and Other Organs; 9 Muscle and Orthopaedic. Within each section, articles are listed in alphabetical order with respect to author. If, in the preceding period, no publications are located relevant to any one of these headings, that section will be omitted.
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Affiliation(s)
- A B Wennerberg
- Department of KARO, Division of Diagnostic Radiology, Karolinska Institutet, Huddinge University Hospital, SE-141 86 Stockholm, Sweden
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