1
|
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
|
2
|
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] [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.
Collapse
|
3
|
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 mental handicap; 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. 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 STRATEGY 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: 05 March 2009. 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.
Collapse
Affiliation(s)
- Vanessa J Poustie
- Alder Hey Children's NHS Foundation TrustInstitute of Child Health, University of LiverpoolEaton RoadLiverpoolMerseysideUKL12 2AP
| | - Joanne Wildgoose
- Bradford Royal InfirmaryPhysio Corridor, Level 1Duckworth LaneBradfordUKBD9 6RJ
| | | |
Collapse
|
4
|
Russell VA, Oades RD, Tannock R, Killeen PR, Auerbach JG, Johansen EB, Sagvolden T. Response variability in Attention-Deficit/Hyperactivity Disorder: a neuronal and glial energetics hypothesis. Behav Brain Funct 2006; 2:30. [PMID: 16925830 PMCID: PMC1624838 DOI: 10.1186/1744-9081-2-30] [Citation(s) in RCA: 167] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2006] [Accepted: 08/23/2006] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Current concepts of Attention-Deficit/Hyperactivity Disorder (ADHD) emphasize the role of higher-order cognitive functions and reinforcement processes attributed to structural and biochemical anomalies in cortical and limbic neural networks innervated by the monoamines, dopamine, noradrenaline and serotonin. However, these explanations do not account for the ubiquitous findings in ADHD of intra-individual performance variability, particularly on tasks that require continual responses to rapid, externally-paced stimuli. Nor do they consider attention as a temporal process dependent upon a continuous energy supply for efficient and consistent function. A consideration of this feature of intra-individual response variability, which is not unique to ADHD but is also found in other disorders, leads to a new perspective on the causes and potential remedies of specific aspects of ADHD. THE HYPOTHESIS We propose that in ADHD, astrocyte function is insufficient, particularly in terms of its formation and supply of lactate. This insufficiency has implications both for performance and development: H1) In rapidly firing neurons there is deficient ATP production, slow restoration of ionic gradients across neuronal membranes and delayed neuronal firing; H2) In oligodendrocytes insufficient lactate supply impairs fatty acid synthesis and myelination of axons during development. These effects occur over vastly different time scales: those due to deficient ATP (H1) occur over milliseconds, whereas those due to deficient myelination (H2) occur over months and years. Collectively the neural outcomes of impaired astrocytic release of lactate manifest behaviourally as inefficient and inconsistent performance (variable response times across the lifespan, especially during activities that require sustained speeded responses and complex information processing). TESTING THE HYPOTHESIS Multi-level and multi-method approaches are required. These include: 1) Use of dynamic strategies to evaluate cognitive performance under conditions that vary in duration, complexity, speed, and reinforcement; 2) Use of sensitive neuroimaging techniques such as diffusion tensor imaging, magnetic resonance spectroscopy, electroencephalography or magnetoencephalopathy to quantify developmental changes in myelination in ADHD as a potential basis for the delayed maturation of brain function and coordination, and 3) Investigation of the prevalence of genetic markers for factors that regulate energy metabolism (lactate, glutamate, glucose transporters, glycogen synthase, glycogen phosphorylase, glycolytic enzymes), release of glutamate from synaptic terminals and glutamate-stimulated lactate production (SNAP25, glutamate receptors, adenosine receptors, neurexins, intracellular Ca2+), as well as astrocyte function (alpha1, alpha2 and beta-adrenoceptors, dopamine D1 receptors) and myelin synthesis (lactate transporter, Lingo-1, Quaking homolog, leukemia inhibitory factor, and Transferrin). IMPLICATIONS OF THE HYPOTHESIS The hypothesis extends existing theories of ADHD by proposing a physiological basis for specific aspects of the ADHD phenotype - namely frequent, transient and impairing fluctuations in functioning, particularly during performance of speeded, effortful tasks. The immediate effects of deficient ATP production and slow restoration of ionic gradients across membranes of rapidly firing neurons have implications for daily functioning: For individuals with ADHD, performance efficacy would be enhanced if repetitive and lengthy effortful tasks were segmented to reduce concurrent demands for speed and accuracy of response (introduction of breaks into lengthy/effortful activities such as examinations, motorway driving, assembly-line production). Also, variations in task or modality and the use of self- rather than system-paced schedules would be helpful. This would enable energetic demands to be distributed to alternate neural resources, and energy reserves to be re-established. Longer-term effects may manifest as reduction in regional brain volumes since brain areas with the highest energy demand will be most affected by a restricted energy supply and may be reduced in size. Novel forms of therapeutic agent and delivery system could be based on factors that regulate energy production and myelin synthesis. Since the phenomena and our proposed basis for it are not unique to ADHD but also manifests in other disorders, the implications of our hypotheses may be relevant to understanding and remediating these other conditions as well.
Collapse
Affiliation(s)
- Vivienne A Russell
- Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Anzio Road, Observatory 7925, South Africa
| | - Robert D Oades
- University Clinic for Child and Adolescent Psychiatry, Virchowstr. 174, 45147 Essen, Germany
| | - Rosemary Tannock
- Research Institute of The Hospital for Sick Children, University of Toronto, Canada
| | - Peter R Killeen
- Department of Psychology, Arizona State University, Tempe, AZ 85287-1104, USA
| | - Judith G Auerbach
- Department of Behavioural Sciences, Ben-Gurion University, Beer Sheva, 84105, Israel
| | - Espen B Johansen
- Department of Physiology, University of Oslo, N-0317 Oslo, Norway
| | - Terje Sagvolden
- Department of Physiology, University of Oslo, N-0317 Oslo, Norway
| |
Collapse
|
5
|
Martynyuk AE, Glushakov AV, Sumners C, Laipis PJ, Dennis DM, Seubert CN. Impaired glutamatergic synaptic transmission in the PKU brain. Mol Genet Metab 2005; 86 Suppl 1:S34-42. [PMID: 16153867 DOI: 10.1016/j.ymgme.2005.06.014] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2005] [Revised: 06/23/2005] [Accepted: 06/24/2005] [Indexed: 11/24/2022]
Abstract
This paper reviews recent results of our investigation of the mechanisms whereby hyperphenylalaninemia may cause brain dysfunction in classical phenylketonuria (PKU). Acute applications of L-Phe in rat and mouse hippocampal and cerebrocortical cultured neurons, at a range of concentrations found in PKU brain, significantly and reversibly depressed glutamatergic synaptic transmission by a combination of pre- and postsynaptic actions: (1) competition for the glycine-binding site of the N-methyl-D-aspartate (NMDA) receptors; (2) attenuation of neurotransmitter release; (3) competition for the glutamate-binding site of (RS)-amino-3-hydroxy-5-methyl-4-isoxazolepropioinic acid and kainate (AMPA/kainate) receptors. Unlike L-Phe, its non-tyrosine metabolites, phenylacetic acid, phenylpyruvic acid, and phenyllactic acid, did not produce antiglutamatergic effects. L-Phe did not affect inhibitory gamma-aminobutyric (GABA)-ergic transmission. Consistent with this specific pattern of effects caused by L-Phe in neuronal cultures, the expression of NMDA receptor NR2A and AMPA receptor Glu1 and Glu2/3 subunits in brain of hyperphenylalaninemic PKU mice (Pah(enu2) strain) was significantly increased, whereas expression of the NMDA receptor NR2B subunit was decreased. There was no change in GABA alpha1 subunit expression. Considering the important role of glutamatergic synaptic transmission in normal brain development and function, these L-Phe-induced changes in glutamatergic synaptic transmission in PKU brain may be a critical element of the neurological symptoms of PKU.
Collapse
Affiliation(s)
- A E Martynyuk
- Department of Anesthesiology, University of Florida, Gainesville, FL, USA.
| | | | | | | | | | | |
Collapse
|
6
|
Pietz J, Rupp A, Ebinger F, Rating D, Mayatepek E, Boesch C, Kreis R. Cerebral energy metabolism in phenylketonuria: findings by quantitative In vivo 31P MR spectroscopy. Pediatr Res 2003; 53:654-62. [PMID: 12612190 DOI: 10.1203/01.pdr.0000055867.83310.9e] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Both severe impairments of brain development in untreated infants and acute reversible neurotoxic effects on brain function are clinical features of phenylketonuria (PKU). For determining whether impairments of cerebral energy metabolism play a role in the pathophysiology of PKU, quantitative in vivo 31P magnetic resonance spectroscopy (MRS) was performed in a supratentorial voxel of 11 adult PKU patients and controls. Peak areas of inorganic phosphate; phosphocreatine; alpha-, beta-, and gamma-ATP; NAD; phosphomonoesters; phosphodiesters; and a broad phospholipid signal were converted to millimolar concentrations. Mg2+, pH, ADP, the phosphorylation potential, and the relative velocity of oxidative metabolism V/Vmax were derived. Clinical evaluation included mutation analysis, neurologic investigation, intelligence testing, magnetic resonance imaging, and concurrent plasma and brain phenylalanine (Phe), the last by 1H-MRS. Phe loading was performed in five patients with an oral dose of 100 mg/kg body wt L-Phe monitored by spectral EEG analysis. Under steady-state conditions, 31P-MRS revealed normal values for ATP, phosphocreatine, NAD, phosphomonoesters, phosphodiesters, Mg2+, and pH in PKU. ADP (+11%) and the phosphorylation potential (+22%) were increased. Peak areas of inorganic phosphate (-22%) and phospholipid (-8%) were decreased. ADP correlated with concurrent plasma (r = 0.65) and brain (r = 0.55) Phe. During the Phe load, blood Phe levels increased steeply. EEG revealed slowing of background activity. The phosphorylation potential decreased, whereas ADP and V/Vmax increased. In vivo 31P-MRS demonstrated subtle abnormalities of cerebral energy metabolism in PKU in steady-state conditions that were accentuated by a Phe load, indicating a link between Phe neurotoxicity and imbalances of cerebral energy metabolism.
Collapse
Affiliation(s)
- Joachim Pietz
- Department of Pediatric Neurology, Division of Metabolic and Endocrine Diseases, University of Heidelberg, Im Neuenheimer Feld 150, Germany.
| | | | | | | | | | | | | |
Collapse
|
7
|
Salinsky MC, Binder LM, Oken BS, Storzbach D, Aron CR, Dodrill CB. Effects of gabapentin and carbamazepine on the EEG and cognition in healthy volunteers. Epilepsia 2002; 43:482-90. [PMID: 12027908 DOI: 10.1046/j.1528-1157.2002.22501.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE Antiepileptic drug (AED) therapy can be associated with neurotoxic side effects including cognitive dysfunction. Objective methods for detection of neurotoxicity in individual patients would be useful. We studied the effects of gabapentin (GBP) and carbamazepine (CBZ) on neurophysiologic and cognitive/behavioral measures in healthy volunteers. METHODS In a 12-week, randomized, double-blind, parallel-group study of CBZ and GBP in healthy volunteers, 23 subjects completed the protocol. All achieved the target dose of 1,200 mg CBZ or 3,600 mg GBP. A structured EEG for quantitative analysis and a cognitive test battery were administered before AED therapy and again after 12 weeks of therapy. Test-retest differences were compared with those of 72 untreated control subjects. RESULTS Both CBZ and GBP significantly decreased the peak frequency of the posterior (alpha) rhythm, with CBZ exerting a greater effect. Ten CBZ and six GBP subjects exceeded the 95% confidence interval (CI) for an individual. Cognitive tests revealed AED vs. control group effects for two of seven measures (Digit Symbol, Stroop) and all subjective measures. However, few subjects exceeded the 95% CI for any objective test. Differences between CBZ and GBP were not significant. Greater EEG slowing was associated with greater subjective neurotoxicity and poorer test-retest performance on a cognitive test summary measure. CONCLUSIONS Prolonged CBZ and GBP therapy induced EEG slowing that correlated with cognitive complaints and often exceeded the confidence interval for individual subjects. Quantitative EEG measures may be useful in the objective determination of AED-related neurotoxicity.
Collapse
Affiliation(s)
- Martin C Salinsky
- Oregon Health Sciences University Epilepsy Center, Portland, Oregon 97201, USA.
| | | | | | | | | | | |
Collapse
|
8
|
Butchko HH, Stargel WW, Comer CP, Mayhew DA, Benninger C, Blackburn GL, de Sonneville LMJ, Geha RS, Hertelendy Z, Koestner A, Leon AS, Liepa GU, McMartin KE, Mendenhall CL, Munro IC, Novotny EJ, Renwick AG, Schiffman SS, Schomer DL, Shaywitz BA, Spiers PA, Tephly TR, Thomas JA, Trefz FK. Aspartame: review of safety. Regul Toxicol Pharmacol 2002; 35:S1-93. [PMID: 12180494 DOI: 10.1006/rtph.2002.1542] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Over 20 years have elapsed since aspartame was approved by regulatory agencies as a sweetener and flavor enhancer. The safety of aspartame and its metabolic constituents was established through extensive toxicology studies in laboratory animals, using much greater doses than people could possibly consume. Its safety was further confirmed through studies in several human subpopulations, including healthy infants, children, adolescents, and adults; obese individuals; diabetics; lactating women; and individuals heterozygous (PKUH) for the genetic disease phenylketonuria (PKU) who have a decreased ability to metabolize the essential amino acid, phenylalanine. Several scientific issues continued to be raised after approval, largely as a concern for theoretical toxicity from its metabolic components--the amino acids, aspartate and phenylalanine, and methanol--even though dietary exposure to these components is much greater than from aspartame. Nonetheless, additional research, including evaluations of possible associations between aspartame and headaches, seizures, behavior, cognition, and mood as well as allergic-type reactions and use by potentially sensitive subpopulations, has continued after approval. These findings are reviewed here. The safety testing of aspartame has gone well beyond that required to evaluate the safety of a food additive. When all the research on aspartame, including evaluations in both the premarketing and postmarketing periods, is examined as a whole, it is clear that aspartame is safe, and there are no unresolved questions regarding its safety under conditions of intended use.
Collapse
Affiliation(s)
- Harriett H Butchko
- Medical and Scientific Affairs, The NutraSweet Company, Mt Prospect, Illinois 60056, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Blum K, Braverman ER, Holder JM, Lubar JF, Monastra VJ, Miller D, Lubar JO, Chen TJ, Comings DE. Reward deficiency syndrome: a biogenetic model for the diagnosis and treatment of impulsive, addictive, and compulsive behaviors. J Psychoactive Drugs 2000; 32 Suppl:i-iv, 1-112. [PMID: 11280926 DOI: 10.1080/02791072.2000.10736099] [Citation(s) in RCA: 542] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The dopaminergic system, and in particular the dopamine D2 receptor, has been implicated in reward mechanisms. The net effect of neurotransmitter interaction at the mesolimbic brain region induces "reward" when dopamine (DA) is released from the neuron at the nucleus accumbens and interacts with a dopamine D2 receptor. "The reward cascade" involves the release of serotonin, which in turn at the hypothalmus stimulates enkephalin, which in turn inhibits GABA at the substania nigra, which in turn fine tunes the amount of DA released at the nucleus accumbens or "reward site." It is well known that under normal conditions in the reward site DA works to maintain our normal drives. In fact, DA has become to be known as the "pleasure molecule" and/or the "antistress molecule." When DA is released into the synapse, it stimulates a number a DA receptors (D1-D5) which results in increased feelings of well-being and stress reduction. A consensus of the literature suggests that when there is a dysfunction in the brain reward cascade, which could be caused by certain genetic variants (polygenic), especially in the DA system causing a hypodopaminergic trait, the brain of that person requires a DA fix to feel good. This trait leads to multiple drug-seeking behavior. This is so because alcohol, cocaine, heroin, marijuana, nicotine, and glucose all cause activation and neuronal release of brain DA, which could heal the abnormal cravings. Certainly after ten years of study we could say with confidence that carriers of the DAD2 receptor A1 allele have compromised D2 receptors. Therefore lack of D2 receptors causes individuals to have a high risk for multiple addictive, impulsive and compulsive behavioral propensities, such as severe alcoholism, cocaine, heroin, marijuana and nicotine use, glucose bingeing, pathological gambling, sex addiction, ADHD, Tourette's Syndrome, autism, chronic violence, posttraumatic stress disorder, schizoid/avoidant cluster, conduct disorder and antisocial behavior. In order to explain the breakdown of the reward cascade due to both multiple genes and environmental stimuli (pleiotropism) and resultant aberrant behaviors, Blum united this hypodopaminergic trait under the rubric of a reward deficiency syndrome.
Collapse
Affiliation(s)
- K Blum
- Department of Biological Sciences, University of North Texas, Denton, Texas, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Singh RH, Kable JA, Guerrero NV, Sullivan KM, Elsas LJ. Impact of a camp experience on phenylalanine levels, knowledge, attitudes, and health beliefs relevant to nutrition management of phenylketonuria in adolescent girls. JOURNAL OF THE AMERICAN DIETETIC ASSOCIATION 2000; 100:797-803. [PMID: 10916518 DOI: 10.1016/s0002-8223(00)00232-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
OBJECTIVE To evaluate the effectiveness of an education intervention in a summer camp setting on knowledge, attitudes, and health beliefs regarding metabolic control of phenylketonuria and dietary compliance. DESIGN An observational study of a weeklong metabolic camp for adolescent girls with phenylketonuria (PKU) who were followed up over the course of 1 year. Observations also were made in 3 subsequent years of camp. INTERVENTION The camp experience consisted of diet and disease education, sessions on reproductive development, and recreation. Group discussions on attitudes and perceptions about PKU related to dietary compliance were held with nutritionists and a pediatric psychologist. OUTCOME MEASURES Biochemical and psychological data were collected on the first and last days of the camp to assess short-term effects of the intervention, then at quarterly intervals during the year to determine the long-term impact of the camp. Precamp and Postcamp plasma amino acid data for the subsequent 3 years were also collected. SUBJECTS/SETTING Analyses were based on 13 adolescent girls with PKU in the first year of a camp at Emory University in Atlanta, Ga, and compared with data from 11 additional campers enrolled the second year, 8 in the third year, and 7 in the fourth year. Mean age +/- standard deviation of first-year campers was 13 +/- 2 years, mean IQ +/- standard deviation was 98 +/- 16, and 9 of 13 girls had menstruated. STATISTICAL ANALYSES PERFORMED Short-term effects of the intervention were computed by comparing mean levels of response from the baseline period to those from the last day of camp using t tests for dependent samples. Repeated-measures analysis of variance was used to assess the long-term effects of the camp experience over the course of a year at regular quarterly intervals. RESULTS Short-term effects of the education intervention were significant reductions in dietary phenylalanine intake, plasma phenylalanine levels, and perceived isolation. However, these effects progressively returned to baseline levels over the course of a year. The significant short- and long-term effects of increased knowledge of diet and disease persisted throughout the study period. APPLICATIONS/CONCLUSIONS Short-term effects of the education intervention resulted in improved metabolic control associated with improved attitudes, increased knowledge of diet and disease, increased perceived support, and decreased barriers to dietary compliance in a camp setting.
Collapse
Affiliation(s)
- R H Singh
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | | | | | | | | |
Collapse
|
11
|
Abstract
BACKGROUND Phenylketonuria is an inherited disease for which the main treatment is the dietary restriction of the amino acid phenylalanine. The diet has to be initiated in the neonatal period to prevent or reduce mental handicap however the diet is very restrictive and unpalatable and can be difficult to follow. Whether the diet can be relaxed or discontinued during adolescence or should be continued for life remains a contraversial issue which we aim to address in this review. OBJECTIVES To assess the effects of a phenylalanine restricted diet commenced early in life for patients with phenylketonuria. To assess the possible adverse effects of relaxation or termination of the diet on intelligence, neuropsychological outcomes and mortality, and to assess the effect on growth, nutritional status and eating behaviour and quality of life. SEARCH STRATEGY We searched the Cochrane Cystic Fibrosis and Genetic Disorders Trials Register which is a specialist trials register which comprises references identified from comprehensive electronic database searches, handsearching relevant journals and handsearching abstract books of conference proceedings. Additional studies were identified from handsearching the Journal of Inherited Metabolic Disease (from inception, 1978 to 1998). The manufacturers of dietary products for phenylketonuria were also contacted. Date of the most recent search of the Group's specialised register: November 1999. SELECTION CRITERIA All randomised or pseudorandomised controlled trials comparing a phenylalanine restricted diet to either relaxation or termination of dietary restrictions in patients with phenylketonuria. DATA COLLECTION AND ANALYSIS Two reviewers independently assessed the trial eligibility, methodological quality and extracted the data. MAIN RESULTS Four studies were included in this review including a total of 251 patients. Few statistically significant differences were found between treatment and comparison groups for any of the outcomes apart from for blood phenylalanine level and intelligence quotient. Blood phenylalanine levels were significantly lower in those subjects with phenylketonuria following a phenylalanine restricted diet compared to those on a less restricted or relaxed diet (weighted mean difference at three months -672.203, 95% Confidence interval (CI) -813.799 to - 530.608). Intelligence quotient was significantly higher in subjects who continued on the phenylalanine restricted diet compared to those who terminated the diet (weighted mean difference after 12 months -5.00, 95% CI -9.595 to -0.405). However this is based on the results of only one study. REVIEWER'S CONCLUSIONS The results of non-randomised studies have concluded that a phenylalanine restricted diet is effective in reducing blood phenylalanine levels and improving intelligence quotient and neuropsychological outcome. No randomised controlled trials have assessed the effect of a phenylalanine restricted diet versus no dietary restrictions from diagnosis. In view of evidence from non-randomised studies, such a trial would now be unethical and it is recommended that phenylalanine restricted 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. These questions should be addressed by randomised controlled trials with careful consideration given to which patients to include.
Collapse
Affiliation(s)
- V J Poustie
- Evidence Based Child Health Unit, Institute of Child Health, Royal Liverpool Children's Hospital NHS Trust, Alder Hey, Eaton Road, Liverpool, Merseyside, UK, L12 2AP.
| | | |
Collapse
|
12
|
Abstract
Phenylketonuria, an autosomal recessively transmitted disorder of amino acid metabolism, is caused by a deficiency of hepatic phenylalanine hydroxylase converting phenylalanine to tyrosine. Thus, phenylalanine accumulates to plasma levels exceeding 1200 mumol/l. Untreated phenylketonuria is characterized by microcephaly, epilepsy, severe mental retardation and, in some cases, progressive supranuclear motor disturbances. These symptoms can largely be prevented by the early start of a phenylalanine-restricted diet. Neurological investigations of treated patients reveal only minor neurological signs, such as tremor or brisk deep tendon reflexes. Magnetic resonance imaging shows white matter abnormalities. However, in single patients, progressive neurological symptoms occurred. Thus, the long-term prognosis of treated phenylketonuria is still under discussion.
Collapse
Affiliation(s)
- J Pietz
- Department of Pediatric Neurology, University of Heidelberg, Germany.
| |
Collapse
|
13
|
Braverman ER, Blum K. Substance use disorder exacerbates brain electrophysiological abnormalities in a psychiatrically-ill population. CLINICAL EEG (ELECTROENCEPHALOGRAPHY) 1996; 27:5-27. [PMID: 8902324 DOI: 10.1177/1550059496027s0402] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To assess by brain electrical activity mapping whether cocaine and alcohol abuse and dependence would exacerbate electro-physiological abnormalities in a psychiatrically-ill population. DESIGN, SETTING, AND PARTICIPANTS Utilizing a brain mapping system, we assessed EEG, Spectral Analysis (Quantitative EEG[QEEG]). Evoked Potentials (Auditory and Visual), and P300 (cognitive evoked potential), in a total of 111 probands divided into three groups: controls (N = 16), psychiatrically-ill without comorbid substance use disorder (N = 34), and psychiatrically-ill with comorbid substance use disorder (cocaine and alcohol abuse and dependence) (N = 61), at an outpatient neuropsychiatric clinic. With regard to demographic data, the group participating in this study did not differ significantly. A comparison was made among the groups to assist in differentiating the effects of substance use disorder compared to psychiatric disease on brain electrical activity. MAIN OUTCOME MEASURES An assessment of electrophysiological abnormalities and their brain location in psychiatric and substance use disorder patients was done with a brain electrical activity mapping test. MAIN RESULTS Among the non-substance use disorder, psychiatrically-ill (PI) and substance use disorder, psychiatrically-ill (PI/SD) groups, significantly different brain map abnormalities were observed relative to an assessed normal population MANOVA (P = .017). Moreover, with regard to Spectral Analysis, ANOVA was significant at a P = .038, and we found a weighted linear trend of increased abnormal total spectral analysis (P = .0113), whereby substance use was significantly worse than controls. Moreover among the PI and PI/SD groups, significantly greater total evoked potential (EP) brain trap abnormalities were observed when compared with a characterized normal population (P = .0023) with increasing abnormalities as a function of substance use disorder as measured by a weighted linear trend (P = .0022). In order to determine the site of the EPS abnormalities, we evaluated these abnormalities by location. In this regard, we found all temporal abnormalities (AVBITA, see Table 2) among the PI and PI/SD groups to be significantly greater relative to an assessed normal population (P = .0026). Furthermore, we observed a linear trend of increased temporal abnormalities with increasing substance use disorder (P < .0008). In terms of bitemporal abnormalities (AVBIT) among the PI and PI/SD groups, we also found significantly more bitemporal lobe abnormalities in the PI/SD group compared to our control population (P = .009). Additionally, a weighted linear trend of increased abnormal bitemporal lobe abnormalities was observed with increasing substance use disorder (P = .0022). In the frontal lobe similar findings were observed. With AVBIFA the ANOVA was P < .011, with a weighted linear trend of P < .005 and the PI/SD group were significantly more abnormal than PI or CS on a Duncan Range test. It is noteworthy that in a selected group of depressed (Major Depressive Disorder Recurrent, 296.3) patients, we found profound abnormalities in the various brain map parameters tested. MANOVA and Univariate ANOVA's revealed significantly greater abnormalities in the PI and PI/SD groups compared to assessed controls. A MANOVA for total brain abnormalities was significant at P = .043 and univariate ANOVA's for composite measurements of TSA (P = .017), EPS (P = .0002), AVBITA (P = .000015), and AVBIT (P < .00002) are also significant. With regard to EPS and AVBITA a weighted linear trend was observed where there were increasing abnormalities with increasing substance use disorder, P = .0001 and P = .000003, respectively. Most importantly we found that in addition to increased abnormalities with increasing substance use disorder the PI/SD group had significantly more abnormalities compared to the PI group with regard to both the TSA (P < .05) and AVBIT (P < .05) composite parameters as meas
Collapse
Affiliation(s)
- E R Braverman
- Department of Psychiatry, New York University School of Medicine, New York, New York, USA
| | | |
Collapse
|
14
|
Pietz J, Landwehr R, Kutscha A, Schmidt H, de Sonneville L, Trefz FK. Effect of high-dose tyrosine supplementation on brain function in adults with phenylketonuria. J Pediatr 1995; 127:936-43. [PMID: 8523192 DOI: 10.1016/s0022-3476(95)70031-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
OBJECTIVES To characterize abnormalities of brain function in patients with phenylketonuria (PKU) who had relaxed or stopped the dietary regimen and to test whether oral high-dose tyrosine (Tyr) supplementation has a beneficial effect. DESIGN Comparison with a control group; double-blind, placebo-controlled study comprising six test times; crossover treatment groups; oral high-dose Tyr therapy (100 mg/kg body weight per day) or placebo administration for 4 weeks. SUBJECTS Twenty-four early-treated patients with PKU aged 20.8 (16 to 25) years; 24 control subjects. METHODS Plasma concentrations of phenylalanine and Tyr were monitored. Neuropsychologic tasks, visual evoked potentials, and spectral analysis of electroencephalographic activity were used to evaluate brain function. RESULTS When patients with PKU were compared with control subjects, deficits in certain aspects of brain function were confirmed (i.e., a decreased ability to sustain attention, prolonged latencies of visual evoked potential peaks N1 and P2, and a reduced amount of fast-wave activity on the electroencephalogram). Baseline plasma phenylalanine and Tyr concentrations were in the typical range of adult patients with PKU. The plasma Tyr concentration increased approximately 200% during Tyr supplementation, but no beneficial effects were observed. CONCLUSIONS High-dose Tyr supplementation cannot be recommended as an "alternative" treatment for patients with PKU after relaxation or termination of strict dietary adherence.
Collapse
Affiliation(s)
- J Pietz
- Department of Pediatric Neurology, University of Heidelberg, Germany
| | | | | | | | | | | |
Collapse
|
15
|
Effects of L-arginine and of its functional antagonist N-nitro-L-arginine on the behavior of rats, with special reference to motor activity. Bull Exp Biol Med 1995. [DOI: 10.1007/bf02445471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
16
|
Greve LC, Wheeler MD, Green-Burgeson DK, Zorn EM. Breast-feeding in the management of the newborn with phenylketonuria: a practical approach to dietary therapy. JOURNAL OF THE AMERICAN DIETETIC ASSOCIATION 1994; 94:305-9. [PMID: 8120296 DOI: 10.1016/0002-8223(94)90373-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Guidelines introduced in 1979 for breast-feeding infants with phenylketonuria included a formula containing low amounts of phenylalanine (PHE) as part of the dietary prescription. Although the guidelines were revised in 1988, new PHE-free products were not included. In addition, the guidelines recommend infant weight checks before and after feeding to ensure correct dietary intake of breast milk. In this study, we present data based on treatment of 13 infants for the first 6 months of life using a PHE-free product and human milk (n = 9) or commercial formula (n = 4). The study began with nine breast-fed infants; five were weaned before 6 months of age and were discontinued from the study. Published estimates of volume and energy of daily human milk consumption were used to prescribe and assess intake of breast milk. No differences were noted between the groups in blood levels of PHE at initiation of dietary therapy, age at initiation of dietary therapy, or length of time to achieve metabolic control. Furthermore, blood levels of PHE and growth parameters for each month up to 6 months of age were similar for both groups. These data support the efficacy of PHE-free formula and estimation of breast milk volumes in managing the diet of infants with phenylketonuria.
Collapse
Affiliation(s)
- L C Greve
- Department of Pediatrics, University of California-Davis Medical Center, Sacramento 95817
| | | | | | | |
Collapse
|
17
|
Pietz J, Schmidt E, Matthis P, Kobialka B, Kutscha A, de Sonneville L. EEGs in phenylketonuria. I: Follow-up to adulthood; II: Short-term diet-related changes in EEGs and cognitive function. Dev Med Child Neurol 1993; 35:54-64. [PMID: 8449380 DOI: 10.1111/j.1469-8749.1993.tb11552.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The authors report the results of two EEG studies on adult patients with phenylketonuria (PKU) who had been treated early. Part I: the authors followed the EEGs of 34 PKU patients from birth to age 21. The frequency of abnormal EEG findings (especially epileptiform activity) steadily increased until age 12, then decreased. IQ correlated significantly with quality of dietary control during follow-up. Part II: frequency analysis of the EEG and neuropsychological testing were performed on eight adult patients after periods of four weeks with low and high levels of phenylalanine. Only five patients followed the strict dietary regulations. With high levels of phenylalanine, the dominant peak of EEG background activity shifted to the slower frequency spectrum in all patients; in addition, neuropsychological testing revealed impairment of cognitive function. The significance of different approaches of EEG examinations is discussed with respect to the problems of monitoring PKU patients and the pathogenic mechanisms of CNS damage in phenylketonuria.
Collapse
Affiliation(s)
- J Pietz
- Department of Paediatric Neurology, Children's Hospital, University of Heidelberg, Germany
| | | | | | | | | | | |
Collapse
|
18
|
Richardson MA, Flynn CJ, Read L. Comment on 'The ratio of plasma phenylalanine to other large neutral amino acids is not a risk factor for tardive dyskinesia'. J Psychopharmacol 1993; 7:219-20. [PMID: 22290672 DOI: 10.1177/026988119300700213] [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: 11/15/2022]
Affiliation(s)
- M A Richardson
- Movement Disorders Program, N.S. Kline Institute for Psychiatric Research, Department of Psychiatry, N Y University Medical Center, Clinical Movement Disorders Program, Rockland Psychiatric Center, New York, USA
| | | | | |
Collapse
|
19
|
Epstein CM, Riether AM, Henderson RM, Cotsonis GA. EEG in liver transplantation: visual and computerized analysis. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1992; 83:367-71. [PMID: 1281082 DOI: 10.1016/0013-4694(92)90072-p] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
We prospectively evaluated 40 liver transplant candidates (including 28 recipients) with visually scored or computerized EEG. As expected, EEG frequencies rose significantly after successful transplant (P < 0.01). For all subjects, but especially for the transplant recipients, higher frequencies on computerized EEG at baseline had a strong association with survival at 18 months (P < 0.001). A logistic regression model allowed estimation of the odds for survival and indicated less than 50% long-term survival with central-occipital mean frequencies below 7.6 c/sec. Visual EEG scores closely paralleled the quantitative results, but only the latter were amenable to formal statistical analysis. EEG had much stronger predictive value for survival than serum albumin, although albumin improved more significantly in the months after transplantation.
Collapse
Affiliation(s)
- C M Epstein
- Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322
| | | | | | | |
Collapse
|
20
|
Salinsky MC, Oken BS, Morehead L. Test-retest reliability in EEG frequency analysis. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1991; 79:382-92. [PMID: 1718711 DOI: 10.1016/0013-4694(91)90203-g] [Citation(s) in RCA: 181] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
This study was performed to gain a better understanding of EEG frequency analysis test-retest reliability in normal healthy adults, and to evaluate factors which could influence the measured inter-record differences. Nineteen subjects underwent serial EEG recordings at 5 min and 12-16 week intervals. Records were visually edited using a standardized protocol, and FFT frequency analysis performed on segments of 60, 40, or 20 sec total length. Correlation coefficients for broad band features averaged 0.92 over the 5 min retest interval and 0.84 over the 12-16 week interval. There was essentially no difference between correlation coefficients of absolute and relative power features. Coefficients based on 60 sec records were marginally higher than those of 40 or 20 sec records. On the other hand, test-retest percent differences were typically lower for relative as opposed to absolute power features, and 60 sec records showed consistently lower percent differences than did 40 or particularly 20 sec records. Peak alpha frequency and mean frequency were the most stable EEG features at either interval. Montage had significant effects on test-retest differences at the 12-16 week interval. A significant association between intra-record and inter-record variability could not be demonstrated.
Collapse
Affiliation(s)
- M C Salinsky
- Veterans Affairs Medical Center, Portland, OR 97201
| | | | | |
Collapse
|