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Manti F, Nardecchia F, De Leo S, Carducci C, Romani C, Palermo L, Angeloni A, Leuzzi V. Towards precision medicine for phenylketonuria: The effect of restoring a strict metabolic control in adult patients with early-treated phenylketonuria. Mol Genet Metab 2023; 140:107666. [PMID: 37549444 DOI: 10.1016/j.ymgme.2023.107666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Revised: 07/23/2023] [Accepted: 07/24/2023] [Indexed: 08/09/2023]
Abstract
BACKGROUND AND OBJECTIVE Neonatal screening and early treatment have changed the natural history of PKU, preventing severe neurological and intellectual disability. Nevertheless, the outcome of the disease in early-treated adult patients (ETPKU) is less than optimal, the predictive value of metabolic biomarkers is feeble, and the recommended levels of blood phenylalanine (Phe) for adulthood are controversial. A crucial question whose answer will improve our understanding and treatment of PKU is whether cognitive outcomes can be modulated by levels of Phe even in early-treated adults. To address this question, we carried out an interventional study in seven ETPKU women planning a pregnancy. METHODS They underwent an extensive neurocognitive assessment at baseline, and 3 and 6 months after having attained the blood Phe concentration recommended to prevent PKU fetopathy, but before pregnancy. RESULTS After 3 and 6 months with a stable blood Phe level of about 240 μmol/L, all participants experienced significant improvements in almost all neurocognitive domains and tasks. IQ also increased of 11 to 21 points from the last assessment before enrolment. This pattern remained strong and consistent after correction for multiple comparisons. CONCLUSION Our results indicate that a) strong cognitive improvement is possible even in adulthood and may be demonstrated by lowering Phe near normal levels; b) testing cognition under different metabolic conditions may unveil an individual vulnerability to Phe. These results pave the way for personalised treatment of the disease in adults with ETPKU.
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Affiliation(s)
- Filippo Manti
- Department of Human Neuroscience - Unit of Child Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy
| | - Francesca Nardecchia
- Department of Human Neuroscience - Unit of Child Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy
| | - Sabrina De Leo
- Department of Clinical Medicine, Azienda Ospedaliero Universitaria Policlinico Umberto I, Rome, Italy
| | - Claudia Carducci
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | - Cristina Romani
- School of Life and Health Sciences, Aston University, Birmingham, UK
| | - Liana Palermo
- Department of Medical and Surgical Sciences, Magna Graecia University of Catanzaro, Catanzaro, Italy
| | - Antonio Angeloni
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | - Vincenzo Leuzzi
- Department of Human Neuroscience - Unit of Child Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy.
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Grant ML, Jurecki ER, McCandless SE, Stahl SM, Bilder DA, Sanchez-Valle A, Dimmock D. Neuropsychiatric Function Improvement in Pediatric Patients with Phenylketonuria. J Pediatr 2023; 260:113526. [PMID: 37263523 DOI: 10.1016/j.jpeds.2023.113526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 05/19/2023] [Accepted: 05/24/2023] [Indexed: 06/03/2023]
Abstract
OBJECTIVE To evaluate effects of sapropterin dihydrochloride on blood phenylalanine (Phe) and symptoms of neuropsychiatric impairment in children and adolescents with phenylketonuria (PKU). STUDY DESIGN PKU subjects 8-17 years of age (n = 86) were randomized to double-blind treatment with sapropterin (n = 43) or placebo (n = 43) for 13 weeks, then all received open-label sapropterin therapy for an additional 13 weeks. Blood Phe and symptoms of inattention, hyperactivity/impulsivity (Attention-Deficit/Hyperactivity Disorder Rating Scale IV [ADHD RS-IV]), executive functioning (Behavior Rating Inventory of Executive Function), depression (Hamilton Rating Scale for Depression), and anxiety (Hamilton Rating Scale for Anxiety) were assessed. RESULTS Following the 13-week randomization phase, the sapropterin and placebo groups had mean changes in blood Phe of -20.9% and +2.9%, respectively. Corresponding least square mean differences in ADHD RS-IV scores were significantly greater for the sapropterin vs the placebo group: Total (-3.2 points, P = .02), Inattention subscale (-1.8 points, P = .04), and Hyperactivity/Impulsivity subscale (-1.6 points, P = .02). Forest plots favored sapropterin treatment over placebo for all ADHD RS-IV and Behavior Rating Inventory of Executive Function indices. There were no significant differences in reported problems with attention or executive function between the 2 groups at baseline or at week 26 following the 13-week open-label treatment period. Anxiety and depression scores did not differ significantly between cohorts at any time. Sapropterin was well tolerated, with a favorable safety profile. CONCLUSIONS Sapropterin reduced blood Phe and was associated with significant improvement in parent-reported symptoms of inattention, hyperactivity/impulsivity, and executive functioning in children and adolescents with PKU. TRIAL REGISTRATION ClinicalTrials.gov, NCT01114737. Registered 27 April 2010, https://clinicaltrials.gov/ct2/show/NCT01114737.
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Affiliation(s)
| | | | - Shawn E McCandless
- University of Colorado, Anschutz Medical Campus and Children's Hospital Colorado, Aurora, CO
| | - Stephen M Stahl
- Department of Psychiatry, University of California San Diego, San Diego, CA
| | - Deborah A Bilder
- Department of Psychiatry, Division of Child & Adolescent Psychiatry, University of Utah, Salt Lake City, UT
| | - Amarilis Sanchez-Valle
- Department of Pediatrics, Division of Genetics and Metabolism, University of South Florida, Tampa, FL
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Cognitive Functioning in Adults with Phenylketonuria in a Cohort of Spanish Patients. Behav Neurol 2023; 2023:9681740. [PMID: 36815863 PMCID: PMC9931468 DOI: 10.1155/2023/9681740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 12/14/2022] [Accepted: 12/15/2022] [Indexed: 02/10/2023] Open
Abstract
The early introduction of a low phenylalanine (Phe) diet has been demonstrated to be the most successful treatment in subjects with phenylketonuria (PKU), especially for preventing severe cognitive and neurological damages. However, it still concerns that even if treated in the first months of life with supplements and following a diet, they can show slight scores below people without PKU in neuropsychological assignments. We investigated 20 adults with classical PKU aged 19-48 years (mean age 29 years) and 20 heathy controls matched by age, gender, and years of education. Patients and controls were assessed with an extended neuropsychological battery, as well as psychological aspects and quality of life, also the last Phe level result was obtained. Results showed that the most affected cognitive domains are processing speed, executive functioning, memory, and also theory of mind, but very well-preserved verbal fluency, language, and visuospatial functioning. In quality of life, some significant results were seen specially in anxiety of Phe levels, anxiety of Phe levels during pregnancy, guilt if poor adherence to supplements, and if dietary protein restriction not followed. No significant results were obtained for the psychological variables. In conclusion, it has been shown that a combination of a low Phe diet, supplement intake, and keeping Phe levels in a low range seems appropriate to have the most normal and alike cognitive performance to persons without PKU.
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Thomas L, Olson A, Romani C. The impact of metabolic control on cognition, neurophysiology, and well-being in PKU: A systematic review and meta-analysis of the within-participant literature. Mol Genet Metab 2023; 138:106969. [PMID: 36599257 DOI: 10.1016/j.ymgme.2022.106969] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 12/09/2022] [Accepted: 12/10/2022] [Indexed: 12/15/2022]
Abstract
Phenylketonuria (PKU) is a metabolic disease where Phenylalanine (Phe) rises much above normal levels. Cross-sectional and correlational studies provide valuable information on the importance of maintaining low blood-Phe to achieve good outcomes, but they may be confounded, at least partially, by differences in participant demographics. Moreover, the effect of Phe at older ages is difficult to ascertain because of strong associations between Phe levels across ages. Within-participant studies avoid confounding issues. We have reviewed these studies. We followed PRISMA guidelines to search the literature for studies reporting the impact of Phe changes within participants. Phe was either increased or decreased through diet relaxation/resumption or through pharmacological interventions. Forty-six separate articles reported, singly or in combination, results on cognition (N = 37), well-being (N = 22) and neurophysiological health (N = 14). For all studies, we established, in a binary way, whether a benefit of lower Phe was or was not demonstrated and compared numbers showing benefit versus a null or negative outcome. We then analyzed whether critical parameters (e.g., length of the study/condition for the change, size of Phe change achieved) influenced presence or absence of benefit. For a subset of studies that reported quantitative cognitive outcomes, we carried out a meta-analysis to estimate the size of change in cognitive performance associated with a change in Phe and its significance. There were significantly more studies with benefits than no benefits, both for cognitive and well-being outcomes, and a trend in this direction for neurophysiological outcomes. The meta-analysis showed a highly significant effect size both overall (0.55) and when studies with adults/adolescents were considered separately (0.57). There was some indication that benefits were easier to demonstrate when differences in Phe were larger and achieved across a longer period, but these effects were not always consistent. These results reinforce results from the literature by demonstrating the importance of lower Phe in children as well as in adolescents and adults, even when confounding factors in group composition are eliminated. The field would benefit from further studies where Phe levels are contrasted within-participants to ascertain how much Phe needs to be changed and for how long to see a difference and which measures demonstrate a difference (e.g., which cognitive tasks).
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Romani C, Olson A, Aitkenhead L, Baker L, Patel D, Spronsen FV, MacDonald A, Wegberg AV, Huijbregts S. Meta-analyses of cognitive functions in early-treated adults with phenylketonuria. Neurosci Biobehav Rev 2022; 143:104925. [PMID: 36283539 DOI: 10.1016/j.neubiorev.2022.104925] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Revised: 10/07/2022] [Accepted: 10/21/2022] [Indexed: 11/05/2022]
Abstract
Our study estimated size of impairment for different cognitive functions in early-treated adults with PKU (AwPKU) by combining literature results in a meta-analytic way. We analysed a large set of functions (N = 19), each probed by different measures (average = 12). Data were extracted from 26 PKU groups and matched controls, with 757 AwPKU contributing 220 measures. Effect sizes (ESs) were computed using Glass' ∆ where differences in performance between clinical/PKU and control groups are standardized using the mean and standard deviation of the control groups. Significance was assessed using measures nested within independent PKU groups as a random factor. The weighted Glass' ∆ was - 0.44 for all functions taken together, and - 0.60 for IQ, both highly significant. Separate, significant impairments were found for most functions, but with great variability (ESs from -1.02 to -0.18). The most severe impairments were in reasoning, visual-spatial attention speed, sustained attention, visuo-motor control, and flexibility. Effect sizes were larger with speed than accuracy measures, and with visuo-spatial than verbal stimuli. Results show a specific PKU profile that needs consideration when monitoring the disease.
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Affiliation(s)
| | - Andrew Olson
- Psychology Department, University of Birmingham, UK.
| | | | - Lucy Baker
- Psychology Department, Aston University, UK.
| | | | | | - Anita MacDonald
- Birmingham Women' s and Children's NHS Foundation Trust, UK.
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A comprehensive assessment of neurocognitive and psychological functioning in adults with early-treated phenylketonuria. J Int Neuropsychol Soc 2022:1-10. [PMID: 36134437 DOI: 10.1017/s1355617722000686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE Relative to youth with early-treated phenylketonuria (ETPKU), much less is known regarding the cognitive profile of adults with ETPKU. The present study aimed to address this gap by providing a comprehensive assessment of neuropsychological functioning among adults with ETPKU. METHOD A sample of 40 adults with ETPKU (ages 18 - 36) and a demographically matched group of 32 healthy individuals without PKU participated. Participants completed a comprehensive neuropsychological battery including the NIH Toolbox, Wechsler Abbreviated Scale of Intelligence - Second Edition (WASI-II), Conners' Continuous Performance Test (CPT-3), select subtests from the Weschler Adult Intelligence Scale - Fourth Edition (WAIS-IV) as well as several self-report measures of cognitive and psychoemotional functioning. Scores from these tests were combined to create cognitive composites reflecting overall task performance in the areas of verbal ability, visuospatial skills, executive functioning, motor skills, and processing speed. RESULTS No group differences were observed for full scale IQ or verbal ability. However, individuals with ETPKU demonstrated poorer performance on measures of executive functioning, processing speed, motor skills, and visuospatial skills as compared to the non-PKU group. Within the ETPKU group, recent blood phenylalanine levels (an indicator of metabolic control) were significantly correlated with performance across most cognitive domains and aspects of psychological functioning. CONCLUSIONS Present findings suggest that the neuropsychological profile of adult ETPKU is characterized by circumscribed impairments in select cognitive domains. In addition, the results underscore the importance of maintaining metabolic control across the lifespan in individuals with ETPKU.
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Hopf S, Nowak C, Hennermann JB, Schmidtmann I, Pfeiffer N, Pitz S. Saccadic reaction time and ocular findings in phenylketonuria. Orphanet J Rare Dis 2020; 15:124. [PMID: 32450880 PMCID: PMC7249436 DOI: 10.1186/s13023-020-01407-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 05/11/2020] [Indexed: 01/12/2023] Open
Abstract
Background Phenylketonuria (PKU) is an inherited metabolic disorder characterized by reduced activity of phenylalanine hydroxylase resulting in elevated blood phenylalanine (Phe) concentration. Despite some obvious ocular changes, the disorder has been poorly recognized by ophthalmologists. Neurophysiologic tests imply prolonged reaction time correlating with increased phenylalanine blood concentrations. We aimed to test saccadic reaction time in PKU patients in dependency of blood phenylalanine concentrations. Methods Nineteen biochemically diagnosed PKU patients and 100 controls completed comprehensive ophthalmologic and orthoptic examinations including saccadometry by infrared based video-oculography. Peak velocity, gain, and particularly latency of reflexive saccades were compared to controls, and regression analysis was performed. Results Latency of reflexive saccades was not associated with the current phenylalanine concentration. Although in 10 out of 19 patients phenylalanine concentrations were outside the age-related therapeutic range, latency differed little between PKU patients and the controls, as well as peak velocity and gain. Ocular findings occurred as partial hypopigmentation of the iris in one late diagnosed patient aged 36 years, and as bilateral cataracts (possibly due to steroid intake) with refractive amblyopia, strabismus, high myopia, and glaucoma in another late diagnosed patient aged 46 years. Visual acuity was reduced in eight PKU patients. Conclusions Saccadometry, particularly saccadic reaction time, is not useful in the monitoring of phenylketonuria. Ophthalmic examination is recommended in PKU patients, as the occurrence of ocular pathologies was relatively high.
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Affiliation(s)
- Susanne Hopf
- Department of Ophthalmology, University Medical Center Mainz, Langenbeckstr 1, 55131, Mainz, Germany.
| | | | - Julia B Hennermann
- Villa Metabolica, Department of Pediatric and Adolescent Medicine, University Medical Center Mainz, Mainz, Germany
| | - Irene Schmidtmann
- Institute of Medical Biostatistics, Epidemiology and Informatics (IMBEI), University Medical Center Mainz, Mainz, Germany
| | - Norbert Pfeiffer
- Department of Ophthalmology, University Medical Center Mainz, Langenbeckstr 1, 55131, Mainz, Germany
| | - Susanne Pitz
- Department of Ophthalmology, University Medical Center Mainz, Langenbeckstr 1, 55131, Mainz, Germany.,Orbital Center, Ophthalmic Clinic, Bürgerhospital Frankfurt, Frankfurt, Germany
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Xiang L, Tao J, Deng K, Li X, Li Q, Yuan X, Liang J, Yu E, Wang M, Wang H, Liu H, Zhu J. Phenylketonuria incidence in China between 2013 and 2017 based on data from the Chinese newborn screening information system: a descriptive study. BMJ Open 2019; 9:e031474. [PMID: 31444193 PMCID: PMC6707664 DOI: 10.1136/bmjopen-2019-031474] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 07/02/2019] [Accepted: 07/17/2019] [Indexed: 11/25/2022] Open
Abstract
OBJECTIVE This study examines the incidence and spatial clustering of phenylketonuria (PKU) in China between 2013 and 2017. METHODS Data from the Chinese Newborn Screening Information System were analysed to assess PKU incidence with 95% CIs by province, region and disease severity. Spatial clustering of PKU cases was analysed using global and local spatial autocorrelation analysis in the geographic information system. RESULTS The database contained 4925 neonates with confirmed PKU during the study period, corresponding to an incidence of 6.28 (95% CI: 6.11 to 6.46) per 100 000 neonates screened. Incidence was highest in the provinces of Gansu, Ningxia and Qinghai, where it ranged from 19.00 to 28.63 per 100 000 neonates screened. Overall incidence was higher in the northern part of the country, where classical disease predominated, than in the southern part, where mild disease predominated. PKU cases clustered spatially (global Moran's I=0.3603, Z=5.3097, p<0.001), and local spatial autocorrelation identified four northern provinces as high-high clusters (Gansu, Qinghai, Ningxia and Shanxi). CONCLUSIONS China shows an intermediate PKU incidence among countries, and incidence differs substantially among Chinese provinces and between northern and southern regions. Our results suggest the need to focus efforts on screening, diagnosing and treating PKU in high-incidence provinces.
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Affiliation(s)
- Liangcheng Xiang
- National Office for Maternal and Child Health Surveillance of China, Sichuan University West China Second University Hospital, Chengdu, China
| | - Jing Tao
- National Office for Maternal and Child Health Surveillance of China, Sichuan University West China Second University Hospital, Chengdu, China
| | - Kui Deng
- National Office for Maternal and Child Health Surveillance of China, Sichuan University West China Second University Hospital, Chengdu, China
| | - Xiaohong Li
- National Office for Maternal and Child Health Surveillance of China, Sichuan University West China Second University Hospital, Chengdu, China
| | - Qi Li
- National Office for Maternal and Child Health Surveillance of China, Sichuan University West China Second University Hospital, Chengdu, China
| | - Xuelian Yuan
- National Office for Maternal and Child Health Surveillance of China, Sichuan University West China Second University Hospital, Chengdu, China
| | - Juan Liang
- National Office for Maternal and Child Health Surveillance of China, Sichuan University West China Second University Hospital, Chengdu, China
| | - Erling Yu
- National Office for Maternal and Child Health Surveillance of China, Sichuan University West China Second University Hospital, Chengdu, China
| | - Meixian Wang
- National Office for Maternal and Child Health Surveillance of China, Sichuan University West China Second University Hospital, Chengdu, China
| | - Huiqing Wang
- Department of Pediatrics, Sichuan University West China Second University Hospital, Chengdu, China
| | - Hanmin Liu
- Department of Pediatrics, Sichuan University West China Second University Hospital, Chengdu, China
- Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Sichuan University West China Second University Hospital, Chengdu, China
| | - Jun Zhu
- National Office for Maternal and Child Health Surveillance of China, Sichuan University West China Second University Hospital, Chengdu, China
- Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Sichuan University West China Second University Hospital, Chengdu, China
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Hofman DL, Champ CL, Lawton CL, Henderson M, Dye L. A systematic review of cognitive functioning in early treated adults with phenylketonuria. Orphanet J Rare Dis 2018; 13:150. [PMID: 30165883 PMCID: PMC6117942 DOI: 10.1186/s13023-018-0893-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 08/16/2018] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Even though early dietary management of phenylketonuria (PKU) successfully prevents severe neurological impairments, deficits in cognitive functioning are still observed. These deficits are believed to be the result of elevated levels of phenylalanine throughout life. Research on cognitive functioning in adults with PKU (AwPKU) often focuses on domains shown to be compromised in children with PKU, such as attention and executive functions, whereas other cognitive domains have received less attention. This systematic review aimed to provide an overview of cognitive functioning across domains examined in early treated (ET) AwPKU. METHODS A systematic search was performed in Ovid MEDLINE(R), PsycINFO, Web of Science, Cochrane, Scopus, Embase, ScienceDirect, and PubMed for observational studies on cognitive performance in ET AwPKU. RESULTS Twenty-two peer-reviewed publications, reporting on outcomes from 16 studies were reviewed. Collectively, the results most consistently showed deficits in vigilance, working memory and motor skills. Deficits in other cognitive domains were less consistently observed or were understudied. Furthermore, despite reports of several associations between cognitive performance and phenylalanine (Phe) levels throughout life the relationship remains unclear. Inconsistencies in findings across studies could be explained by the highly heterogeneous nature of study samples, resulting in large inter- and intra-variability in Phe levels, as well as the use of a variety of tests across cognitive domains, which differ in sensitivity. The long-term cognitive outcomes of early and continuous management of PKU remain unclear. CONCLUSIONS To better understand the development of cognitive deficits in ET AwPKU, future research would benefit from 1) (inter)national multicentre-studies; 2) more homogeneous study samples; 3) the inclusion of other nutritional measures that might influence cognitive functioning (e.g. Phe fluctuations, Phe:Tyrosine ratio and micronutrients such as vitamin B12); and 4) careful selection of appropriate cognitive tests.
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Affiliation(s)
| | | | | | - Mick Henderson
- Biochemical Genetics, Specialist Laboratory Medicine, St James’s University Hospital, Block 46, Leeds, LS9 7TF UK
| | - Louise Dye
- School of Psychology, University of Leeds, Leeds, LS2 9JT UK
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10
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Individual differences in human eye movements: An oculomotor signature? Vision Res 2017; 141:157-169. [DOI: 10.1016/j.visres.2017.03.001] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 02/28/2017] [Accepted: 03/04/2017] [Indexed: 12/12/2022]
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11
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van Vliet D, van der Goot E, Bruinenberg VM, van Faassen M, de Blaauw P, Kema IP, Heiner-Fokkema MR, van der Zee EA, van Spronsen FJ. Large neutral amino acid supplementation as an alternative to the phenylalanine-restricted diet in adults with phenylketonuria: evidence from adult Pah-enu2 mice. J Nutr Biochem 2017; 53:20-27. [PMID: 29175141 DOI: 10.1016/j.jnutbio.2017.09.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 09/04/2017] [Accepted: 09/28/2017] [Indexed: 11/26/2022]
Abstract
Phenylketonuria treatment mainly consists of a phenylalanine-restricted diet but still results in suboptimal neuropsychological outcome, which is at least partly based on cerebral monoamine deficiencies, while, after childhood, treatment compliance decreases. Supplementation of large neutral amino acids (LNAAs) was previously demonstrated in young phenylketonuria mice to target all three biochemical disturbances underlying brain dysfunction in phenylketonuria. However, both its potential in adult phenylketonuria and the comparison with the phenylalanine-restricted diet remain to be established. To this purpose, several LNAA supplements were compared with a severe phenylalanine-restricted diet with respect to brain monoamine and amino acid concentrations in adult C57Bl/6 Pah-enu2 mice. Adult phenylketonuria mice received a phenylalanine-restricted diet, unrestricted diet supplemented with several combinations of LNAAs or AIN-93M control diet for 6 weeks. In addition, adult wild-type mice on AIN-93M diet served as controls. The severe phenylalanine-restricted diet in adult phenylketonuria mice significantly reduced plasma and brain phenylalanine and restored brain monoamine concentrations, while brain concentrations of most nonphenylalanine LNAAs remained subnormal. Supplementation of eight LNAAs was similarly effective as the severe phenylalanine-restricted diet to restore brain monoamines, while brain and plasma phenylalanine concentrations remained markedly elevated. These results provide biochemical support for the effectiveness of the severe phenylalanine-restricted diet and showed the possibilities of LNAA supplementation being equally effective to restore brain monoamines in adult phenylketonuria mice. Therefore, LNAA supplementation is a promising alternative treatment to phenylalanine restriction in adult phenylketonuria patients to further optimize neuropsychological functioning.
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Affiliation(s)
- Danique van Vliet
- University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Groningen, the Netherlands
| | - Els van der Goot
- University of Groningen, Groningen Institute for Evolutionary Life Sciences (GELIFES), Department of Molecular Neurobiology, Groningen, the Netherlands
| | - Vibeke M Bruinenberg
- University of Groningen, Groningen Institute for Evolutionary Life Sciences (GELIFES), Department of Molecular Neurobiology, Groningen, the Netherlands
| | - Martijn van Faassen
- University of Groningen, University Medical Center Groningen, Department of Laboratory Medicine, Groningen, the Netherlands
| | - Pim de Blaauw
- University of Groningen, University Medical Center Groningen, Department of Laboratory Medicine, Groningen, the Netherlands
| | - Ido P Kema
- University of Groningen, University Medical Center Groningen, Department of Laboratory Medicine, Groningen, the Netherlands
| | - M Rebecca Heiner-Fokkema
- University of Groningen, University Medical Center Groningen, Department of Laboratory Medicine, Groningen, the Netherlands
| | - Eddy A van der Zee
- University of Groningen, Groningen Institute for Evolutionary Life Sciences (GELIFES), Department of Molecular Neurobiology, Groningen, the Netherlands
| | - Francjan J van Spronsen
- University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Groningen, the Netherlands.
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van Wegberg AMJ, MacDonald A, Ahring K, Bélanger-Quintana A, Blau N, Bosch AM, Burlina A, Campistol J, Feillet F, Giżewska M, Huijbregts SC, Kearney S, Leuzzi V, Maillot F, Muntau AC, van Rijn M, Trefz F, Walter JH, van Spronsen FJ. The complete European guidelines on phenylketonuria: diagnosis and treatment. Orphanet J Rare Dis 2017; 12:162. [PMID: 29025426 PMCID: PMC5639803 DOI: 10.1186/s13023-017-0685-2] [Citation(s) in RCA: 411] [Impact Index Per Article: 58.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 07/11/2017] [Indexed: 12/22/2022] Open
Abstract
Phenylketonuria (PKU) is an autosomal recessive inborn error of phenylalanine metabolism caused by deficiency in the enzyme phenylalanine hydroxylase that converts phenylalanine into tyrosine. If left untreated, PKU results in increased phenylalanine concentrations in blood and brain, which cause severe intellectual disability, epilepsy and behavioural problems. PKU management differs widely across Europe and therefore these guidelines have been developed aiming to optimize and standardize PKU care. Professionals from 10 different European countries developed the guidelines according to the AGREE (Appraisal of Guidelines for Research and Evaluation) method. Literature search, critical appraisal and evidence grading were conducted according to the SIGN (Scottish Intercollegiate Guidelines Network) method. The Delphi-method was used when there was no or little evidence available. External consultants reviewed the guidelines. Using these methods 70 statements were formulated based on the highest quality evidence available. The level of evidence of most recommendations is C or D. Although study designs and patient numbers are sub-optimal, many statements are convincing, important and relevant. In addition, knowledge gaps are identified which require further research in order to direct better care for the future.
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Affiliation(s)
- A. M. J. van Wegberg
- Division of Metabolic Diseases, Beatrix Children’s Hospital, University Medical Center Groningen, PO BOX 30.001, 9700 RB Groningen, The Netherlands
| | - A. MacDonald
- Dietetic Department, Birmingham Children’s Hospital, Birmingham, UK
| | - K. Ahring
- Department of PKU, Kennedy Centre, Glostrup, Denmark
| | - A. Bélanger-Quintana
- Metabolic Diseases Unit, Department of Paediatrics, Hospital Ramon y Cajal Madrid, Madrid, Spain
| | - N. Blau
- University Children’s Hospital, Dietmar-Hoppe Metabolic Centre, Heidelberg, Germany
- University Children’s Hospital Zürich, Zürich, Switzerland
| | - A. M. Bosch
- Department of Paediatrics, Division of Metabolic Disorders, Academic Medical Centre, University Hospital of Amsterdam, Amsterdam, The Netherlands
| | - A. Burlina
- Division of Inherited Metabolic Diseases, Department of Paediatrics, University Hospital of Padova, Padova, Italy
| | - J. Campistol
- Neuropaediatrics Department, Hospital Sant Joan de Déu, Universitat de Barcelona, Barcelona, Spain
| | - F. Feillet
- Department of Paediatrics, Hôpital d’Enfants Brabois, CHU Nancy, Vandoeuvre les Nancy, France
| | - M. Giżewska
- Department of Paediatrics, Endocrinology, Diabetology, Metabolic Diseases and Cardiology of the Developmental Age, Pomeranian Medical University, Szczecin, Poland
| | - S. C. Huijbregts
- Department of Clinical Child and Adolescent Studies-Neurodevelopmental Disorders, Faculty of Social Sciences, Leiden University, Leiden, The Netherlands
| | - S. Kearney
- Clinical Psychology Department, Birmingham Children’s Hospital, Birmingham, UK
| | - V. Leuzzi
- Department of Paediatrics, Child Neurology and Psychiatry, Sapienza University of Rome, Via dei Sabelli 108, 00185 Rome, Italy
| | - F. Maillot
- CHRU de Tours, Université François Rabelais, INSERM U1069, Tours, France
| | - A. C. Muntau
- University Children’s Hospital, University Medical Centre Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - M. van Rijn
- Division of Metabolic Diseases, Beatrix Children’s Hospital, University Medical Center Groningen, PO BOX 30.001, 9700 RB Groningen, The Netherlands
| | - F. Trefz
- Department of Paediatrics, University of Heidelberg, Heidelberg, Germany
| | - J. H. Walter
- Medicine, Manchester Academic Health Sciences Centre, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
| | - F. J. van Spronsen
- Division of Metabolic Diseases, Beatrix Children’s Hospital, University Medical Center Groningen, PO BOX 30.001, 9700 RB Groningen, The Netherlands
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Caprile C, Campistol J, Puigcerver L, Gutiérrez-Mata AP, Alonso-Colmenero I, Colomé R, Navarra J. Subtle visuomotor deficits and reduced benefit from practice in early treated phenylketonuria. J Clin Exp Neuropsychol 2017; 39:931-940. [PMID: 28165881 DOI: 10.1080/13803395.2017.1281381] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
INTRODUCTION Phenylketonuria (PKU) is a rare metabolic disease that causes slight-to-severe neurological symptoms. Slow performance has been observed in PKU but the influence of high-order (i.e., not purely motor) deficits and of temporary variations of the phenylalanine (Phe) level on this slowness has not been fully corroborated as yet. Response speed and the effect of motor practice during the performance of a visuomotor coordination task were measured, in a group of patients with early-treated phenylketonuria (ET PKU). METHOD We compared the performance of a group of early-treated PKU patients with ages ranging from 11 to 25 years and a control group of healthy volunteers on a computerized visuomotor task. Participants performed rapid movements towards one of five response buttons, as indicated by a visual stimulus that could appear in five different positions on a computer screen. The results of our visuomotor task were correlated with neurobiological data (Phe levels) and with neuropsychological measures of motor (finger tapping) and executive functions (Stroop task). RESULTS The ET PKU group showed slower responses than the control group. Furthermore, an absence of a practice effect (i.e., faster response times at the end of the study) was found in the PKU group but not in the control group. Our results also revealed that this absence of practice effect correlated with higher Phe levels on the testing day with respect to the average Phe level of the previous 12 months and, although weakly, with performance on the Stroop task. CONCLUSIONS This pattern of results indicates slower visuomotor performance and a less beneficial effect of practice in ET PKU. The correlations found among our visuomotor measures, the same-day Phe level, and the Stroop test may reflect the negative effects of dopamine reduction in brain areas involved in motor control, selective attention, and learning.
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Affiliation(s)
- Claudia Caprile
- a Experimental Psychology & Brain Disorders Laboratory , Fundació Sant Joan de Déu, Hospital Sant Joan de Déu , Esplugues de Llobregat, Barcelona , Spain
| | - Jaume Campistol
- b Servei de Neurologia Pediàtrica , Hospital Sant Joan de Déu , Esplugues de Llobregat, Barcelona , Spain
| | - Laura Puigcerver
- a Experimental Psychology & Brain Disorders Laboratory , Fundació Sant Joan de Déu, Hospital Sant Joan de Déu , Esplugues de Llobregat, Barcelona , Spain.,c Department of Cognition, Development and Educational Psychology , University of Barcelona , Barcelona , Spain
| | | | - Itziar Alonso-Colmenero
- b Servei de Neurologia Pediàtrica , Hospital Sant Joan de Déu , Esplugues de Llobregat, Barcelona , Spain
| | - Roser Colomé
- e UTAE Learning Disorders Unit , Hospital Sant Joan de Déu , Barcelona , Spain
| | - Jordi Navarra
- a Experimental Psychology & Brain Disorders Laboratory , Fundació Sant Joan de Déu, Hospital Sant Joan de Déu , Esplugues de Llobregat, Barcelona , Spain.,c Department of Cognition, Development and Educational Psychology , University of Barcelona , Barcelona , Spain
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14
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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] [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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15
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Howard R, Chataway J, Edwards M, Heales S, Lachmann R, Leff A, Murphy E. Toxic, Metabolic and Physical Insults to the Nervous System and Inherited Disorders of Metabolism. Neurology 2016. [DOI: 10.1002/9781118486160.ch19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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16
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Singh RH, Cunningham AC, Mofidi S, Douglas TD, Frazier DM, Hook DG, Jeffers L, McCune H, Moseley KD, Ogata B, Pendyal S, Skrabal J, Splett PL, Stembridge A, Wessel A, Rohr F. Updated, web-based nutrition management guideline for PKU: An evidence and consensus based approach. Mol Genet Metab 2016; 118:72-83. [PMID: 27211276 DOI: 10.1016/j.ymgme.2016.04.008] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 04/15/2016] [Accepted: 04/15/2016] [Indexed: 10/21/2022]
Abstract
BACKGROUND In 2014, recommendations for the nutrition management of phenylalanine hydroxylase deficiency were published as a companion to the concurrently published American College of Medical Genetics and Genomics guideline for the medical treatment of phenylketonuria (PKU). These were developed primarily from a summary of findings from the PKU scientific review conference sponsored by the National Institutes of Health and Agency for Healthcare Research & Quality along with additional systematic literature review. Since that time, the Genetic Metabolic Dietitians International and the Southeast Regional Newborn Screening and Genetics Collaborative have partnered to create a web-based technology platform for the update and development of nutrition management guidelines for inherited metabolic disorders. OBJECTIVE The purpose of this PKU guideline is to establish harmonization in treatment and monitoring, to guide the integration of nutrition therapy in the medical management of PKU, and to improve outcomes (nutritional, cognitive, and developmental) for individuals with PKU in all life stages while reducing associated medical, educational, and social costs. METHODS Six research questions critical to PKU nutrition management were formulated to support guideline development: Review, critical appraisal, and abstraction of peer-reviewed studies and unpublished practice literature, along with expert Delphi survey feedback, nominal group process, and external review from metabolic physicians and dietitians were utilized for development of recommendations relevant to each question. Recommendations address nutrient intake, including updated protein requirements, optimal blood phenylalanine concentrations, nutrition interventions, monitoring parameters specific to life stages, adjunct therapies, and pregnancy and lactation. Recommendations were graded using a rigorous system derived from the Academy of Nutrition and Dietetics. RESULTS AND CONCLUSION These guidelines, updated utilizing a thorough and systematic approach to literature analysis and national consensus process, are now easily accessible to the global community via the newly developed digital platform. For additional details on specific topics, readers are encouraged to review materials on the online portal: https://GMDI.org/.
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Affiliation(s)
- Rani H Singh
- Department of Human Genetics, Emory University School of Medicine, 2165 North Decatur Road, Decatur, Atlanta, GA 30033, USA; Nutrition Health Sciences Program, Graduate Division of Biological and Biomedical Sciences, Emory University School of Arts and Sciences, Atlanta, GA, USA.
| | - Amy C Cunningham
- Hayward Genetics Center, Tulane University School of Medicine, 1430 Tulane Ave, New Orleans, LA 70112, USA.
| | - Shideh Mofidi
- Inherited Metabolic Disease Center, Maria Fareri Childrens Hospital, Westchester Medical Center, New York Medical College, Valhalla, New York, USA.
| | - Teresa D Douglas
- Department of Human Genetics, Emory University School of Medicine, 2165 North Decatur Road, Decatur, Atlanta, GA 30033, USA.
| | - Dianne M Frazier
- Division of Genetics and Metabolism, University of North Carolina School of Medicine, 1100 Manning Drive, Chapel Hill, NC 27599, USA.
| | | | - Laura Jeffers
- Cleveland Clinic, Center for Human Nutrition, 9500 Euclid Ave, Cleveland, OH 44195, USA.
| | - Helen McCune
- Pediatric Genetics and Metabolism, University of Florida, 1600 SW Archer Rd, Gainesville, FL 32607, USA.
| | - Kathryn D Moseley
- Genetics Division, USC/Keck School of Medicine, 1801 Marengo St. Rm. 1G-24, Los Angeles, CA 90033, USA.
| | - Beth Ogata
- University of Washington, Department of Pediatrics, UW-CHDD, Box 357920, Seattle, WA 98195, USA.
| | - Surekha Pendyal
- Division of Genetics and Metabolism, University of North Carolina School of Medicine, 1100 Manning Drive, Chapel Hill, NC 27599, USA.
| | - Jill Skrabal
- Department of Medical Genetics, University of Nebraska Medical Center/Children's Hospital and Medical Center, 981200 Nebraska Medical Center, Omaha, NE. 68198-1200, USA.
| | - Patricia L Splett
- Evaluation Consultant Splett & Associates, LLC, 399 Badger Blvd W., Stanchfield, MN 55080, USA.
| | - Adrya Stembridge
- Department of Human Genetics, Emory University School of Medicine, 2165 North Decatur Road, Decatur, Atlanta, GA 30033, USA.
| | - Ann Wessel
- Division of Genetics and Genomics, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA.
| | - Frances Rohr
- Division of Genetics and Genomics, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA.
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17
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The LATER model of reaction time and decision. Neurosci Biobehav Rev 2016; 64:229-51. [DOI: 10.1016/j.neubiorev.2016.02.018] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 02/03/2016] [Accepted: 02/17/2016] [Indexed: 11/20/2022]
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Cunniffe N, Munby H, Chan S, Saatci D, Edison E, Carpenter RHS, Massey D. Using saccades to diagnose covert hepatic encephalopathy. Metab Brain Dis 2015; 30:821-8. [PMID: 25586511 DOI: 10.1007/s11011-014-9647-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 12/29/2014] [Indexed: 01/18/2023]
Abstract
Covert Hepatic Encephalopathy (CHE), previously known as Minimal Hepatic Encephalopathy, is a subtle cognitive defect found in 30-70 % of cirrhosis patients. It has been linked to poor quality of life, impaired fitness to drive, and increased mortality: treatment is possible. Despite its clinical significance, diagnosis relies on psychometric tests that have proved unsuitable for use in a clinical setting. We investigated whether measurement of saccadic latency distributions might be a viable alternative. We collected data on 35 cirrhosis patients at Addenbrooke's Hospital, Cambridge, with no evidence of clinically overt encephalopathy, and 36 age-matched healthy controls. Performance on standard psychometric tests was evaluated to determine those patients with CHE as defined by the World Congress of Gastroenterology. We then compared visually-evoked saccades between those with CHE and those without, as well as reviewing blood test results and correlating saccadic latencies with biochemical parameters and prognostic scores. Cirrhosis patients have significantly longer median saccadic latencies than healthy controls. Those with CHE had significantly prolonged saccadic latencies when compared with those without CHE. Analysis of a cirrhosis patient's saccades can diagnose CHE with a sensitivity of 75 % and a specificity of 75 %. We concluded that analysis of a cirrhosis patient's saccadic latency distributions is a fast and objective measure that can be used as a diagnostic tool for CHE. This improved early diagnosis could direct avoidance of high-risk activities such as driving, and better inform treatment strategies.
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Affiliation(s)
- Nicholas Cunniffe
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
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19
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Management of adult patients with phenylketonuria: survey results from 24 countries. Eur J Pediatr 2015; 174:119-27. [PMID: 25480112 DOI: 10.1007/s00431-014-2458-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 11/07/2014] [Accepted: 11/12/2014] [Indexed: 10/24/2022]
Abstract
UNLABELLED Phenylketonuria (PKU) is no longer considered merely a pediatric concern; current guidelines recommend life-long treatment. However, information on the adult PKU patient population is scarce. A survey was initiated on behalf of the European PKU Group (EPG) that focused specifically on early-treated adult patients diagnosed by neonatal screening. The online survey was sent via email to 204 healthcare professionals (HCPs) in 33 countries. Eighty-one HCPs from 24 countries responded. The main findings were that the majority of adult patients with PKU in active follow-up are under 30 years of age and are managed in centers that also treat children. Seventy-eight percent of adult PKU patients in follow-up receive treatment, mainly by diet (71 %), with BH4 treatment rarely used in adulthood. Only 26 % of responding HCPs perform routine neurocognitive testing in all their adult patients. There was little consensus regarding target blood phenylalanine (Phe) concentrations, although the majority of respondents reported that their patients achieved blood Phe concentrations below 1200 μmol/l. CONCLUSION This survey highlights the need for blood Phe concentration target recommendations and consensus guidelines, more research into adult PKU patient management, and the need to identify those patients lost to follow-up to ensure PKU is managed for life.
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20
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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.
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21
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Antoniades C, Ettinger U, Gaymard B, Gilchrist I, Kristjánsson A, Kennard C, John Leigh R, Noorani I, Pouget P, Smyrnis N, Tarnowski A, Zee DS, Carpenter RHS. An internationally standardised antisaccade protocol. Vision Res 2013; 84:1-5. [PMID: 23474300 DOI: 10.1016/j.visres.2013.02.007] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Revised: 02/08/2013] [Accepted: 02/09/2013] [Indexed: 11/29/2022]
Abstract
Detailed measurements of saccadic latency--the time taken to make an eye movement to a suddenly-presented visual target--have proved a valuable source of detailed and quantitative information in a wide range of neurological conditions, as well as shedding light on the mechanisms of decision, currently of intense interest to cognitive neuroscientists. However, there is no doubt that more complex oculomotor tasks, and in particular the antisaccade task in which a participant must make a saccade in the opposite direction to the target, are potentially more sensitive indicators of neurological dysfunction, particularly in neurodegenerative conditions. But two obstacles currently hinder their widespread adoption for this purpose. First, that much of the potential information from antisaccade experiments, notably about latency distribution and amplitude, is typically thrown away. Second, that there is no standardised protocol for carrying out antisaccade experiments, so that results from one laboratory cannot easily be compared with those from another. This paper, the outcome of a recent international meeting of oculomotor scientists and clinicians with an unusually wide experience of such measurements, sets out a proposed protocol for clinical antisaccade trials: its adoption will greatly enhance the clinical and scientific benefits of making these kinds of measurements.
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Affiliation(s)
- Chrystalina Antoniades
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK
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22
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Janos AL, Grange DK, Steiner RD, White DA. Processing speed and executive abilities in children with phenylketonuria. Neuropsychology 2012; 26:735-43. [PMID: 22866986 PMCID: PMC3526340 DOI: 10.1037/a0029419] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
OBJECTIVE Phenylketonuria (PKU) is a hereditary metabolic disorder that often results in neuropsychological impairment, even in individuals treated early and continuously. This study was conducted to examine processing speed, variability in processing speed, and the relationship between processing speed variables and executive abilities in children with early and continuously treated PKU. METHOD Participants were 42 children with PKU and 81 typically developing children from 7 to 18 years of age. Children completed 3 computerized reaction time (RT) tasks (simple RT, go/no-go, stimulus-response compatibility) and 7 tasks assessing executive abilities (working memory, inhibitory control, strategic processing). RESULTS Performance of children with PKU was significantly slower and more variable than that of controls across the 3 tasks administered. When age was considered, it was shown that processing speed improved with age to a comparable degree for both groups. Variability in processing speed, however, decreased more with age for the PKU than control group, reflecting the fact that variability in younger, but not older, children with PKU was greater than that of controls. With regard to executive abilities, processing speed and variability contributed to performance on most, but not all, executive tasks; and after controlling for processing speed and variability, executive impairments were still identified in working memory and inhibitory control (not strategic processing). CONCLUSIONS These findings indicate that information processing is slower and less efficient in children with PKU. In addition, processing speed and variability contribute to some, but not all, of the impairments in executive abilities observed in children with PKU.
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Affiliation(s)
- Alicia L. Janos
- Department of Psychology, Washington University in St. Louis
| | - Dorothy K. Grange
- Department of Pediatrics, Division of Genetics and Genomic Medicine, Washington University School of Medicine, St. Louis Children’s Hospital
| | - Robert D. Steiner
- Departments of Pediatrics and Molecular & Medical Genetics, Child Development and Rehabilitation Center/Doernbecher Children’s Hospital, Oregon Health & Science University
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23
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Cunningham A, Bausell H, Brown M, Chapman M, DeFouw K, Ernst S, McClure J, McCune H, O'Steen D, Pender A, Skrabal J, Wessel A, Jurecki E, Shediac R, Prasad S, Gillis J, Cederbaum S. Recommendations for the use of sapropterin in phenylketonuria. Mol Genet Metab 2012; 106:269-76. [PMID: 22575621 DOI: 10.1016/j.ymgme.2012.04.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Revised: 04/05/2012] [Accepted: 04/05/2012] [Indexed: 11/18/2022]
Abstract
Phenylketonuria (PKU) is an inherited disorder of phenylalanine (Phe) metabolism. Until recently, the only treatment for PKU was a Phe-restricted diet. Increasing evidence of suboptimal outcomes in diet-treated individuals, inconsistent PKU management practices, and the recent availability of tetrahydrobiopterin (BH(4)) therapy have fueled the need for new management and treatment recommendations for this metabolic disorder. BH(4), now available as sapropterin dihydrochloride (sapropterin), may offer the potential for improved metabolic control as well as enhanced dietary Phe tolerance in some PKU patients. A group of metabolic dietitians from North America convened in June 2011 to draft recommendations for the use of sapropterin therapy in PKU. Physicians with extensive experience in PKU management were invited at a later date to contribute to the development of these recommendations. Based on extensive clinical experience and current evidence, the present recommendations provide guidance from patient selection and determination of sapropterin response to the long-term management of patients on sapropterin therapy. Target Phe levels, nutritional adequacy, neurocognitive screening and adherence to treatment are addressed to optimize patient outcomes.
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Demirkol M, Giżewska M, Giovannini M, Walter J. Follow up of phenylketonuria patients. Mol Genet Metab 2011; 104 Suppl:S31-9. [PMID: 22018725 DOI: 10.1016/j.ymgme.2011.08.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Revised: 07/31/2011] [Accepted: 08/07/2011] [Indexed: 11/26/2022]
Abstract
In recent years our understanding of the follow up policies for PKU has increased substantially. In particular, we now understand the importance of maintaining control of blood phenylalanine (phe) concentrations life-long to achieve the best long-term neuropsychological outcomes. The concordance with the follow up strategy remains a key challenge for the future, especially with respect to adolescents and young adults. The recent therapies could ease the burden of the dietary phe restriction for PKU patients and their families. The time may be right for revisiting the guidelines for follow up of PKU in order to address a number of important issues related to PKU management: promotion of breastfeeding to complementary feeding up to 2 years of age for prevention of early growth retardation and later overweight development, treatment advancements for metabolic control, blood phe and tyr variability, routine screening measures for nutritional biomarkers, neurocognitive and psychological assessments, bone pathology, understanding the challenges of compliance and transitioning into adulthood as an individual with PKU and addressing unmet needs in this population.
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Affiliation(s)
- M Demirkol
- Div Nutrition and Metabolism, Children's Hospital, Istanbul Medical Faculty, Istanbul University, Istanbul, Turkey.
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