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Brooks DL, Whittaker MN, Qu P, Musunuru K, Ahrens-Nicklas RC, Wang X. Efficient in vivo prime editing corrects the most frequent phenylketonuria variant, associated with high unmet medical need. Am J Hum Genet 2023; 110:2003-2014. [PMID: 37924808 PMCID: PMC10716342 DOI: 10.1016/j.ajhg.2023.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 10/02/2023] [Accepted: 10/06/2023] [Indexed: 11/06/2023] Open
Abstract
The c.1222C>T (p.Arg408Trp) variant in the phenylalanine hydroxylase gene (PAH) is the most frequent cause of phenylketonuria (PKU), the most common inborn error of metabolism. This autosomal-recessive disorder is characterized by accumulation of blood phenylalanine (Phe) to neurotoxic levels. Using real-world data, we observed that despite dietary and medical interventions, most PKU individuals harboring at least one c.1222C>T variant experience chronic, severe Phe elevations and do not comply with Phe monitoring guidelines. Motivated by these findings, we generated an edited c.1222C>T hepatocyte cell line and humanized c.1222C>T mouse models, with which we demonstrated efficient in vitro and in vivo correction of the variant with prime editing. Delivery via adeno-associated viral (AAV) vectors reproducibly achieved complete normalization of blood Phe levels in PKU mice, with up to 52% whole-liver corrective PAH editing. These studies validate a strategy involving prime editing as a potential treatment for a large proportion of individuals with PKU.
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Affiliation(s)
- Dominique L Brooks
- Cardiovascular Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Division of Cardiovascular Medicine, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Madelynn N Whittaker
- Cardiovascular Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Division of Cardiovascular Medicine, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ping Qu
- Cardiovascular Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Division of Cardiovascular Medicine, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kiran Musunuru
- Cardiovascular Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Division of Cardiovascular Medicine, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Rebecca C Ahrens-Nicklas
- Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Metabolic Disease Program, Division of Human Genetics, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Xiao Wang
- Cardiovascular Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Division of Cardiovascular Medicine, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
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De Giorgi A, Nardecchia F, Romani C, Leuzzi V. Metabolic control and clinical outcome in adolescents with phenylketonuria. Mol Genet Metab 2023; 140:107684. [PMID: 37672857 DOI: 10.1016/j.ymgme.2023.107684] [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: 06/30/2023] [Revised: 08/11/2023] [Accepted: 08/11/2023] [Indexed: 09/08/2023]
Abstract
The main neurological, cognitive, and behavioural consequences of phenylketonuria have been eradicated thanks to new-born screening and Phe-restricted diet therapy. However, the effects of high phenylalanine levels during adolescence and adulthood on neurocognitive functions remain a concern. This systematic review aimed at collecting clinical data suggesting the safest metabolic target for early treated PKU during the second decade of life. Twenty studies met the inclusion criteria for full-text review. Relevant studies included papers that (a) examined the relationship between metabolic control and neurocognitive functions during adolescence or (b) investigated the impact of metabolic control in adolescence on adult outcomes. Most studies showed a positive correlation between metabolic control during adolescence and neurocognitive outcomes across ages. This was true both for IQ and executive functions, although data on executive functions were less clear, and it remains to be established whether they are more vulnerable to Phe than IQ. Taken together present evidence confirm brain vulnerability to Phe during adolescence and suggests that low average Phe levels and low Phe fluctuations should be maintained throughout life. While results are fully compatible with current European recommendations, clinical and methodological limitations coupled with remarkable interindividual variability prevented a clear identification of a safe threshold for Phe blood levels during adolescence.
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Affiliation(s)
- Agnese De Giorgi
- Unit of Child Neurology and Psychiatry, Department of Human Neuroscience, Sapienza University of Rome, Rome, Italy
| | - Francesca Nardecchia
- Unit of Child Neurology and Psychiatry, Department of Human Neuroscience, Sapienza University of Rome, Rome, Italy
| | - Cristina Romani
- School of Life and Health Sciences, Aston University, Birmingham, UK
| | - Vincenzo Leuzzi
- Unit of Child Neurology and Psychiatry, Department of Human Neuroscience, Sapienza University of Rome, Rome, Italy.
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Yılmaz BK, Baykan A, Kardaş F, Kendirci M. Evaluation of the effect of obesity, dietary glycemic index and metabolic profiles on the cardiovascular risk in children with classical phenylketonuria. Mol Genet Metab 2023; 140:107677. [PMID: 37544048 DOI: 10.1016/j.ymgme.2023.107677] [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: 04/26/2023] [Revised: 07/30/2023] [Accepted: 08/01/2023] [Indexed: 08/08/2023]
Abstract
OBJECTIVES To compare the glycemic index(GI),obesity,echocardiographic,and arterial stiffness measurements with the healthy control group to evaluate the cardiovascular risk of pediatric classical phenylketonuria(PKU). METHODS The study was a prospective observational,involving 104 pediatric volunteers between 2019 and 2020.Two groups were formed:the PKU patient group and the healthy control group.These two groups were further divided into three subgroups:obese,overweight,and normal weight.The patients' anthropometric measurements,body fat analysis,biochemical analysis, GI and glycemic load(GL),arterial stiffness measurements,and echocardiographic findings were recorded. RESULTS The PKU patient group's glucose,total cholesterol,LDL,and HDL values were significantly lower than the healthy control group(p = 0.010 for glucose and p = 0.001 for total cholesterol,LDL and HDL).Triglyceride levels were higher in the PKU patient group than in the healthy controls(109.6 vs. 76.7 mg/dl,p = 0.001). GI and GL were significantly lower in the PKU patient group than in the healthy control group(GI 453 vs. 392.9,p = 0.017 and GL 101.1 vs. 85.5,p = 0.036).Left ventricular mass(LVM)-z-score and LVM index were significantly higher in the PKU group than in the healthy control group(LVM z-score 0.9 vs. 0.5,p = 0.014 and LVM index 38.9 vs. 32.7 g/m2.7,p = 0.001). A moderately statistically significant positive correlation was found between the mean phenylalanine(phe) value and pulse wave velocity(PWV) among the PKU patient groups(R: 0.477,p < 0.001).A moderately statistically significant positive correlation was also found between waist circumference and PWV in the PKU patient group(R:0.541, p < 0.001). CONCLUSIONS Our study found that close follow-up of phe levels and PWV is more critical than obesity, GI, and GL in the cardiovascular evaluation of classical PKU patients.A large number of multicenter pediatric studies are needed in this area.
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Affiliation(s)
- Banu Kadıoğlu Yılmaz
- Department of Pediatric Metabolism, Konya City Hospital, University of Health Sciences, Konya, Turkey.
| | - Ali Baykan
- Department of Pediatric Cardiology, Erciyes University Medical Faculty, Kayseri, Turkey.
| | - Fatih Kardaş
- Department of Pediatric Metabolism, Erciyes University Medical Faculty, Kayseri, Turkey.
| | - Mustafa Kendirci
- Department of Pediatric Endocrinology and Metabolism, Bağcılar Medipol Mega University Hospital, İstanbul, Turkey
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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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Rocha JC, Ahring KK, Bausell H, Bilder DA, Harding CO, Inwood A, Longo N, Muntau AC, Pessoa ALS, Rohr F, Sivri S, Hermida Á. Expert Consensus on the Long-Term Effectiveness of Medical Nutrition Therapy and Its Impact on the Outcomes of Adults with Phenylketonuria. Nutrients 2023; 15:3940. [PMID: 37764724 PMCID: PMC10536918 DOI: 10.3390/nu15183940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 08/28/2023] [Accepted: 09/06/2023] [Indexed: 09/29/2023] Open
Abstract
Many adults with phenylketonuria (PKU) rely on medical nutrition therapy (MNT; low phenylalanine (Phe) diet with protein substitutes/medical foods) to maintain blood Phe concentrations within recommended ranges and prevent PKU-associated comorbidities. Despite disease detection through newborn screening and introduction of MNT as early as birth, adherence to MNT often deteriorates from childhood onwards, complicating the assessment of its effectiveness in the long term. Via a modified Delphi process, consensus (≥70% agreement) was sought on 19 statements among an international, multidisciplinary 13-member expert panel. After three iterative voting rounds, the panel achieved consensus on 17 statements related to the limitations of the long-term effectiveness of MNT (7), the burden of long-term reliance on MNT (4), and its potential long-term detrimental health effects (6). According to the expert panel, the effectiveness of MNT is limited in the long term, is associated with a high treatment burden, and demonstrates that adults with PKU are often unable to achieve metabolic control through dietary management alone, creating an unmet need in the adult PKU population.
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Affiliation(s)
- Júlio César Rocha
- NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Campo Mártires da Pátria 130, 1169-056 Lisboa, Portugal
- Reference Centre of Inherited Metabolic Diseases, Centro Hospitalar Universitário de Lisboa Central, Rua Jacinta Marto, 1169-045 Lisboa, Portugal
- CINTESIS@RISE, Nutrition and Metabolism, NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Campo Mártires da Pátria 130, 1169-056 Lisboa, Portugal
| | - Kirsten K. Ahring
- Departments of Paediatrics and Clinical Genetics, PKU Clinic, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Heather Bausell
- Division of Genetics, Genomics, and Metabolism, Ann & Robert H Lurie Children’s Hospital of Chicago, 225 E. Chicago Ave., Chicago, IL 60611, USA
| | - Deborah A. Bilder
- Department of Psychiatry, Division of Child & Adolescent Psychiatry, University of Utah Huntsman Mental Health Institute, 501 Chipeta Way, Salt Lake City, UT 84108, USA
| | - Cary O. Harding
- Department of Molecular and Medical Genetics, Oregon Health & Science University, 3222 SW Research Drive, Portland, OR 97239, USA
| | - Anita Inwood
- Queensland Lifespan Metabolic Medicine Service, Queensland Children’s Hospital, 501 Stanley St., South Brisbane, QLD 4101, Australia
- School of Nursing and Social Work, The University of Queensland, Chamberlain Building, St. Lucia, QLD 4072, Australia
| | - Nicola Longo
- Department of Pediatrics, Division of Medical Genetics, University of Utah School of Medicine, 295 Chipeta Way, Salt Lake City, UT 84108, USA
| | - Ania C. Muntau
- Department of Pediatrics, University Children’s Hospital, University Medical Centre Hamburg-Eppendorf, Martinistraße 52, 20246 Hamburg, Germany
| | - André L. Santos Pessoa
- Albert Sabin Children’s Hospital, R. Tertuliano Sales, 544—Vila União, Fortaleza 60410-794, CE, Brazil
- Av. Dr. Silas Munguba, 1700—Itaperi, State University of Ceará (UECE), Fortaleza 60714-903, CE, Brazil
| | | | - Serap Sivri
- Division of Pediatric Metabolism, Department of Pediatrics, Faculty of Medicine, Hacettepe University, Gevher Nesibe Cd., 06230 Ankara, Turkey
| | - Álvaro Hermida
- Diagnosis and Treatment of Congenital Metabolic Diseases Unit (UDyTEMC), Department of Pediatrics, Faculty of Medicine, Clinical University Hospital of Santiago de Compostela, University of Santiago de Compostela, CIBERER, MetabERN, Institute of Clinical Research of Santiago de Compostela (IDIS), Rúa de San Francisco s/n, 15706 Santiago de Compostela, Spain
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Adams AD, Fiesco-Roa MÓ, Wong L, Jenkins GP, Malinowski J, Demarest OM, Rothberg PG, Hobert JA. Phenylalanine hydroxylase deficiency treatment and management: A systematic evidence review of the American College of Medical Genetics and Genomics (ACMG). Genet Med 2023; 25:100358. [PMID: 37470789 DOI: 10.1016/j.gim.2022.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 12/08/2022] [Accepted: 12/08/2022] [Indexed: 07/21/2023] Open
Abstract
PURPOSE Elevated serum phenylalanine (Phe) levels due to biallelic pathogenic variants in phenylalanine hydroxylase (PAH) may cause neurodevelopmental disorders or birth defects from maternal phenylketonuria. New Phe reduction treatments have been approved in the last decade, but uncertainty on the optimal lifespan goal Phe levels for patients with PAH deficiency remains. METHODS We searched Medline and Embase for evidence of treatment concerning PAH deficiency up to September 28, 2021. Risk of bias was evaluated based on study design. Random-effects meta-analyses were performed to compare IQ, gestational outcomes, and offspring outcomes based on Phe ≤ 360 μmol/L vs > 360 μmol/L and reported as odds ratio and 95% CI. Remaining results were narratively synthesized. RESULTS A total of 350 studies were included. Risk of bias was moderate. Lower Phe was consistently associated with better outcomes. Achieving Phe ≤ 360 μmol/L before conception substantially lowered the risk of negative effect to offspring in pregnant individuals (odds ratio = 0.07, 95% CI = 0.04-0.14; P < .0001). Adverse events due to pharmacologic treatment were common, but medication reduced Phe levels, enabling dietary liberalization. CONCLUSIONS Reduction of Phe levels to ≤360 μmol/L through diet or medication represents effective interventions to treat PAH deficiency.
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Affiliation(s)
- April D Adams
- Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, TX; Division of Maternal-Fetal Medicine, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Moisés Ó Fiesco-Roa
- Programa de Maestría y Doctorado en Ciencias Médicas, Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico; Laboratorio de Citogenética, Instituto Nacional de Pediatría, Mexico City, Mexico
| | | | | | | | | | - Paul G Rothberg
- Department of Pathology & Laboratory Medicine, University of Rochester Medical Center, Rochester, NY
| | - Judith A Hobert
- University of Utah School of Medicine, Salt Lake City, UT; ARUP Laboratories, Salt Lake City, UT
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Schoen MS, Boland KM, Christ SE, Cui X, Ramakrishnan U, Ziegler TR, Alvarez JA, Singh RH. Total choline intake and working memory performance in adults with phenylketonuria. Orphanet J Rare Dis 2023; 18:222. [PMID: 37516884 PMCID: PMC10386684 DOI: 10.1186/s13023-023-02842-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 07/21/2023] [Indexed: 07/31/2023] Open
Abstract
BACKGROUND Despite early diagnosis and compliance with phenylalanine (Phe)-restricted diets, many individuals with phenylketonuria (PKU) still exhibit neurological changes and experience deficits in working memory and other executive functions. Suboptimal choline intake may contribute to these impairments, but this relationship has not been previously investigated in PKU. The objective of this study was to determine if choline intake is correlated with working memory performance, and if this relationship is modified by diagnosis and metabolic control. METHODS This was a cross-sectional study that included 40 adults with PKU and 40 demographically matched healthy adults. Web-based neurocognitive tests were used to assess working memory performance and 3-day dietary records were collected to evaluate nutrient intake. Recent and historical blood Phe concentrations were collected as measures of metabolic control. RESULTS Working memory performance was 0.32 z-scores (95% CI 0.06, 0.58) lower, on average, in participants with PKU compared to participants without PKU, and this difference was not modified by total choline intake (F[1,75] = 0.85, p = 0.36). However, in a subgroup with complete historical blood Phe data, increased total choline intake was related to improved working memory outcomes among participants with well controlled PKU (Phe = 360 µmol/L) after adjusting for intellectual ability and mid-childhood Phe concentrations (average change in working memory per 100 mg change in choline = 0.11; 95% CI 0.02, 0.20; p = 0.02). There also was a trend, albeit nonsignificant (p = 0.10), for this association to be attenuated with increased Phe concentrations. CONCLUSIONS Clinical monitoring of choline intake is essential for all individuals with PKU but may have important implications for working memory functioning among patients with good metabolic control. Results from this study should be confirmed in a larger controlled trial in people living with PKU.
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Affiliation(s)
- Meriah S Schoen
- Department of Human Genetics, Emory University School of Medicine, 101 Woodruff Circle, Suite 7130, Atlanta, GA, 30322, USA.
| | - Kelly M Boland
- Department of Psychological Sciences, University of Missouri, Columbia, MO, USA
| | - Shawn E Christ
- Department of Psychological Sciences, University of Missouri, Columbia, MO, USA
| | - Xiangqin Cui
- Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, GA, USA
| | - Usha Ramakrishnan
- Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, GA, USA
| | - Thomas R Ziegler
- Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Jessica A Alvarez
- Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Rani H Singh
- Department of Human Genetics, Emory University School of Medicine, 101 Woodruff Circle, Suite 7130, Atlanta, GA, 30322, USA
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Rovelli V, Longo N. Phenylketonuria and the brain. Mol Genet Metab 2023; 139:107583. [PMID: 37105048 DOI: 10.1016/j.ymgme.2023.107583] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 04/14/2023] [Accepted: 04/14/2023] [Indexed: 04/29/2023]
Abstract
Classic phenylketonuria (PKU) is caused by defective activity of phenylalanine hydroxylase (PAH), the enzyme that coverts phenylalanine (Phe) to tyrosine. Toxic accumulation of phenylalanine and its metabolites, left untreated, affects brain development and function depending on the timing of exposure to elevated levels. The specific mechanisms of Phe-induced brain damage are not completely understood, but they correlate to phenylalanine levels and on the stage of brain growth. During fetal life, high levels of phenylalanine such as those seen in maternal PKU can result in microcephaly, neuronal loss and corpus callosum hypoplasia. Elevated phenylalanine levels during the first few years of life can cause acquired microcephaly, severe cognitive impairment and epilepsy, likely due to the impairment of synaptogenesis. During late childhood, elevated phenylalanine can cause alterations in neurological functioning, leading to ADHD, speech delay and mild IQ reduction. In adolescents and adults, executive function and mood are affected, with some of the abnormalities reversed by better control of phenylalanine levels. Altered brain myelination can be present at this stage. In this article, we review the current knowledge about the consequences of high phenylalanine levels in PKU patients and animal models through different stages of brain development and its effect on cognitive, behavioural and neuropsychological function.
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Affiliation(s)
- Valentina Rovelli
- Clinical Department of Pediatrics, University of Milan, ASST Santi Paolo e Carlo, San Paolo Hospital, Milan, Italy.
| | - Nicola Longo
- Division of Medical Genetics, Department of Pediatrics, University of Utah, Salt Lake City, UT, USA
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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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Costa-Lathan C, Vazquez-Agra N, Marques-Afonso AT, Cruces-Sande A, Martinez-Olmos MA, Araujo-Vilar D, Hermida-Ameijeiras A. The role of phenylalanine levels in the neuropsychological and neuroanatomical status of adult patients with phenylketonuria: The impact of fluctuations. J Investig Med 2023; 71:149-158. [PMID: 36647337 DOI: 10.1177/10815589221143485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
We aimed to evaluate the role of plasma phenylalanine (Phe) levels and its fluctuations in some neurocognitive domains and brain magnetic resonance imaging (MRI) findings in adult patients with phenylketonuria (PKU). It was an observational study that included patients older than 18 years with early-treated classical PKU. Plasma Phe levels were measured every other month throughout 2 years and predictor variables were the mean, maximum (max), minimum (min), range (min-max), and plasma Phe levels at the time of cognitive testing. Patients were evaluated for executive function, processing speed, visual attention, and fluid cognitive abilities using the Trail Making Test (TMT) and for the presence of brain MRI abnormalities. In all, 22 patients with a mean age of 34 years were included, of which 18 (81%) were women. Patients with higher range and maximum Phe levels had a poorer time-based performance on TMT form A and form B. Patients with brain MRI abnormalities had higher range, maximum, and mean Phe levels. Range of Phe levels showed a good performance for MRI abnormalities (area under the curve (AUC): 0.881, standard error (SE): 0.095, 95% CI: 0.695-0.999, p = 0.044) and for the poorest time-based performances on TMT form A (AUC: 0.822, SE: 0.092, 95% CI: 0.641-0.999, p = 0.024) and B (AUC: 0.816, SE: 0.094, 95% CI: 0.632-0.999, p = 0.021). Greater Phe variability may have a negative impact on some neurocognitive domains and could be related to the severity of brain structural damage in adult patients with PKU.
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Affiliation(s)
| | - Nestor Vazquez-Agra
- Department of Internal Medicine, University Hospital of Santiago de Compostela, A Coruña, Spain
| | | | - Anton Cruces-Sande
- Laboratory of Neurochemistry, Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Santiago de Compostela, A Coruña, Spain
| | - Miguel-Angel Martinez-Olmos
- Division of Endocrinology and Nutrition, University Hospital of Santiago de Compostela, A Coruña, Spain.,CIBER Pathophysiology of Obesity and Nutrition (CIBERobn), Carlos III Health Institute, Madrid, Spain
| | - David Araujo-Vilar
- Division of Endocrinology and Nutrition, University Hospital of Santiago de Compostela, A Coruña, Spain.,UETeM-Molecular Pathology Group, Department of Medicine, IDIS-CIMUS, University of Santiago de Compostela, A Coruña, Spain
| | - Alvaro Hermida-Ameijeiras
- Department of Internal Medicine, University Hospital of Santiago de Compostela, A Coruña, Spain.,UETeM-Molecular Pathology Group, Department of Medicine, IDIS-CIMUS, University of Santiago de Compostela, A Coruña, Spain
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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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12
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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: 0] [Impact Index Per Article: 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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13
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Lotz-Havla AS, Katzdobler S, Nuscher B, Weiß K, Levin J, Havla J, Maier EM. Serum glial fibrillary acidic protein and neurofilament light chain in patients with early treated phenylketonuria. Front Neurol 2022; 13:1011470. [PMID: 36247773 PMCID: PMC9559705 DOI: 10.3389/fneur.2022.1011470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 09/12/2022] [Indexed: 12/01/2022] Open
Abstract
To pave the way for healthy aging in early treated phenylketonuria (ETPKU) patients, a better understanding of the neurological course in this population is needed, requiring easy accessible biomarkers to monitor neurological disease progression in large cohorts. The objective of this pilot study was to investigate the potential of glial fibrillary acidic protein (GFAP) and neurofilament light chain (NfL) as blood biomarkers to indicate changes of the central nervous system in ETPKU. In this single-center cross-sectional study, GFAP and NfL concentrations in serum were quantified using the Simoa® multiplex technology in 56 ETPKU patients aged 6–36 years and 16 age matched healthy controls. Correlation analysis and hierarchical linear regression analysis were performed to investigate an association with disease-related biochemical parameters and retinal layers assessed by optical coherence tomography. ETPKU patients did not show significantly higher GFAP concentrations (mean 73 pg/ml) compared to healthy controls (mean 60 pg/ml, p = 0.140). However, individual pediatric and adult ETPKU patients had GFAP concentrations above the healthy control range. In addition, there was a significant association of GFAP concentrations with current plasma tyrosine concentrations (r = −0.482, p = 0.036), a biochemical marker in phenylketonuria, and the retinal inner nuclear layer volume (r = 0.451, p = 0.04). There was no evidence of NfL alterations in our ETPKU cohort. These pilot results encourage multicenter longitudinal studies to further investigate serum GFAP as a complementary tool to better understand and monitor neurological disease progression in ETPKU. Follow-up investigations on aging ETPKU patients are required to elucidate the potential of serum NfL as biomarker.
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Affiliation(s)
- Amelie S. Lotz-Havla
- Department of Pediatrics, Dr. von Hauner Children's Hospital, University Hospital, LMU Munich, Munich, Germany
| | - Sabrina Katzdobler
- Department of Neurology, University Hospital, LMU Munich, Munich, Germany
| | - Brigitte Nuscher
- Department of Neurology, University Hospital, LMU Munich, Munich, Germany
| | - Katharina Weiß
- Department of Pediatrics, Dr. von Hauner Children's Hospital, University Hospital, LMU Munich, Munich, Germany
| | - Johannes Levin
- Department of Neurology, University Hospital, LMU Munich, Munich, Germany
- German Center for Neurodegenerative Diseases, site Munich, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Joachim Havla
- Institute of Clinical Neuroimmunology, University Hospital, LMU Munich, Munich, Germany
- Data Integration for Future Medicine (DIFUTURE) Consortium, LMU Munich, Munich, Germany
- *Correspondence: Joachim Havla
| | - Esther M. Maier
- Department of Pediatrics, Dr. von Hauner Children's Hospital, University Hospital, LMU Munich, Munich, Germany
- Esther M. Maier
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14
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Burton BK, Hermida Á, Bélanger-Quintana A, Bell H, Bjoraker KJ, Christ SE, Grant ML, Harding CO, Huijbregts SCJ, Longo N, McNutt MC, Nguyen-Driver MD, Santos Pessoa AL, Rocha JC, Sacharow S, Sanchez-Valle A, Sivri HS, Vockley J, Walterfang M, Whittle S, Muntau AC. Management of early treated adolescents and young adults with phenylketonuria: Development of international consensus recommendations using a modified Delphi approach. Mol Genet Metab 2022; 137:114-126. [PMID: 36027720 DOI: 10.1016/j.ymgme.2022.07.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 06/16/2022] [Accepted: 07/23/2022] [Indexed: 11/20/2022]
Abstract
BACKGROUND Early treated patients with phenylketonuria (PKU) often become lost to follow-up from adolescence onwards due to the historical focus of PKU care on the pediatric population and lack of programs facilitating the transition to adulthood. As a result, evidence on the management of adolescents and young adults with PKU is limited. METHODS Two meetings were held with a multidisciplinary international panel of 25 experts in PKU and comorbidities frequently experienced by patients with PKU. Based on the outcomes of the first meeting, a set of statements were developed. During the second meeting, these statements were voted on for consensus generation (≥70% agreement), using a modified Delphi approach. RESULTS A total of 37 consensus recommendations were developed across five areas that were deemed important in the management of adolescents and young adults with PKU: (1) general physical health, (2) mental health and neurocognitive functioning, (3) blood Phe target range, (4) PKU-specific challenges, and (5) transition to adult care. The consensus recommendations reflect the personal opinions and experiences from the participating experts supported with evidence when available. Overall, clinicians managing adolescents and young adults with PKU should be aware of the wide variety of PKU-associated comorbidities, initiating screening at an early age. In addition, management of adolescents/young adults should be a joint effort between the patient, clinical center, and parents/caregivers supporting adolescents with gradually gaining independent control of their disease during the transition to adulthood. CONCLUSIONS A multidisciplinary international group of experts used a modified Delphi approach to develop a set of consensus recommendations with the aim of providing guidance and offering tools to clinics to aid with supporting adolescents and young adults with PKU.
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Affiliation(s)
- Barbara K Burton
- Ann and Robert H. Lurie Children's Hospital and Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
| | - Álvaro Hermida
- Clinical University Hospital of Santiago de Compostela, University of Santiago de Compostela, CIBERER, MetabERN, Institute of Clinical Research of Santiago de Compostela (IDIS), Santiago de Compostela, Spain
| | | | - Heather Bell
- Fred A. Litwin Family Centre in Genetic Medicine, University Health Network and Mount Sinai Hospital, Toronto, ON, Canada
| | | | - Shawn E Christ
- Department of Psychological Sciences, University of Missouri, Columbia, MO, USA
| | - Mitzie L Grant
- Department of Psychiatry, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Cary O Harding
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR, USA
| | | | - Nicola Longo
- Division of Medical Genetics, Department of Pediatrics, University of Utah, Salt Lake City, UT, USA
| | - Markey C McNutt
- McDermott Center for Human Growth and Development, UT Southwestern Medical Center, Dallas, TX, USA
| | - Mina D Nguyen-Driver
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR, USA
| | - André L Santos Pessoa
- Pediatric Neurology Service, Albert Sabin Children's Hospital, University of Ceará State, Fortaleza, Ceará, Brazil
| | - Júlio César Rocha
- Nutrition and Metabolism, NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Portugal; Neuropsychiatry Unit, Royal Melbourne Hospital, Melbourne, VIC, Australia; Melbourne Neuropsychiatry Centre, University of Melbourne, Melbourne, VIC, Australia
| | - Stephanie Sacharow
- CINTESIS-Center for Health Technology and Services Research, NOVA Medical School, Lisboa, Portugal; Florey Institute of Neuroscience and Mental Health, Melbourne, VIC, Australia
| | - Amarilis Sanchez-Valle
- Reference Centre of Inherited Metabolic Diseases, Centro Hospitalar Universitário de Lisboa Central, Lisboa, Portugal
| | - H Serap Sivri
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, USA
| | - Jerry Vockley
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Mark Walterfang
- Department of Pediatrics, Morsani College of Medicine, University of South Florida, Tampa, FL, USA; Melbourne Neuropsychiatry Centre, Department of Psychiatry, University of Melbourne, Melbourne, VIC, Australia; University Children's Hospital, University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | - Sarah Whittle
- Hacettepe University, Faculty of Medicine, Department of Pediatrics, Section of Pediatric Metabolism, Ankara, Turkey
| | - Ania C Muntau
- Department of Pediatrics, University of Pittsburgh Medical Center Children's Hospital of Pittsburgh, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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15
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Abgottspon S, Muri R, Christ SE, Hochuli M, Radojewski P, Trepp R, Everts R. Neural correlates of working memory and its association with metabolic parameters in early-treated adults with phenylketonuria. Neuroimage Clin 2022; 34:102974. [PMID: 35248901 PMCID: PMC8897706 DOI: 10.1016/j.nicl.2022.102974] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 02/22/2022] [Accepted: 02/25/2022] [Indexed: 11/18/2022]
Abstract
Working memory (WM) accuracy was significantly reduced in the PKU group. Reaction time did not differ between individuals with PKU and controls. No group differences were found with regard to neural activation. Neural activation was related to concurrent metabolic parameters. Results suggest interrelations between neural, cognitive, and metabolic parameters.
Background Phenylketonuria (PKU) is an inborn error of metabolism affecting the conversion of phenylalanine (Phe) into tyrosine. Previous research has found cognitive and functional brain alterations in individuals with PKU even if treated early. However, little is known about working memory processing and its association with task performance and metabolic parameters. The aim of the present study was to examine neural correlates of working memory and its association with metabolic parameters in early-treated adults with PKU. Methods This cross-sectional study included 20 early-treated adults with PKU (mean age: 31.4 years ± 9.0) and 40 healthy controls with comparable age, sex, and education (mean age: 29.8 years ± 8.2). All participants underwent functional magnetic resonance imaging (fMRI) of working memory to evaluate the fronto-parietal working memory network. Fasting blood samples were collected from the individuals with PKU to acquire a concurrent plasma amino acid profile, and retrospective Phe concentrations were obtained to estimate an index of dietary control. Results On a cognitive level, early-treated adults with PKU displayed significantly lower accuracy but comparable reaction time in the working memory task compared to the control group. Whole-brain analyses did not reveal differences in working memory-related neural activation between the groups. Exploratory region-of-interest (ROI) analyses indicated reduced neural activation in the left and right middle frontal gyri and the right superior frontal gyrus in the PKU group compared to the control group. However, none of the ROI analyses survived correction for multiple comparisons. Neural activation was related to concurrent Phe, tyrosine, and tryptophan concentrations but not to retrospective Phe concentrations. Conclusion In early-treated adults with PKU, cognitive performance and neural activation are slightly altered, a result that is partly related to metabolic parameters. This study offers a rare insight into the complex interplay between metabolic parameters, neural activation, and cognitive performance in a sample of individuals with PKU.
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Affiliation(s)
- Stephanie Abgottspon
- Department of Diabetes, Endocrinology, Nutritional Medicine and Metabolism, Inselspital, Bern University Hospital and University of Bern, Switzerland; Graduate School for Health Sciences, University of Bern, Switzerland; Translational Imaging Center (TIC), Swiss Institute for Translational and Entrepreneurial Medicine, Bern, Switzerland
| | - Raphaela Muri
- Department of Diabetes, Endocrinology, Nutritional Medicine and Metabolism, Inselspital, Bern University Hospital and University of Bern, Switzerland; Graduate School for Health Sciences, University of Bern, Switzerland; Support Center for Advanced Neuroimaging (SCAN), Institute of Diagnostic and Interventional Neuroradiology, Inselspital, Bern University Hospital and University of Bern, Switzerland; Translational Imaging Center (TIC), Swiss Institute for Translational and Entrepreneurial Medicine, Bern, Switzerland
| | - Shawn E Christ
- Department of Psychological Sciences, University of Missouri, Columbia, MO, USA
| | - Michel Hochuli
- Department of Diabetes, Endocrinology, Nutritional Medicine and Metabolism, Inselspital, Bern University Hospital and University of Bern, Switzerland
| | - Piotr Radojewski
- Support Center for Advanced Neuroimaging (SCAN), Institute of Diagnostic and Interventional Neuroradiology, Inselspital, Bern University Hospital and University of Bern, Switzerland; Translational Imaging Center (TIC), Swiss Institute for Translational and Entrepreneurial Medicine, Bern, Switzerland
| | - Roman Trepp
- Department of Diabetes, Endocrinology, Nutritional Medicine and Metabolism, Inselspital, Bern University Hospital and University of Bern, Switzerland; Translational Imaging Center (TIC), Swiss Institute for Translational and Entrepreneurial Medicine, Bern, Switzerland
| | - Regula Everts
- Department of Diabetes, Endocrinology, Nutritional Medicine and Metabolism, Inselspital, Bern University Hospital and University of Bern, Switzerland; Division of Neuropaediatrics, Development and Rehabilitation, Inselspital Bern, Children's University Hospital, Bern, Switzerland; Translational Imaging Center (TIC), Swiss Institute for Translational and Entrepreneurial Medicine, Bern, Switzerland.
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16
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Bik-Multanowski M, Didycz B, Bik-Multanowska K. Management precautions for risk of obesity are necessary among infants with PKU carrying the rs113883650 variant of the LAT1 gene: A cross-sectional study. PLoS One 2022; 17:e0264084. [PMID: 35176108 PMCID: PMC8853486 DOI: 10.1371/journal.pone.0264084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Accepted: 02/03/2022] [Indexed: 11/26/2022] Open
Abstract
Patients with phenylketonuria (PKU), an inborn error of phenylalanine metabolism, require consistent treatment to avoid the brain toxicity caused by hyperphenylalaninemia. The treatment consists of life-long use of a low-phenylalanine diet, which aims at decreasing hyperphenylalaninemia and maintaining blood phenylalanine concentration in a safe range. Problems with balancing diet can result in suboptimal treatment outcomes; however, recent findings suggest that genetic alteration of the transport of phenylalanine might result in an additional health burden. We assessed the effect of a common variant (rs113883650) of the LAT1(SLC7A5) gene, which encodes the main transmembrane phenylalanine transporter, on the development of overweight in 54 infants with PKU who received standard therapy and adhered well to therapeutic prescriptions, and in 55 infants with a milder disease form—the so-called mild hyperphenylalaninemia (MHP), which does not require treatment. We found that infants with PKU—carriers of the rs113883650 variant had significantly higher Body Mass Index (BMI) at 1 year compared to PKU infants without the variant (mean BMI Z-Score of +1.15 SD vs -0.15 SD, respectively; t(52) = 5.25, p = 0.00005). Conversely, no significant BMI differences were detected in the subgroups of infants with MHP (t(53) = 1.15, p = 0.25). Additionally, high BMI in infants with PKU—carriers of the rs113883650 variant positively correlated with high variability of their blood phenylalanine levels (r(52) = 0.42, p = 0.002). It should be noted that this is an observational study, which does not determine causation. Nevertheless, our findings show that the rs113883650 variant of the LAT1 gene may be a risk factor for overweight in properly treated infants with PKU. Management precautions should be taken to prevent the development of overweight and obesity.
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Affiliation(s)
- Miroslaw Bik-Multanowski
- Department of Medical Genetics, Jagiellonian University Medical College, Krakow, Poland
- * E-mail:
| | - Bozena Didycz
- Department of Medical Genetics, Jagiellonian University Medical College, Krakow, Poland
| | - Kinga Bik-Multanowska
- Department of Medical Genetics, Jagiellonian University Medical College, Krakow, Poland
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17
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Lotz-Havla AS, Weiß K, Schiergens K, Regenauer-Vandewiele S, Parhofer KG, Christmann T, Böhm L, Havla J, Maier EM. Optical Coherence Tomography to Assess Neurodegeneration in Phenylalanine Hydroxylase Deficiency. Front Neurol 2021; 12:780624. [PMID: 34956063 PMCID: PMC8703042 DOI: 10.3389/fneur.2021.780624] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 11/02/2021] [Indexed: 11/13/2022] Open
Abstract
In phenylalanine hydroxylase (PAH) deficiency, an easily feasible method to access the progression of neurodegeneration is warranted to contribute to current discussions on treatment indications and targets. The objective of the present study was to investigate whether optical coherence tomography (OCT) measures as markers of neurodegeneration differ between patients with PAH deficiency and healthy controls (HCs) according to phenotype and metabolic control. In this single-center cross-sectional study, 92 patients with different phenotypes of PAH deficiency [PAH deficiency not requiring treatment, early treated phenylketonuria (ETPKU), and late-diagnosed phenylketonuria (PKU)] compared with 76 HCs were examined using spectral-domain OCT. Indices of phenylalanine elevation and variability were correlated with OCT parameters. Late-diagnosed PKU patients showed reduced peripapillary retinal nerve fiber layer (pRNFL) thickness and combined ganglion cell and inner plexiform layer (GCIPL) volume. Adult ETPKU patients were found to have lower GCIPL volume (p = 0.016), which correlated with the indices of phenylalanine control. In pediatric ETPKU patients with poor metabolic control, pRNFL was significantly reduced (p = 0.004). Patients with PAH deficiency not requiring treatment did not exhibit retinal degeneration. Inner nuclear layer (INL) was significantly increased in the pediatric ETPKU patients, driven by those with current poor metabolic control (p = 0.006). Our data provide evidence of retinal neuroaxonal degeneration and INL swelling, depending on the phenotype, current age, and metabolic control. These findings suggest that OCT is suitable to investigate neurodegeneration in PKU and we propose OCT as a sensitive, reliable, safe, low-burden, and low-cost examination for future multicenter studies.
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Affiliation(s)
- Amelie S Lotz-Havla
- Dr. von Hauner Children's Hospital, LMU University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Katharina Weiß
- Dr. von Hauner Children's Hospital, LMU University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Katharina Schiergens
- Dr. von Hauner Children's Hospital, LMU University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany
| | | | - Klaus G Parhofer
- Medical Department IV - Grosshadern, LMU University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Tara Christmann
- Institute of Clinical Neuroimmunology, LMU University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Luise Böhm
- Institute of Clinical Neuroimmunology, LMU University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Joachim Havla
- Institute of Clinical Neuroimmunology, LMU University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany.,Data Integration for Future Medicine (DIFUTURE) Consortium, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Esther M Maier
- Dr. von Hauner Children's Hospital, LMU University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany
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18
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Burlina A, Biasucci G, Carbone MT, Cazzorla C, Paci S, Pochiero F, Spada M, Tummolo A, Zuvadelli J, Leuzzi V. Italian national consensus statement on management and pharmacological treatment of phenylketonuria. Orphanet J Rare Dis 2021; 16:476. [PMID: 34784942 PMCID: PMC8594187 DOI: 10.1186/s13023-021-02086-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 10/13/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Phenylketonuria (PKU) is a rare inherited metabolic disorder caused by defects in the phenylalanine-hydroxylase gene (PAH), the enzyme catalyzing the conversion of phenylalanine to tyrosine. PAH impairment causes phenylalanine accumulation in the blood and brain, with a broad spectrum of pathophysiological and neurological consequences for patients. Prevalence of disease varies, with peaks in some regions and countries, including Italy. A recent expert survey described the real-life of clinical practice for PKU in Italy, revealing inhomogeneities in disease management, particularly concerning approach to pharmacotherapy with sapropterin hydrochloride, analogous of the natural PAH co-factor, allowing disease control in a subset of patients. Therefore, the purpose of this paper is to continue the work initiated with the expert survey paper, to provide national guidances aiming to harmonize and optimize patient care at a national level. PARTICIPANTS The Consensus Group, convened by 10 Steering Committee members, consisted of a multidisciplinary crowd of 46 experts in the management of PKU in Italy. CONSENSUS PROCESS The Steering Committee met in a series of virtual meeting in order to discuss on clinical focuses to be developed and analyzed in guidance statements, on the basis of expert practice based evidence, large systematic literature review previously performed in the expert survey paper, and evidence based consensus published. Statements were re-discussed and refined during consensus conferences in the widest audience of experts, and finally submitted to the whole consensus group for a modified-Delphi voting. RESULTS Seventy three statements, divided in two main clinical areas, PKU management and Pharmacotherapy, achieved large consensus in a multidisciplinary group of expert in different aspects of disease. Importantly, these statements involve guidances for the use of sapropterin dihydrochloride, still not sufficiently implemented in Italy, and a set of good practice to approach the use of novel enzyme replacement treatment pegvaliase. CONCLUSIONS This evidence-based consensus provides a minimum set of guidances for disease management to be implemented in all PKU centers. Moreover, these guidances represent the first statement for sapropterin dihydrochloride use, implementation and standardization in Italy, and a guide for approaching pegvaliase treatment at a national level on a consistent basis.
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Affiliation(s)
- Alberto Burlina
- Division of Inherited Metabolic Diseases, Reference Center for Expanded Newborn Screening, DIDAS Servizi Di Diagnostica Integrata, University Hospital Padova, 35128, Padua, Italy
| | - Giacomo Biasucci
- Maternal and Child Health Department, Pediatrics and Neonatology Unit, Guglielmo da Saliceto Hospital, 29121, Piacenza, Italy.
| | - Maria Teresa Carbone
- Pediatric Division, Metabolic and Rare Diseases, Santobono Pausilipon Hospital, 80122, Naples, Italy
| | - Chiara Cazzorla
- Division of Inherited Metabolic Diseases, Reference Center for Expanded Newborn Screening, DIDAS Servizi Di Diagnostica Integrata, University Hospital Padova, 35128, Padua, Italy
| | - Sabrina Paci
- Paediatric Department, ASST Santi Paolo E Carlo, San Paolo Hospital, University of Milan, 20142, Milan, Italy
| | - Francesca Pochiero
- Metabolic and Muscular Unit, A. Meyer Children's Hospital, Florence, Italy
| | - Marco Spada
- Department of Pediatrics, Regina Margherita Children's Hospital, University of Torino, 10126, Turin, Italy
| | - Albina Tummolo
- Metabolic Diseases Department, Clinical Genetics and Diabetology, Giovanni XXIII Children's Hospital, 70126, Bari, Italy
| | - Juri Zuvadelli
- Paediatric Department, ASST Santi Paolo E Carlo, San Paolo Hospital, University of Milan, 20142, Milan, Italy
| | - Vincenzo Leuzzi
- Department of Human Neuroscience, Unit of Child Neurology and Psychiatry, University La Sapienza, 00185, Rome, Italy
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Aitkenhead L, Krishna G, Ellerton C, Moinuddin M, Matcham J, Shiel L, Hossain S, Kiffin M, Foley J, Skeath R, Cleary M, Lachmann R, Murphy E. Long-term cognitive and psychosocial outcomes in adults with phenylketonuria. J Inherit Metab Dis 2021; 44:1353-1368. [PMID: 34145605 DOI: 10.1002/jimd.12413] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 05/31/2021] [Accepted: 06/16/2021] [Indexed: 12/22/2022]
Abstract
Previous studies have suggested that cognitive and psychosocial underfunctioning in early-treated adults with phenylketonuria (PKU) may be explained by suboptimal adherence to dietary treatments, however, these studies often employ small samples, with different outcome measures, definitions and cut-offs. Samples have also tended to comprise participants with a limited range of blood phenylalanine concentrations, and often individuals who may not have been treated early enough to avoid neurological damage. In this study, we explore the impact of lifetime dietary control, as indicated by blood phenylalanine concentrations in childhood, adolescence and adulthood, on long-term cognitive and psychosocial outcomes in a large sample of adults with PKU who were diagnosed by neonatal screening and commenced on dietary treatment within the first month of life. One hundred and fifty-four participants underwent cognitive testing, assessing attention, learning, working memory, language, executive functioning and processing speed. One hundred and forty-nine completed measures of psychosocial functioning, documenting educational, occupational, quality of life, emotional and social outcomes which were compared with a group of healthy controls. Many adults with PKU demonstrated cognitive impairments, most frequently affecting processing speed (23%), executive function (20%) and learning (12%). Cognitive outcomes were related to measures of historic metabolic control, but only processing speed was significantly related to phenylalanine concentration at the time of testing after controlling for historic levels. Adults with PKU did not, however, differ from controls in educational, occupational, quality of life or emotional outcomes, or on a measure of family functioning, and showed only minor differences in relationship style. These findings have implications for patient counselling and decisions regarding the management of PKU in adulthood.
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Affiliation(s)
- Lynne Aitkenhead
- Charles Dent Metabolic Unit, National Hospital for Neurology and Neurosurgery, London, UK
- UCL Institute of Neurology, London, UK
| | - Gauri Krishna
- Charles Dent Metabolic Unit, National Hospital for Neurology and Neurosurgery, London, UK
| | - Charlotte Ellerton
- Charles Dent Metabolic Unit, National Hospital for Neurology and Neurosurgery, London, UK
| | - Md Moinuddin
- UCL Institute of Child Health, London, UK
- Faculty of Health, Social Care & Medicine, Edge Hill University, Ormskirk, UK
| | - Jessica Matcham
- Charles Dent Metabolic Unit, National Hospital for Neurology and Neurosurgery, London, UK
| | - Lisha Shiel
- Charles Dent Metabolic Unit, National Hospital for Neurology and Neurosurgery, London, UK
| | - Shasoty Hossain
- Charles Dent Metabolic Unit, National Hospital for Neurology and Neurosurgery, London, UK
| | - Marianne Kiffin
- Charles Dent Metabolic Unit, National Hospital for Neurology and Neurosurgery, London, UK
| | - Jennifer Foley
- UCL Institute of Neurology, London, UK
- Department of Neuropsychology, National Hospital of Neurology & Neurosurgery, London, UK
| | - Rachel Skeath
- Department of Metabolic Medicine, Great Ormond Street Hospital, London, UK
| | - Maureen Cleary
- Department of Metabolic Medicine, Great Ormond Street Hospital, London, UK
- Great Ormond Street Hospital NIHR Biomedical Research Centre, London, UK
| | - Robin Lachmann
- Charles Dent Metabolic Unit, National Hospital for Neurology and Neurosurgery, London, UK
- UCL Institute of Neurology, London, UK
| | - Elaine Murphy
- Charles Dent Metabolic Unit, National Hospital for Neurology and Neurosurgery, London, UK
- UCL Institute of Neurology, London, UK
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20
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Kenneson A, Singh RH. Natural history of children and adults with phenylketonuria in the NBS-PKU Connect registry. Mol Genet Metab 2021; 134:243-249. [PMID: 34654619 DOI: 10.1016/j.ymgme.2021.10.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 10/01/2021] [Accepted: 10/02/2021] [Indexed: 11/24/2022]
Abstract
PURPOSE Phenylalanine hydroxylase deficiency, or phenylketonuria (PKU), is a rare autosomal recessive metabolic disorder. Early diagnosis via newborn screening (NBS) and initiation of treatment prevent the development of cognitive impairment and other co-morbidities. The purpose of this study is to describe the natural history of PKU in the United States, including prevalence of co-morbidities and predictors of outcomes. METHODS We analyzed data from a self-report survey in the NBS-PKU Connect online registry. We describe the participants' nutrition management strategies, barriers to management, outcomes of bone disorders, skin, and psychological co-morbidities, and the use of special education or other special services. Predictors of outcomes were identified and assessed, including the impact of sex, age, age at diagnosis, blood phenylalanine concentration, use of sapropterin, use of medical food, adherence to prescribed diet, use of low protein modified foods, whether they had ever been off-diet, and use of tyrosine supplementation. RESULTS The 219 respondents included individuals with PKU or hyperphenylalanemia (n = 78), or their caregivers (n = 141). Most (84.3%) started treatment before the age of two weeks. About one-third indicated that they had been off-diet at some point in their lives, and 81.4% reported that they currently adhered to their prescribed diet, with adherence to prescribed diet decreasing with age. Blood phenylalanine concentration was under the recommended threshold of 360 μmol/L for 68.5% of participants. One-quarter of respondents reported psychological co-morbidities, with anxiety and ADD/ADHD being the most common. The incidence of psychological co-morbidities increased with age and with ever having been off diet. Special education or other special services were more likely to be reported by individuals who were diagnosed after one week of age. Skin disorders such as acne and eczema were more common in females than males, and a minority of participants reported bone disorders. CONCLUSIONS Despite recommendations to maintain blood phenylalanine concentrations in the therapeutic range throughout life, it is not uncommon for adults with PKU to discontinue dietary management of their disorder. Early diagnosis was associated with reduced need for special education or other special services, and continuous treatment was associated with decreased psychological co-morbidities.
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Affiliation(s)
- Aileen Kenneson
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, United States of America.
| | - Rani H Singh
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, United States of America; Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, United States of America.
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21
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Abstract
Phenylketonuria (PKU; also known as phenylalanine hydroxylase (PAH) deficiency) is an autosomal recessive disorder of phenylalanine metabolism, in which especially high phenylalanine concentrations cause brain dysfunction. If untreated, this brain dysfunction results in severe intellectual disability, epilepsy and behavioural problems. The prevalence varies worldwide, with an average of about 1:10,000 newborns. Early diagnosis is based on newborn screening, and if treatment is started early and continued, intelligence is within normal limits with, on average, some suboptimal neurocognitive function. Dietary restriction of phenylalanine has been the mainstay of treatment for over 60 years and has been highly successful, although outcomes are still suboptimal and patients can find the treatment difficult to adhere to. Pharmacological treatments are available, such as tetrahydrobiopterin, which is effective in only a minority of patients (usually those with milder PKU), and pegylated phenylalanine ammonia lyase, which requires daily subcutaneous injections and causes adverse immune responses. Given the drawbacks of these approaches, other treatments are in development, such as mRNA and gene therapy. Even though PAH deficiency is the most common defect of amino acid metabolism in humans, brain dysfunction in individuals with PKU is still not well understood and further research is needed to facilitate development of pathophysiology-driven treatments.
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Affiliation(s)
- Francjan J van Spronsen
- Beatrix Children's Hospital, University Medical Centre Groningen, University of Groningen, Groningen, Netherlands.
| | - Nenad Blau
- University Children's Hospital in Zurich, Zurich, Switzerland
| | - Cary Harding
- Department of Molecular and Medical Genetics and Department of Pediatrics, Oregon Health & Science University, Oregon, USA
| | | | - Nicola Longo
- Department of Pediatrics, University of Utah, Salt Lake City, Utah, USA
| | - Annet M Bosch
- University of Amsterdam, Department of Pediatrics, Division of Metabolic Disorders, Emma Children's Hospital, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
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22
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van Wegberg A, Evers R, Burgerhof J, van Dam E, Heiner-Fokkema MR, Janssen M, de Vries MC, van Spronsen FJ. Effect of BH4 on blood phenylalanine and tyrosine variations in patients with phenylketonuria. Mol Genet Metab 2021; 133:49-55. [PMID: 33766497 DOI: 10.1016/j.ymgme.2021.02.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 02/26/2021] [Accepted: 02/26/2021] [Indexed: 02/06/2023]
Abstract
BACKGROUND In patients with phenylketonuria, stability of blood phenylalanine and tyrosine concentrations might influence brain chemistry and therefore patient outcome. This study prospectively investigated the effects of tetrahydrobiopterin (BH4), as a chaperone of phenylalanine hydroxylase on diurnal and day-to-day variations of blood phenylalanine and tyrosine concentrations. METHODS Blood phenylalanine and tyrosine were measured in dried blood spots (DBS) four times daily for 2 days (fasting, before lunch, before dinner, evening) and once daily (fasting) for 6 days in a randomized cross-over design with a period with BH4 and a period without BH4. The sequence was randomized. Eleven proven BH4 responsive PKU patients participated, 5 of them used protein substitutes during BH4 treatment. Natural protein intake and protein substitute dosing was adjusted during the period without BH4 in order to keep DBS phenylalanine levels within target range. Patients filled out a 3-day food diary during both study periods. Variations of DBS phenylalanine and Tyr were expressed in standard deviations (SD) and coefficient of variation (CV). RESULTS BH4 treatment did not significantly influence day-to-day phenylalanine and tyrosine variations nor diurnal phenylalanine variations, but decreased diurnal tyrosine variations (median SD 17.6 μmol/l, median CV 21.3%, p = 0.01) compared to diet only (median SD 34.2 μmol/l, median CV 43.2%). Consequently, during BH4 treatment diurnal phenylalanine/tyrosine ratio variation was smaller, while fasting tyrosine levels tended to be higher. CONCLUSION BH4 did not impact phenylalanine variation but decreased diurnal tyrosine and phenylalanine/tyrosine ratio variations, possibly explained by less use of protein substitute and increased tyrosine synthesis.
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Affiliation(s)
- Amj van Wegberg
- Division of Metabolic Diseases, Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, the Netherlands
| | - Raf Evers
- Division of Metabolic Diseases, Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, the Netherlands
| | - Jgm Burgerhof
- Department of Epidemiology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - E van Dam
- Division of Metabolic Diseases, Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, the Netherlands
| | - M R Heiner-Fokkema
- Department of Laboratory Medicine, Laboratory of Metabolic Diseases, University of Groningen, University Medical Centre Groningen, the Netherlands
| | - McH Janssen
- Department of Internal Medicine, Radboudumc, Nijmegen, the Netherlands
| | - M C de Vries
- Department of Pediatrics, Radboudumc Nijmegen, the Netherlands
| | - F J van Spronsen
- Division of Metabolic Diseases, Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, the Netherlands.
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23
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Waisbren S, Burton BK, Feigenbaum A, Konczal LL, Lilienstein J, McCandless SE, Rowell R, Sanchez-Valle A, Whitehall KB, Longo N. Long-term preservation of intellectual functioning in sapropterin-treated infants and young children with phenylketonuria: A seven-year analysis. Mol Genet Metab 2021; 132:119-127. [PMID: 33485801 PMCID: PMC8684368 DOI: 10.1016/j.ymgme.2021.01.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 01/04/2021] [Accepted: 01/04/2021] [Indexed: 11/19/2022]
Abstract
Sapropterin dihydrochloride has been approved for the treatment of hyperphenylalaninemia in infants and young children with phenylketonuria (PKU). Sapropterin can reduce phenylalanine (Phe) levels in tetrahydrobiopterin (BH4)-responsive patients, potentially preventing the intellectual impairment caused by elevated Phe levels. The long-term effect of sapropterin on intellectual functioning was assessed using the Full-Scale Intelligence Quotient (FSIQ) in 62 children who began treatment before the age of 6 years. Over each 2-year interval, the estimate of mean change in FSIQ was -0.5768 with a lower limit of the 95% confidence interval (CI) of -1.60. At the end of the follow-up period (Year 7), the least squares mean estimate of the change in FSIQ from baseline was 1.14 with a lower limit of the 95% CI of -3.53. These lower limits were both within the clinically expected variation of 5 points. During the whole study period, mean blood Phe levels remained within the American College of Medical Genetics (ACMG) target range of 120-360 μmol/L. In addition, height, weight, and head circumference were maintained within normal ranges throughout follow-up, as defined by growth charts from the World Health Organization (WHO) and Centers for Disease Control and Prevention (CDC) for children below and above the age of 24 months, respectively. All patients (n = 65) enrolled in this study experienced at least one adverse event, as expected from previous studies. In conclusion, long-term use of sapropterin in individuals with PKU helps to control blood Phe, preserve intellectual functioning, and maintain normal growth in BH4-responsive children who initiated treatment between the ages of 0 to 6 years.
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Affiliation(s)
- Susan Waisbren
- Harvard Medical School, Boston Children's Hospital, Boston, MA, USA
| | - Barbara K Burton
- Ann & Robert H. Lurie Children's Hospital, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Annette Feigenbaum
- The Hospital for Sick Children and University of Toronto, Toronto, Ontario, Canada
| | - Laura L Konczal
- Center for Human Genetics, University Hospitals Cleveland Medical Center and Case Western Reserve University, Cleveland, OH, USA
| | | | - Shawn E McCandless
- Section of Genetics and Metabolism, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Children's Hospital Colorado, Aurora, CO, USA
| | | | | | | | - Nicola Longo
- Division of Medical Genetics, Department of Pediatrics, University of Utah, Salt Lake City, UT, USA.
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24
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Diffusion kurtosis imaging detects subclinical white matter abnormalities in Phenylketonuria. NEUROIMAGE-CLINICAL 2021; 29:102555. [PMID: 33461111 PMCID: PMC7814191 DOI: 10.1016/j.nicl.2020.102555] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 12/02/2020] [Accepted: 12/29/2020] [Indexed: 12/19/2022]
Abstract
OBJECTIVE Phenylketonuria (PKU) is an autosomal recessive disorder whereby deficiencies in phenylalanine metabolism cause progressive neurological dysfunction. Managing PKU is challenging, with disease monitoring focussed on short-term phenylalanine control rather than measures of neuronal damage. Conventional imaging lacks sensitivity, however diffusion kurtosis imaging (DKI), a new MRI method may reveal subclinical white matter structural changes in PKU. METHODS This cohort study involved adults with PKU recruited during routine clinical care. MRI, neurocognitive assessment and historical phenylalanine (Phe) levels were collected. A hypothesis-generating case study comparing diet-compliant and non-compliant siblings confirmed that DKI metrics are sensitive to dietary adherence and prompted a candidate metric (Krad/KFA ratio). We then tested this metric in a Replication cohort (PKU = 20; controls = 43). RESULTS Both siblings scored outside the range of controls for all DKI-based metrics, with severe changes in the periventricular white matter and a gradient of severity toward the cortex. Krad/KFA provided clear separation by diagnosis in the Replication cohort (p < 0.001 in periventricular, deep and pericortical compartments). The ratio also correlated negatively with attention (r = -0.51 & -0.50, p < 0.05) and positively with 3-year mean Phe (r = 0.45 & 0.58, p < 0.01). CONCLUSION DKI reveals regionally-specific, progressive abnormalities of brain diffusion characteristics in PKU, even in the absence of conspicuous clinical signs or abnormalities on conventional MRI. A DKI-based marker derived from these scores (Krad/KFA ratio) was sensitive to cognitive impairment and PKU control over the medium term and may provide a meaningful subclinical biomarker of end-organ damage.
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25
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Clocksin HE, Hawks ZW, White DA, Christ SE. Inter- and intra-tract analysis of white matter abnormalities in individuals with early-treated phenylketonuria (PKU). Mol Genet Metab 2021; 132:11-18. [PMID: 33334682 DOI: 10.1016/j.ymgme.2020.12.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 12/02/2020] [Accepted: 12/02/2020] [Indexed: 11/22/2022]
Abstract
Even with early and continuous treatment, individuals with phenylketonuria (PKU) may exhibit abnormalities of cortical white matter (WM). The present study utilizes a new analysis approach called Automated Fiber-Tract Quantification (AFQ) to advance our understanding of the tract-specific patterns of change in WM abnormalities in individuals with early-treated PKU (ETPKU). Diffusion Tensor Imaging (DTI) data from a sample of 22 individuals with ETPKU and a demographically-matched sample of 21 healthy individuals without PKU was analyzed using AFQ. In addition, a subsample of 8 individuals with ETPKU was reevaluated six months later after demonstrating a significant reduction in blood phe levels following initiation of sapropterin treatment. Within-tract AFQ analyses revealed significant location-by-group interactions for several WM tracts throughout the brain. In most cases, ETPKU-related disruptions in mean diffusivity (MD) were more apparent in posterior (as compared to anterior) aspects of a given tract. Reduction in blood phe levels with the aforementioned ETPKU subsample was associated with a similar pattern of improvement (posterior-to-anterior) within most tracts. Taken together, these findings suggest that there is a systematic pattern of change in WM abnormalities in individuals with ETPKU in a posterior-to-anterior manner along individual WM tracts.
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Affiliation(s)
- Hayley E Clocksin
- Department of Psychological Sciences, University of Missouri, Columbia, MO, 65211, USA
| | - Zoë W Hawks
- Department of Psychological and Brain Sciences, Washington University in St. Louis, St. Louis, MO, 63130, USA
| | - Desirée A White
- Department of Psychological and Brain Sciences, Washington University in St. Louis, St. Louis, MO, 63130, USA
| | - Shawn E Christ
- Department of Psychological Sciences, University of Missouri, Columbia, MO, 65211, USA.
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26
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Kraleva D, Evans S, Pinto A, Daly A, Ashmore C, Pointon-Bell K, Rocha JC, MacDonald A. Protein Labelling Accuracy for UK Patients with PKU Following a Low Protein Diet. Nutrients 2020; 12:nu12113440. [PMID: 33182603 PMCID: PMC7696494 DOI: 10.3390/nu12113440] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 10/23/2020] [Accepted: 10/27/2020] [Indexed: 01/02/2023] Open
Abstract
A phenylalanine (protein)-restricted diet is the primary treatment for phenylketonuria (PKU). Patients are dependent on food protein labelling to successfully manage their condition. We evaluated the accuracy of protein labelling on packaged manufactured foods from supermarket websites for foods that may be eaten as part of a phenylalanine-restricted diet. Protein labelling information was evaluated for 462 food items (“free from”, n = 159, regular, n = 303), divided into 16 food groups using supermarket website data. Data collection included protein content per portion/100 g when food was “as sold”, “cooked” or “prepared”; cooking methods, and preparation instructions. Labelling errors affecting protein content were observed in every food group, with overall protein labelling unclear in 55% (n = 255/462) of foods. There was misleading, omitted, or erroneous (MOE) information in 43% (n = 68/159) of “free from” foods compared with 62% (n = 187/303) of regular foods, with fewer inaccuracies in “free from” food labelling (p = 0.007). Protein analysis was available for uncooked weight only but not cooked weight for 58% (n = 85/146) of foods; 4% (n = 17/462) had misleading protein content. There was a high rate of incomplete, misleading, or inaccurate data affecting the interpretation of the protein content of food items on supermarket websites. This could adversely affect metabolic control of patients with PKU and warrants serious consideration.
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Affiliation(s)
- Dilyana Kraleva
- Faculty of Health, Education & Life Sciences, Birmingham City University City South Campus, Westbourne Road, Edgbaston, Birmingham B15 3TN, UK; (D.K.); (K.P.-B.)
| | - Sharon Evans
- Birmingham Women’s and Children’s NHS Foundation Trust, Steelhouse Lane, Birmingham B4 6NH, UK; (S.E.); (A.P.); (A.D.); (C.A.)
| | - Alex Pinto
- Birmingham Women’s and Children’s NHS Foundation Trust, Steelhouse Lane, Birmingham B4 6NH, UK; (S.E.); (A.P.); (A.D.); (C.A.)
| | - Anne Daly
- Birmingham Women’s and Children’s NHS Foundation Trust, Steelhouse Lane, Birmingham B4 6NH, UK; (S.E.); (A.P.); (A.D.); (C.A.)
| | - Catherine Ashmore
- Birmingham Women’s and Children’s NHS Foundation Trust, Steelhouse Lane, Birmingham B4 6NH, UK; (S.E.); (A.P.); (A.D.); (C.A.)
| | - Kiri Pointon-Bell
- Faculty of Health, Education & Life Sciences, Birmingham City University City South Campus, Westbourne Road, Edgbaston, Birmingham B15 3TN, UK; (D.K.); (K.P.-B.)
| | - Júlio César Rocha
- Nutrition & Metabolism, NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Campo Mártires da Pátria, 130, 1169-056 Lisbon, Portugal;
- Center for Health Technology and Services Research (CINTESIS), R. Dr. Plácido da Costa, s/n, 4200-450 Porto, Portugal
| | - Anita MacDonald
- Birmingham Women’s and Children’s NHS Foundation Trust, Steelhouse Lane, Birmingham B4 6NH, UK; (S.E.); (A.P.); (A.D.); (C.A.)
- Correspondence:
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27
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Cognitive Outcomes and Relationships with Phenylalanine in Phenylketonuria: A Comparison between Italian and English Adult Samples. Nutrients 2020; 12:nu12103033. [PMID: 33022955 PMCID: PMC7599948 DOI: 10.3390/nu12103033] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 09/23/2020] [Accepted: 09/24/2020] [Indexed: 02/06/2023] Open
Abstract
We aimed to assess if the same cognitive batteries can be used cross-nationally to monitor the effect of Phenylketonuria (PKU). We assessed whether a battery, previously used with English adults with PKU (AwPKU), was also sensitive to impairments in Italian AwPKU. From our original battery, we selected a number of tasks that comprehensively assessed visual attention, visuo-motor coordination, executive functions (particularly, reasoning, planning, and monitoring), sustained attention, and verbal and visual memory and learning. When verbal stimuli/or responses were involved, stimuli were closely matched between the two languages for psycholinguistic variables. We administered the tasks to 19 Italian AwPKU and 19 Italian matched controls and compared results from with 19 English AwPKU and 19 English matched controls selected from a previously tested cohort. Participant election was blind to cognitive performance and metabolic control, but participants were closely matched for age and education. The Italian AwPKU group had slightly worse metabolic control but showed levels of performance and patterns of impairment similar to the English AwPKU group. The Italian results also showed extensive correlations between adult cognitive measures and metabolic measures across the life span, both in terms of Phenylalanine (Phe) levels and Phe fluctuations, replicating previous results in English. These results suggest that batteries with the same and/or matched tasks can be used to assess cognitive outcomes across countries allowing results to be compared and accrued. Future studies should explore potential differences in metabolic control across countries to understand what variables make metabolic control easier to achieve.
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28
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Rocha JC, Calhau C, MacDonald A. Reply to Jakovac; Severity of COVID-19 infection in patients with phenylketonuria: is vitamin D status protective? Am J Physiol Endocrinol Metab 2020; 318:E890-E891. [PMID: 32479158 PMCID: PMC7276976 DOI: 10.1152/ajpendo.00195.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Júlio César Rocha
- Nutrition & Metabolism, Nova Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisbon, Portugal
- Center for Health Technology and Services Research (CINTESIS), Porto, Portugal
| | - Conceição Calhau
- Nutrition & Metabolism, Nova Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisbon, Portugal
- Center for Health Technology and Services Research (CINTESIS), Porto, Portugal
| | - Anita MacDonald
- Department of Dietetics, Birmingham Children's Hospital, Birmingham, United Kingdom
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