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Pinto A, Ahring K, Almeida MF, Ashmore C, Bélanger-Quintana A, Burlina A, Coşkun T, Daly A, van Dam E, Dursun A, Evans S, Feillet F, Giżewska M, Gökmen-Özel H, Hickson M, Hoekstra Y, Ilgaz F, Jackson R, Leśniak A, Loro C, Malicka K, Patalan M, Rocha JC, Sivri S, Rodenburg I, van Spronsen F, Strączek K, Tokatli A, MacDonald A. Blood Phenylalanine Levels in Patients with Phenylketonuria from Europe between 2012 and 2018: Is It a Changing Landscape? Nutrients 2024; 16:2064. [PMID: 38999811 PMCID: PMC11243388 DOI: 10.3390/nu16132064] [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: 05/28/2024] [Revised: 06/18/2024] [Accepted: 06/20/2024] [Indexed: 07/14/2024] Open
Abstract
BACKGROUND In 2011, a European phenylketonuria (PKU) survey reported that the blood phenylalanine (Phe) levels were well controlled in early life but deteriorated with age. Other studies have shown similar results across the globe. Different target blood Phe levels have been used throughout the years, and, in 2017, the European PKU guidelines defined new targets for blood Phe levels. This study aimed to evaluate blood Phe control in patients with PKU across Europe. METHODS nine centres managing PKU in Europe and Turkey participated. Data were collected retrospectively from medical and dietetic records between 2012 and 2018 on blood Phe levels, PKU severity, and medications. RESULTS A total of 1323 patients (age range:1-57, 51% male) participated. Patient numbers ranged from 59 to 320 in each centre. The most common phenotype was classical PKU (n = 625, 48%), followed by mild PKU (n = 357, 27%) and hyperphenylalaninemia (HPA) (n = 325, 25%). The mean percentage of blood Phe levels within the target range ranged from 65 ± 54% to 88 ± 49% for all centres. The percentage of Phe levels within the target range declined with increasing age (<2 years: 89%; 2-5 years: 84%; 6-12 years: 73%; 13-18 years: 85%; 19-30 years: 64%; 31-40 years: 59%; and ≥41 years: 40%). The mean blood Phe levels were significantly lower and the percentage within the target range was significantly higher (p < 0.001) in patients with HPA (290 ± 325 μmol/L; 96 ± 24%) and mild PKU (365 ± 224 μmol/L; 77 ± 36%) compared to classical PKU (458 ± 350 μmol/L, 54 ± 46%). There was no difference between males and females in the mean blood Phe levels (p = 0.939), but the percentage of Phe levels within the target range was higher in females among school-age children (6-12 years; 83% in females vs. 78% in males; p = 0.005), adolescents (13-18 years; 62% in females vs. 59% in males; p = 0.034) and adults (31-40 years; 65% in females vs. 41% in males; p < 0.001 and >41 years; 43% in females vs. 28% in males; p < 0.001). Patients treated with sapropterin (n = 222) had statistically significantly lower Phe levels compared to diet-only-treated patients (mean 391 ± 334 μmol/L; percentage within target 84 ± 39% vs. 406 ± 334 μmol/L; 73 ± 41%; p < 0.001), although a blood Phe mean difference of 15 µmol/L may not be clinically relevant. An increased frequency of blood Phe monitoring was associated with better metabolic control (p < 0.05). The mean blood Phe (% Phe levels within target) from blood Phe samples collected weekly was 271 ± 204 μmol/L, (81 ± 33%); for once every 2 weeks, it was 376 ± 262 μmol/L, (78 ± 42%); for once every 4 weeks, it was 426 ± 282 μmol/L, (71 ± 50%); and less than monthly samples, it was 534 ± 468 μmol/L, (70 ± 58%). CONCLUSIONS Overall, blood Phe control deteriorated with age. A higher frequency of blood sampling was associated with better blood Phe control with less variability. The severity of PKU and the available treatments and resources may impact the blood Phe control achieved by each treatment centre.
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Affiliation(s)
- Alex Pinto
- Birmingham Children's Hospital, Birmingham B4 6NH, UK
- School of Health Professions, Faculty of Health, University of Plymouth, Plymouth PL4 8AA, UK
| | - Kirsten Ahring
- Departments of Paediatrics and Clinical Genetics, PKU Clinic, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Manuela Ferreira Almeida
- Centro de Genética Médica, Unidade Local de Saúde de Santo António, E.P.E. (ULSSA), 4099-028 Porto, Portugal
- Centro de Referência na área de Doenças Hereditárias do Metabolismo, Unidade Local de Saúde de Santo António, E.P.E. (ULSSA), 4099-001 Porto, Portugal
- Unit for Multidisciplinary Research in Biomedicine, Abel Salazar Institute of Biomedical Sciences, University of Porto-UMIB/ICBAS/UP, 4050-313 Porto, Portugal
| | | | - Amaya Bélanger-Quintana
- Unidad de Enfermedades Metabólicas Congénitas, Hospital Universitario Ramón y Cajal, 28034 Madrid, Spain
| | - Alberto Burlina
- Division of Inherited Metabolic Diseases, Reference Centre Expanded Newborn Screening, Department of Women's and Children's Health, University Hospital, 35128 Padova, Italy
| | - Turgay Coşkun
- Division of Pediatric Metabolism, Department of Pediatrics, Faculty of Medicine, Hacettepe University, Gevher Nesibe Cd., 06230 Ankara, Turkey
| | - Anne Daly
- Birmingham Children's Hospital, Birmingham B4 6NH, UK
| | - Esther van Dam
- Division of Metabolic Diseases, Beatrix Children's Hospital, University Medical Centre Groningen, University of Groningen, Hanzeplein 1, 9700 RB Groningen, The Netherlands
| | - Ali Dursun
- Division of Pediatric Metabolism, Department of Pediatrics, Faculty of Medicine, Hacettepe University, Gevher Nesibe Cd., 06230 Ankara, Turkey
| | - Sharon Evans
- Birmingham Children's Hospital, Birmingham B4 6NH, UK
| | - François Feillet
- Department of Paediatrics, Reference Center for Inborn Errors of Metabolism, Hôpital d'Enfants Brabois, CHU Nancy, 54500 Vandoeuvre les Nancy, France
| | - Maria Giżewska
- Department of Pediatrics, Endocrinology, Diabetology, Metabolic Diseases and Cardiology, Pomeranian Medical University, 70-204 Szczecin, Poland
| | - Hulya Gökmen-Özel
- Department of Nutrition and Dietetics, Faculty of Health Sciences, Hacettepe University, 06100 Ankara, Turkey
| | - Mary Hickson
- School of Health Professions, Faculty of Health, University of Plymouth, Plymouth PL4 8AA, UK
| | - Yteke Hoekstra
- Division of Metabolic Diseases, Beatrix Children's Hospital, University Medical Centre Groningen, University of Groningen, Hanzeplein 1, 9700 RB Groningen, The Netherlands
| | - Fatma Ilgaz
- Department of Nutrition and Dietetics, Faculty of Health Sciences, Hacettepe University, 06100 Ankara, Turkey
| | - Richard Jackson
- Cancer Research UK Liverpool Cancer Trials Unit, University of Liverpool, Liverpool L69 3GL, UK
| | - Alicja Leśniak
- Department of Pediatrics, Endocrinology, Diabetology, Metabolic Diseases and Cardiology, Pomeranian Medical University, 70-204 Szczecin, Poland
| | - Christian Loro
- Division of Inherited Metabolic Diseases, Reference Centre Expanded Newborn Screening, Department of Women's and Children's Health, University Hospital, 35128 Padova, Italy
| | - Katarzyna Malicka
- Department of Pediatrics, Endocrinology, Diabetology, Metabolic Diseases and Cardiology, Pomeranian Medical University, 70-204 Szczecin, Poland
| | - Michał Patalan
- Department of Pediatrics, Endocrinology, Diabetology, Metabolic Diseases and Cardiology, Pomeranian Medical University, 70-204 Szczecin, Poland
| | - Júlio César Rocha
- Nutrition and Metabolism, NOVA Medical School (NMS), Faculdade de Ciências Médicas, (FCM), Universidade Nova de Lisboa, 1169-056 Lisboa, Portugal
- Centro de Investigação em Tecnologias e Serviços de Saúde (CINTESIS), NOVA Medical School (NMS), Faculdade de Ciências Médicas, (FCM), Universidade Nova de Lisboa, 1169-056 Lisboa, Portugal
- Reference Centre of Inherited Metabolic Diseases, Unidade Local de Saúde, 1169-045 Lisboa, Portugal
- Comprehensive Health Research Centre (CHRC), NOVA Medical School, (NMS), Faculdade de Ciências Médicas (FCM), Universidade Nova de Lisboa, 1169-056 Lisboa, Portugal
| | - Serap Sivri
- Division of Pediatric Metabolism, Department of Pediatrics, Faculty of Medicine, Hacettepe University, Gevher Nesibe Cd., 06230 Ankara, Turkey
| | - Iris Rodenburg
- Division of Metabolic Diseases, Beatrix Children's Hospital, University Medical Centre Groningen, University of Groningen, Hanzeplein 1, 9700 RB Groningen, The Netherlands
| | - Francjan van Spronsen
- Division of Metabolic Diseases, Beatrix Children's Hospital, University Medical Centre Groningen, University of Groningen, Hanzeplein 1, 9700 RB Groningen, The Netherlands
| | - Kamilla Strączek
- Department of Pediatrics, Endocrinology, Diabetology, Metabolic Diseases and Cardiology, Pomeranian Medical University, 70-204 Szczecin, Poland
| | - Ayşegül Tokatli
- Division of Pediatric Metabolism, Department of Pediatrics, Faculty of Medicine, Hacettepe University, Gevher Nesibe Cd., 06230 Ankara, Turkey
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Karaca Sahin M, Aktuglu Zeybek AC, Zubarioglu T, Cansever MS, Kıykım E. Comparison of Cost Analysis in Patients with Tetrahydrobiopterin-Responsive and Non-Responsive Phenylketonuria in Turkey. Nutrients 2024; 16:1444. [PMID: 38794682 PMCID: PMC11124297 DOI: 10.3390/nu16101444] [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: 12/02/2023] [Revised: 12/19/2023] [Accepted: 01/08/2024] [Indexed: 05/26/2024] Open
Abstract
Phenylketonuria is an inherited metabolic disorder that leads to neurobehavioral dysfunction. The main treatment is a low-phenylalanine diet and/or the cofactor tetrahydrobiopterin. Regular outpatient follow-up care and measurement of the phenylalanine levels in the blood are required. We aimed to analyze the economic burden of phenylketonuria on families and the state. The patients with phenylketonuria were divided into three groups according to their treatment: a low-phenylalanine diet group (n = 50), a tetrahydrobiopterin group (n = 44), and a group taking tetrahydrobiopterin together with the diet (n = 25). A comparative cost analysis was carried out. The annual economic burden to the state was calculated to average EUR 18,801 ± 15,345 and was lowest in the diet group, then in the tetrahydrobiopterin group, and highest in the tetrahydrobiopterin + diet group (p < 0.001). Out-of-pocket costs amounted to EUR 1531 ± 1173 per year, and indirect losses averaged EUR 2125 ± 1930 per year for all families. The economic loss was significantly lower in the families taking tetrahydrobiopterin than in the other groups (p = 0.001). The combined use of medical nutrition and BH4 treatments has been shown to increase the economic burden on the state. Reimbursing low-protein products and increasing the number of patients eligible for financial allowances may reduce the economic burden on families.
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Affiliation(s)
- Merve Karaca Sahin
- Department of Pediatrics, Cerrahpasa Medical Faculty, Istanbul University-Cerrahpasa, 34098 Istanbul, Turkey;
| | - Ayse Cigdem Aktuglu Zeybek
- Division of Nutrition and Metabolism, Department of Pediatrics, Cerrahpasa Medical Faculty, Istanbul University-Cerrahpasa, 34098 Istanbul, Turkey; (A.C.A.Z.); (T.Z.)
| | - Tanyel Zubarioglu
- Division of Nutrition and Metabolism, Department of Pediatrics, Cerrahpasa Medical Faculty, Istanbul University-Cerrahpasa, 34098 Istanbul, Turkey; (A.C.A.Z.); (T.Z.)
| | - Mehmet Serif Cansever
- Division of Medical Laboratory Techniques, Department of Medical Documentation and Techniques, The Vocational School of Health Services, Istanbul University-Cerrahpasa, 34295 Istanbul, Turkey;
| | - Ertugrul Kıykım
- Division of Nutrition and Metabolism, Department of Pediatrics, Cerrahpasa Medical Faculty, Istanbul University-Cerrahpasa, 34098 Istanbul, Turkey; (A.C.A.Z.); (T.Z.)
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Trefz F, Frauendienst-Egger G, Dienel G, Cannet C, Schmidt-Mader B, Haas D, Blau N, Himmelreich N, Spraul M, Freisinger P, Dobrowolski S, Berg D, Pilotto A. Does hyperphenylalaninemia induce brain glucose hypometabolism? Cerebral spinal fluid findings in treated adult phenylketonuric patients. Mol Genet Metab 2024; 142:108464. [PMID: 38537426 DOI: 10.1016/j.ymgme.2024.108464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 03/21/2024] [Accepted: 03/22/2024] [Indexed: 05/08/2024]
Abstract
Despite numerous studies in human patients and animal models for phenylketonuria (PKU; OMIM#261600), the pathophysiology of PKU and the underlying causes of brain dysfunction and cognitive problems in PKU patients are not well understood. In this study, lumbar cerebral spinal fluid (CSF) was obtained immediately after blood sampling from early-treated adult PKU patients who had fasted overnight. Metabolite and amino acid concentrations in the CSF of PKU patients were compared with those of non-PKU controls. The CSF concentrations and CSF/plasma ratios for glucose and lactate were found to be below normal, similar to what has been reported for glucose transporter1 (GLUT1) deficiency patients who exhibit many of the same clinical symptoms as untreated PKU patients. CSF glucose and lactate levels were negatively correlated with CSF phenylalanine (Phe), while CSF glutamine and glutamate levels were positively correlated with CSF Phe levels. Plasma glucose levels were negatively correlated with plasma Phe concentrations in PKU subjects, which partly explains the reduced CSF glucose concentrations. Although brain glucose concentrations are unlikely to be low enough to impair brain glucose utilization, it is possible that the metabolism of Phe in the brain to produce phenyllactate, which can be transported across the blood-brain barrier to the blood, may consume glucose and/or lactate to generate the carbon backbone for glutamate. This glutamate is then converted to glutamine and carries the Phe-derived ammonia from the brain to the blood. While this mechanism remains to be tested, it may explain the correlations of CSF glutamine, glucose, and lactate concentrations with CSF Phe.
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Affiliation(s)
- Friedrich Trefz
- Heidelberg University, Medical Faculty of Heidelberg, Center for Child and Adolescent Medicine, Division of Child Neurology and Metabolic Medicine, Heidelberg, Germany.
| | | | - Gerald Dienel
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, AR, United States; Department of Cell Biology and Physiology, University of New Mexico, Albuquerque, NM, United States
| | | | - Brigitte Schmidt-Mader
- Heidelberg University, Medical Faculty of Heidelberg, Center for Child and Adolescent Medicine, Division of Child Neurology and Metabolic Medicine, Heidelberg, Germany
| | - Dorothea Haas
- Heidelberg University, Medical Faculty of Heidelberg, Center for Child and Adolescent Medicine, Division of Child Neurology and Metabolic Medicine, Heidelberg, Germany
| | - Nenad Blau
- University Children's Hospital Zürich, Zürich, Switzerland
| | | | | | - Peter Freisinger
- Klinikum Reutlingen, Department of Pediatrics, Reutlingen, Germany
| | - Steven Dobrowolski
- Department of Pathology, University of Pittsburgh, School of Medicine, Pittsburgh, PA 15224, United States
| | - Daniela Berg
- Department of Neurology, University Hospital of Schleswig-Holstein, Kiel, Germany
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Ilgaz F, Ford S, O’Driscoll MF, MacDonald A. Adult PKU Clinics in the UK-Users' Experiences and Perspectives. Nutrients 2023; 15:4352. [PMID: 37892429 PMCID: PMC10610305 DOI: 10.3390/nu15204352] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 10/01/2023] [Accepted: 10/05/2023] [Indexed: 10/29/2023] Open
Abstract
Adults with PKU require life-long management, and ideally, their care should be in a specialised adult metabolic clinic. Their outcomes and co-morbidities have received much attention, but data are lacking on their experience, satisfaction and expectations about the care they receive. This survey reports the experiences and care adults with PKU receive from specialist metabolic clinics in the UK. The online survey developed by the UK NSPKU (National Society for Phenylketonuria), was placed on the NSPKU website from February 2021 to December 2022, and was completed by adults with PKU (≥18 years) or their carers/family members. Sixty-five adult PKU patients and 9 caregivers of adult patients completed the questionnaire (63% female in total). Only 32% of respondents were following a Phe-restricted diet with protein substitute intake as prescribed; the rest were partially adherent or not on dietary restrictions. Nineteen per cent (n = 14/74) had not been reviewed in clinic for two years. Half of the respondents (50%) described their experience in adult clinics as "good". Half of the patients were unable to contact their dietitians with questions or concerns, and only 24% considered that they received adequate support. Clinic reviews usually included anthropometric (82%) and dietary assessments (64%), discussion on management of PKU in daily life (78%) and a blood test (71%). Eighty-eight per cent reported they had at least one neurocognitive, mental health or behavioural co-morbidity but less than half of the patients reported an assessment on their neurocognitive functioning or mental health issues. Adult male patients appeared to have less detailed clinic review than females. Less than half (44%) of the respondents reported that they performed a blood spot for blood Phe at least monthly, but only 32% considered they had been informed about the risk of high Phe levels in adulthood. Although time, cost and stress related to travelling were barriers to a face-to-face review, more than 40% of patients had concerns about remote appointments. The frequency and extent of monitoring of adults with PKU, attending specialist adult services, were less than those specified by the PKU European guidelines. The care of women of reproductive age is prioritised over men. Adult metabolic health services require further attention, development and resources to provide a high standard and equitable service to patients with PKU.
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Affiliation(s)
- Fatma Ilgaz
- Department of Nutrition and Dietetics, Faculty of Health Sciences, Hacettepe University, 06100 Ankara, Turkey
| | - Suzanne Ford
- Southmead Hospital North Bristol Trust, Bristol BS10 5NB, UK;
- National Society for Phenylketonuria (NSPKU), Sheffield S12 9ET, UK
| | - Michael F. O’Driscoll
- Department of Adult Child & Midwifery, School of Health Social Care & Education, Middlesex University, London NW4 4BT, UK;
| | - Anita MacDonald
- Birmingham Children’s Hospital, Steelhouse Lane, Birmingham B4 6NH, UK;
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Charrière S, Maillot F, Bouée S, Douillard C, Jacob C, Schneider KM, Theil J, Arnoux JB. Health status and comorbidities of adult patients with phenylketonuria (PKU) in France with a focus on early-diagnosed patients - A nationwide study of health insurance claims data. Mol Genet Metab 2023; 139:107625. [PMID: 37329624 DOI: 10.1016/j.ymgme.2023.107625] [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: 01/05/2023] [Revised: 05/30/2023] [Accepted: 05/30/2023] [Indexed: 06/19/2023]
Abstract
BACKGROUND This study aimed at evaluating the health status and healthcare consumption of ≥16-year-old patients with phenylketonuria (PKU), with a focus on early-diagnosed patients. METHODS This retrospective observational study used health insurance claims data from the French SNDS (Système National des Données de Santé) database. Patients with PKU were identified between 2006 and 2018 by ICD-10 diagnosis codes E70.0 (classic PKU) or E70.1 (other causes of hyperphenylalaninemia). They were matched to controls by age, sex, and region. Patients with early-diagnosed PKU were defined as patients born after implementation of nationwide newborn screening in France in 1972. Outcomes were analyzed for the year 2018. RESULTS Overall, 3549 patients with PKU were identified on January 1st, 2018. Of those, 3469 patients could be matched to 17,170 controls without PKU. Of these patients, 2175 were at least 16 years old and suffered significantly more than controls from specific comorbidities of interest - osteoporosis (28.7% vs 19.8%, p < 0.0001), hypertension (20.9% vs 17.0%, p < 0.0001), hypercholesterolemia (12.8% vs 8.3%, p < 0.0001), diabetes (7.8% vs 4.7%, p < 0.0001), obesity (4.2% vs 1.3%, p < 0.0001), ischemic heart diseases (4.8% vs 2.0%, p < 0.0001), and depression (10.3% vs 8.2%, p = 0.0011). Prescriptions for many medications were also more frequent in patients with PKU than controls. Among ≥16-year-old patients, 1528 were categorized as early-diagnosed. Osteoporosis (0.3% vs 0.01%, p = 0.0035), chronic renal failure (0.6% vs 0.1%, p = 0.0020), hypertension (4.0% vs 2.7%, p = 0.0063), and obesity (2.5% vs 0.8%, p < 0.0001) were significantly more prevalent in early-diagnosed adult patients compared with matched controls. In total, 28.6% of ≥16-year-old patients with PKU and 40.4% of early-diagnosed patients with PKU received dietary amino-acid supplements. Sapropterin was prescribed to 5.0% and 7.0% patients, respectively. CONCLUSION The results indicate that PKU is associated with a significantly higher comorbidity risk along with increased pharmaceutical prescriptions in adulthood. The comorbidity burden is less distinct in early-diagnosed patients but still present. Few patients are treated specifically for PKU in adulthood. Healthcare of patients with PKU should include prevention and management of comorbidities and especially target PKU-specific treatment adherence and consistent care in specialized medical centers in adulthood.
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Affiliation(s)
- Sybil Charrière
- Hospices Civils de Lyon, Department of endocrinology, diabetologia, metabolic diseases and nutrition, Hôpital Louis Pradel, 69600 BRON, France. CarMen laboratory, INSERM, INRAE, Université Claude Bernard Lyon 1, 69310, Pierre Bénite, France.
| | - Francois Maillot
- Service de médecine interne, CHRU et Université de Tours, UMR INSERM 1253 « iBrain », Tours, France.
| | - Stéphane Bouée
- CEMKA, 43 boulevard du Maréchal Joffre, 92340, Bourg-La-Reine, France.
| | - Claire Douillard
- Service d'endocrinologie, diabétologie, métabolisme et nutrition, Centre de Référence des Maladies Héréditaires du Métabolisme, Hôpital Huriez, CHU de Lille, 59037 Lille, France.
| | | | | | - Julia Theil
- Xcenda GmbH, Lange Laube 31, 30159 Hannover, Germany.
| | - Jean-Baptiste Arnoux
- Centre de Référence des Maladies Héréditaires du Métabolisme, Hôpital Necker-Enfants Malades, APHP, 149 rue de Sèvres, 75015 Paris, France.
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Wada Y, Totsune E, Mikami-Saito Y, Kikuchi A, Miyata T, Kure S. A method for phenylalanine self-monitoring using phenylalanine ammonia-lyase and a pre-existing portable ammonia detection system. Mol Genet Metab Rep 2023; 35:100970. [PMID: 37020603 PMCID: PMC10068251 DOI: 10.1016/j.ymgmr.2023.100970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 03/15/2023] [Indexed: 03/29/2023] Open
Abstract
Phenylketonuria is an inborn error of phenylalanine metabolism caused by a phenylalanine hydroxylase deficiency. To prevent the occurrence of neurological symptoms and maternal complications resulting from phenylketonuria, patients must adhere to a strict diet therapy, tetrahydrobiopterin supplementation, or pegvaliase injection to maintain blood phenylalanine levels within a recommended range throughout their lives. Therefore, monitoring blood phenylalanine levels is necessary to determine the recent metabolic status of phenylalanine in patients with PKU; however, there are no available instruments for individuals to monitor their own blood phenylalanine levels using whole fingertip blood. We developed a phenylalanine monitoring system (designated as PheCheck) that included a pre-existing portable ammonia detection device and phenylalanine ammonia-lyase, which converts phenylalanine to trans-cinnamic acid and ammonia. This system was able to remove 86.7% ± 0.03% of the ammonia contained in fingertip blood and successfully reduce background ammonia levels. A good correlation was found between the estimated plasma phenylalanine levels detected by PheCheck and plasma phenylalanine levels detected by high-performance liquid chromatography (R2 0.97). The entire PheCheck process for measuring blood phenylalanine takes only 20 min. PheCheck can lay the foundation for home phenylalanine monitoring with high feasibility because all the components are easily accessible. Further studies with a more user-friendly PheCheck optimized for practice are needed to improve blood phenylalanine control, reduce the burden on patients and/or caregivers, and prevent the sequelae associated with phenylketonuria.
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Affiliation(s)
- Yoichi Wada
- Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan
- Corresponding author at: Department of Pediatrics, Tohoku University School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan.
| | - Eriko Totsune
- Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan
| | - Yasuko Mikami-Saito
- Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan
| | - Atsuo Kikuchi
- Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan
| | - Toshio Miyata
- United Centers for Advanced Research and Translational Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Shigeo Kure
- Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan
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De Giorgi A, Nardecchia F, Manti F, Campistol J, Leuzzi V. Neuroimaging in early-treated phenylketonuria patients and clinical outcome: A systematic review. Mol Genet Metab 2023; 139:107588. [PMID: 37149991 DOI: 10.1016/j.ymgme.2023.107588] [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: 02/16/2023] [Revised: 04/20/2023] [Accepted: 04/21/2023] [Indexed: 05/09/2023]
Abstract
Lacking direct neuropathological data, neuroimaging exploration has become the most powerful tool to give insight into pathophysiological alterations of early-treated PKU (ETPKU) patients. We conducted a systematic review of neuroimaging studies in ETPKU patients to explore 1) the occurrence of consistent neuroimaging alterations; 2) the relationship between them and neurological and cognitive disorders; 3) the contribution of neuroimaging in the insight of neuropathological background of ETPKU subjects; 4) whether brain neuroimaging may provide additional information in the monitoring of the disease course. Thirty-eight studies met the inclusion criteria for the full-text review, including morphological T1/T2 sequences, diffusion brain imaging (DWI/DTI) studies, brain MRI volumetric, functional neuroimaging studies, neurotransmission and brain energetic imaging studies. Non-progressive brain white matter changes were the most frequent and precocious alterations. As confirmed in hundreds of young adults with ETPKU, they affect over 90% of ETPKU patients. Consistent correlations are emerging between microstructural alteration (as detected by DWI/DTI) and metabolic control, which have also been confirmed in a few interventional trials. Volumetric studies detected later and less consistent cortical and subcortical grey matter alterations, which seem to be influenced by the patient's age and metabolic control. The few functional neuroimaging studies so far showed preliminary but interesting data about cortical activation patterns, skill performance, and brain connectivity. Further research is mandatory in these more complex areas. Recurrent methodological limitations include restricted sample sizes concerning the clinical variability of the disease, large age-range, variable measures of metabolic control, and prevalence of cross-sectional rather than longitudinal interventional studies.
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Affiliation(s)
- Agnese De Giorgi
- Division of Child Neurology and Infantile Psychiatry, Department of Human Neurosciences, Sapienza University of Rome, Rome, Italy
| | - Francesca Nardecchia
- Division of Child Neurology and Infantile Psychiatry, Department of Human Neurosciences, Sapienza University of Rome, Rome, Italy
| | - Filippo Manti
- Division of Child Neurology and Infantile Psychiatry, Department of Human Neurosciences, Sapienza University of Rome, Rome, Italy
| | - Jaume Campistol
- Neuropaediatrics Department, Hospital Sant Joan de Déu, University of Barcelona, Barcelona, Spain
| | - Vincenzo Leuzzi
- Division of Child Neurology and Infantile Psychiatry, Department of Human Neurosciences, Sapienza University of Rome, Rome, Italy.
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Burgunder JM. Mechanisms underlying phenotypic variation in neurogenetic disorders. Nat Rev Neurol 2023:10.1038/s41582-023-00811-4. [PMID: 37202496 DOI: 10.1038/s41582-023-00811-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/12/2023] [Indexed: 05/20/2023]
Abstract
Neurological diseases associated with pathogenic variants in a specific gene, or even with a specific pathogenic variant, can show profound phenotypic variation with regard to symptom presentation, age at onset and disease course. Highlighting examples from a range of neurogenetic disorders, this Review explores emerging mechanisms that are involved in this variability, including environmental, genetic and epigenetic factors that influence the expressivity and penetrance of pathogenic variants. Environmental factors, some of which can potentially be modified to prevent disease, include trauma, stress and metabolic changes. Dynamic patterns of pathogenic variants might explain some of the phenotypic variations, for example, in the case of disorders caused by DNA repeat expansions such as Huntington disease (HD). An important role for modifier genes has also been identified in some neurogenetic disorders, including HD, spinocerebellar ataxia and X-linked dystonia-parkinsonism. In other disorders, such as spastic paraplegia, the basis for most of the phenotypic variability remains unclear. Epigenetic factors have been implicated in disorders such as SGCE-related myoclonus-dystonia and HD. Knowledge of the mechanisms underlying phenotypic variation is already starting to influence management strategies and clinical trials for neurogenetic disorders.
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9
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Wang MW, Wu CJ, Zhang ZQ. Neurological and imaging phenotypes of adults with untreated phenylketonuria: new cases and literature review. J Neurol 2023:10.1007/s00415-023-11760-9. [PMID: 37162580 DOI: 10.1007/s00415-023-11760-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 05/02/2023] [Accepted: 05/04/2023] [Indexed: 05/11/2023]
Abstract
OBJECTIVES Phenylketonuria (PKU) is the most prevalent congenital disease of amino acid metabolism. Neurological manifestations usually complicate PKU in untreated adult patients. This study describes neurological and imaging phenotypes of adult patients with untreated PKU. METHODS We investigated a cohort of 320 unrelated adult patients with suspected genetic leukoencephalopathies using whole-exome sequencing (WES). We analyzed the phenotypic features of adult PKU patients in our cohort and summarized cases reported in the literature. RESULTS We identified 10 patients in our cohort and 12 patients in the literature, who presented with neurological manifestations and were diagnosed with PKU in adulthood. Approximately 60% of these patients had onset of clinical features in adulthood. The most common neurological symptoms of patients presenting in adulthood were cognitive disturbance and spastic paralysis, followed by vision loss, cerebellar ataxia, weakness of limbs, and seizure. This differed from that of patients presenting with PKU features in childhood, who consistently had mental retardation with various neurological complications emerging during a broad age range. Imaging findings were similar between patients presenting with clinical features in childhood compared with adulthood, comprising symmetric periventricular white matter hyperintense on T2-weighted imaging and diffusion-weighted imaging predominantly in the parietal and occipital lobes. Also, normal brain imaging and diffuse leukoencephalopathies were observed in both patient groups. CONCLUSION PKU with clinical features presenting in adulthood is an atypical subtype and should be considered during diagnosis of adults with neurological symptoms and leukoencephalopathy. DWI seems to be most helpful to distinguish patients with PKU. Additionally, we demonstrate that PKU constitutes a part (3.1%) of adult genetic leukoencephalopathies.
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Affiliation(s)
- Meng-Wen Wang
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, 350005, China
| | - Chu-Jun Wu
- Department of Neurology, Beijing Tiantan Hospital, National Clinical Research Center for Neurological Diseases, Capital Medical University, No.119 South 4Th Ring West Road, Fengtai District, Beijing, 100070, China
- China National Clinical Research Center for Neurological Diseases, Beijing, 100070, China
| | - Zai-Qiang Zhang
- Department of Neurology, Beijing Tiantan Hospital, National Clinical Research Center for Neurological Diseases, Capital Medical University, No.119 South 4Th Ring West Road, Fengtai District, Beijing, 100070, China.
- China National Clinical Research Center for Neurological Diseases, Beijing, 100070, China.
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10
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Merkel M, Berg D, Brüggemann N, Classen J, Mainka T, Zittel S, Muntau AC. Characterisation and differential diagnosis of neurological complications in adults with phenylketonuria: literature review and expert opinion. J Neurol 2023:10.1007/s00415-023-11703-4. [PMID: 37081197 DOI: 10.1007/s00415-023-11703-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 03/31/2023] [Accepted: 04/01/2023] [Indexed: 04/22/2023]
Abstract
OBJECTIVE Phenylketonuria (PKU) is a rare inherited metabolic disorder characterised by elevated phenylalanine (Phe) concentrations that can exert neurotoxic effects if untreated or upon treatment discontinuation. This systematic review supported by expert opinion aims to raise awareness among the neurological community on neurological complications experienced by adults with PKU (AwPKU). METHODS The PubMed database was searched for articles on neurological signs and symptoms in AwPKU published before March 2022. In addition, two virtual advisory boards were held with a panel of seven neurologists and two metabolic physicians from Germany and Austria. Findings are supported by three illustrative patient cases. RESULTS Thirty-nine articles were included. Despite early diagnosis and treatment, neurological signs and symptoms (e.g. ataxia, brisk tendon reflexes, tremor, visual impairment) can emerge in adulthood, especially if treatment has been discontinued after childhood. In PKU, late-onset neurological deficits often co-occur with cognitive impairment and psychiatric symptoms, all of which can be completely or partially reversed through resumption of treatment. CONCLUSION Ideally, neurologists should be part of the PKU multidisciplinary team, either to bring lost to follow-up patients back to clinic or to manage symptoms in referred patients, considering that symptoms are often reversible upon regaining metabolic control. The current findings have been combined in a leaflet that will be disseminated among neurologists in Germany and Austria to create awareness.
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Affiliation(s)
- Martin Merkel
- Endokrinologikum Hamburg, Lornsenstraße 6, 22767, Hamburg, Germany.
- Asklepios Campus Hamburg, Semmelweis University, Hamburg, Germany.
| | - Daniela Berg
- Department of Neurology, Christian-Albrechts University, Kiel, Germany
| | | | - Joseph Classen
- Department of Neurology, Leipzig University Medical Center, Leipzig, Germany
| | - Tina Mainka
- Department of Neurology, Charité University Medicine Berlin, Berlin, Germany
- Berlin Institute of Health at Charité Universitätsmedizin Berlin, BIH Biomedical Innovation Academy, BIH Charité Clinician Scientist Program, Berlin, Germany
| | - Simone Zittel
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ania C Muntau
- University Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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11
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Mele S, Martelli F, Lin J, Kanca O, Christodoulou J, Bellen HJ, Piper MDW, Johnson TK. Drosophila as a diet discovery tool for treating amino acid disorders. Trends Endocrinol Metab 2023; 34:85-105. [PMID: 36567227 DOI: 10.1016/j.tem.2022.12.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 12/06/2022] [Indexed: 12/24/2022]
Abstract
Amino acid disorders (AADs) are a large group of rare inherited conditions that collectively impact one in 6500 live births, often resulting in rapid neurological decline and death during infancy. For several AADs, including phenylketonuria, dietary modification prevents physiological deterioration and ameliorates symptoms. Despite this remarkable potential for treatment success, dietary therapy for most AADs remains largely unexplored. Although animal models have provided novel insights into AAD mechanisms, few have been used for therapeutic diet discovery. Here, we find that of all the animal models, Drosophila is particularly well suited for nutrigenomic disease modelling, having amino acid pathways conserved with humans, exceptional genetic tractability, and the unique availability of a synthetic customisable diet.
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Affiliation(s)
- Sarah Mele
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - Felipe Martelli
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - Jiayi Lin
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - Oguz Kanca
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Duncan Neurological Research Institute of Texas Children's Hospital, Baylor College of Medicine, Houston, TX, USA
| | - John Christodoulou
- Murdoch Children's Research Institute, Parkville, Australia; Department of Paediatrics, University of Melbourne, Melbourne, Victoria 3052, Australia
| | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Duncan Neurological Research Institute of Texas Children's Hospital, Baylor College of Medicine, Houston, TX, USA
| | - Matthew D W Piper
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia.
| | - Travis K Johnson
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia.
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12
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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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13
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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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14
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Manti F, Caviglia S, Cazzorla C, Dicintio A, Pilotto A, Burlina AP. Expert opinion of an Italian working group on the assessment of cognitive, psychological, and neurological outcomes in pediatric, adolescent, and adult patients with phenylketonuria. Orphanet J Rare Dis 2022; 17:443. [PMID: 36544165 PMCID: PMC9769037 DOI: 10.1186/s13023-022-02488-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 08/15/2022] [Indexed: 12/24/2022] Open
Abstract
Phenylketonuria (PKU) is an inherited metabolic disease characterized by a defective conversion of phenylalanine (Phe) to tyrosine, potentially leading to Phe accumulation in the brain. Dietary restriction since birth has led to normal cognitive development. However, PKU patients can still develop cognitive or behavioral abnormalities and subtle neurological deficits. Despite the increasing evidence in the field, the assessment of neurocognitive, psychopathological, and neurological follow-up of PKU patients at different ages is still debated. The high interindividual variability in the cognitive outcome of PKU patients makes the specificity of the neurocognitive and behavioral assessment extremely challenging. In the present paper, a multidisciplinary panel of Italian PKU experts discussed different tools available for cognitive, psychopathological, and neurological assessment at different ages based on the existing literature and daily clinical practice. This study aims to provide evidence and a real-life-based framework for a specific clinical assessment of pediatric, adolescent, and adult patients affected by PKU.
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Affiliation(s)
- Filippo Manti
- grid.7841.aUnit of Child Neurology and Psychiatry, Department of Human Neuroscience, University of Rome La Sapienza, Rome, Italy
| | - Stefania Caviglia
- grid.414125.70000 0001 0727 6809Unit of Clinical Psychology, Department of Neurosciences, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Chiara Cazzorla
- grid.411474.30000 0004 1760 2630Division of Inborn Metabolic Diseases, Department of Pediatrics, University Hospital, Padua, Italy
| | - Annamaria Dicintio
- grid.488556.2Department of Metabolic Diseases and Clinical Genetics, Giovanni XXIII Children Hospital, Azienda Ospedaliero-Universitaria Consorziale Policlinico, 70126 Bari, Italy
| | - Andrea Pilotto
- grid.7637.50000000417571846Neurology Unit, Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy
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15
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Li H, Yang H, Li M, Liang L, Zhu H, Chen A, Qian H. Mild hyperphenylalaninemia (hpa) presenting as orthostatic tremor: a case report. BMC Neurol 2022; 22:409. [PMCID: PMC9635091 DOI: 10.1186/s12883-022-02946-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 10/27/2022] [Indexed: 11/06/2022] Open
Abstract
Abstract
Background
Orthostatic tremor (OT) is a type of postural tremor of the lower extremities that has not been described in either phenylketonuria (PKU) or hyperphenylalaninemia (HPA). Because little is known about the clinical features and therapeutic responses of OT in mild HPA, we describe a mild HPA patient who presented with OT as an initial symptom.
Case presentation
A 22-year-old male was admitted for bilateral leg tremor while standing, with symptom onset eight months prior. One month before admission, the tremor disappeared in the left leg but persisted in the right leg. Electromyography recorded from the right gastrocnemius revealed a 6–8 Hz tremor, which appeared when the patient was standing and disappeared when he was resting or walking. Blood screening showed a phenylalanine/tyrosine ratio of 2.06 and a phenylalanine level of 140 μmol/L. Urine metabolic screening was negative. Whole-exome sequencing confirmed the presence of a compound heterozygous mutation, c.158G > A and c.728G > A, in phenylalanine hydroxylase (PAH) gene. After three months of levodopa/benserazide tablets (250 mg, tid) and a low-phenylalanine diet treatment, the tremor disappeared.
Conclusions
Young-onset mild HPA is a relatively rare autosomal recessive metabolic disease, and slow OT is a rare clinical feature. Metabolic screening and genetic testing are the keys to early diagnosis and treatment. For adolescents and young adults, appropriate medication and long-term dietary therapy remain important treatments. This case expanded the disease spectrum of slow OT.
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16
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Khaksari K, Chen WL, Gropman AL. Review of Applications of Near-Infrared Spectroscopy in Two Rare Disorders with Executive and Neurological Dysfunction: UCD and PKU. Genes (Basel) 2022; 13:genes13101690. [PMID: 36292574 PMCID: PMC9602148 DOI: 10.3390/genes13101690] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 09/12/2022] [Accepted: 09/16/2022] [Indexed: 11/16/2022] Open
Abstract
Studying rare diseases, particularly those with neurological dysfunction, is a challenge to researchers and healthcare professionals due to their complexity and small population with geographical dispersion. Universal and standardized biomarkers generated by tools such as functional neuroimaging have been forged to collect baseline data as well as treatment effects. However, the cost and heavily infrastructural requirement of those technologies have substantially limited their availability. Thus, developing non-invasive, portable, and inexpensive modalities has become a major focus for both researchers and clinicians. When considering neurological disorders and diseases with executive dysfunction, EEG is the most convenient tool to obtain biomarkers which can correlate the objective severity and clinical observation of these conditions. However, studies have also shown that EEG biomarkers and clinical observations alone are not sensitive enough since not all the patients present classical phenotypical features or EEG evidence of dysfunction. This article reviews disorders, including two rare disorders with neurological dysfunction and the usefulness of functional near-infrared spectroscopy (fNIRS) as a non-invasive optical modality to obtain hemodynamic biomarkers of diseases and for screening and monitoring the disease.
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Affiliation(s)
- Kosar Khaksari
- Division of Neurogenetics and Developmental Pediatrics, Children’s National Health System, Washington, DC 20010, USA
- Correspondence:
| | - Wei-Liang Chen
- School of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Andrea L. Gropman
- Division of Neurogenetics and Developmental Pediatrics, Children’s National Health System, Washington, DC 20010, USA
- Department of Neurology, George Washington University, Washington, DC 20052, USA
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17
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Elhawary NA, AlJahdali IA, Abumansour IS, Elhawary EN, Gaboon N, Dandini M, Madkhali A, Alosaimi W, Alzahrani A, Aljohani F, Melibary EM, Kensara OA. Genetic etiology and clinical challenges of phenylketonuria. Hum Genomics 2022; 16:22. [PMID: 35854334 PMCID: PMC9295449 DOI: 10.1186/s40246-022-00398-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 07/08/2022] [Indexed: 02/08/2023] Open
Abstract
This review discusses the epidemiology, pathophysiology, genetic etiology, and management of phenylketonuria (PKU). PKU, an autosomal recessive disease, is an inborn error of phenylalanine (Phe) metabolism caused by pathogenic variants in the phenylalanine hydroxylase (PAH) gene. The prevalence of PKU varies widely among ethnicities and geographic regions, affecting approximately 1 in 24,000 individuals worldwide. Deficiency in the PAH enzyme or, in rare cases, the cofactor tetrahydrobiopterin results in high blood Phe concentrations, causing brain dysfunction. Untreated PKU, also known as PAH deficiency, results in severe and irreversible intellectual disability, epilepsy, behavioral disorders, and clinical features such as acquired microcephaly, seizures, psychological signs, and generalized hypopigmentation of skin (including hair and eyes). Severe phenotypes are classic PKU, and less severe forms of PAH deficiency are moderate PKU, mild PKU, mild hyperphenylalaninaemia (HPA), or benign HPA. Early diagnosis and intervention must start shortly after birth to prevent major cognitive and neurological effects. Dietary treatment, including natural protein restriction and Phe-free supplements, must be used to maintain blood Phe concentrations of 120-360 μmol/L throughout the life span. Additional treatments include the casein glycomacropeptide (GMP), which contains very limited aromatic amino acids and may improve immunological function, and large neutral amino acid (LNAA) supplementation to prevent plasma Phe transport into the brain. The synthetic BH4 analog, sapropterin hydrochloride (i.e., Kuvan®, BioMarin), is another potential treatment that activates residual PAH, thus decreasing Phe concentrations in the blood of PKU patients. Moreover, daily subcutaneous injection of pegylated Phe ammonia-lyase (i.e., pegvaliase; PALYNZIQ®, BioMarin) has promised gene therapy in recent clinical trials, and mRNA approaches are also being studied.
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Affiliation(s)
- Nasser A. Elhawary
- grid.412832.e0000 0000 9137 6644Department of Medical Genetics, College of Medicine, Umm Al-Qura University, P.O. Box 57543, Mecca, 21955 Saudi Arabia
| | - Imad A. AlJahdali
- grid.412832.e0000 0000 9137 6644Department of Community Medicine, College of Medicine, Umm Al-Qura University, P.O. Box 57543, Mecca, 21955 Saudi Arabia
| | - Iman S. Abumansour
- grid.412832.e0000 0000 9137 6644Department of Medical Genetics, College of Medicine, Umm Al-Qura University, P.O. Box 57543, Mecca, 21955 Saudi Arabia
| | - Ezzeldin N. Elhawary
- grid.123047.30000000103590315Faculty of Medicine, MS Genomic Medicine Program, University of Southampton, Southampton General Hospital, Southampton, UK
| | - Nagwa Gaboon
- grid.7269.a0000 0004 0621 1570Department of Clinical Genetics, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Mohammed Dandini
- Department of Laboratory and Blood Bank, Maternity and Children Hospital, Mecca, Saudi Arabia
| | - Abdulelah Madkhali
- grid.415254.30000 0004 1790 7311Department of Pathology and Laboratory Medicine, King Abdulaziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia
| | - Wafaa Alosaimi
- Department of Hematology, Maternity and Children Hospital, Mecca, Saudi Arabia
| | - Abdulmajeed Alzahrani
- Department of Laboratory and Blood Bank at Maternity and Children Hospital, Mecca, Saudi Arabia
| | - Fawzia Aljohani
- Department of Pediatric Clinics, Maternity and Children Hospital, King Salman Medical City, Madinah, Saudi Arabia
| | - Ehab M. Melibary
- grid.412832.e0000 0000 9137 6644Department of Medical Genetics, College of Medicine, Umm Al-Qura University, P.O. Box 57543, Mecca, 21955 Saudi Arabia
| | - Osama A. Kensara
- grid.412832.e0000 0000 9137 6644Department of Clinical Nutrition, Faculty of Applied Medical Sciences, Umm Al-Qura University, Jeddah, Saudi Arabia
- Department of Biochemistry, Batterjee Medical College, Jeddah, Saudi Arabia
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18
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Kanufre V, Almeida MF, Barbosa CS, Carmona C, Bandeira A, Martins E, Rocha S, Guimas A, Ribeiro R, MacDonald A, Pinto A, Rocha JC. Metabolic Control of Patients with Phenylketonuria in a Portuguese Metabolic Centre Comparing Three Different Recommendations. Nutrients 2021; 13:3118. [PMID: 34578995 PMCID: PMC8469656 DOI: 10.3390/nu13093118] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 08/28/2021] [Accepted: 09/01/2021] [Indexed: 11/16/2022] Open
Abstract
Blood phenylalanine (Phe) is used as the primary marker to evaluate metabolic control. Our study aimed to describe the metabolic control of patients with phenylketonuria (PKU) comparing three different treatment recommendations (European guidelines/US guidelines/Portuguese consensus). This was a retrospective, observational, single centre study in patients with PKU collecting data on blood Phe levels from 2017. Nutritional intake data and sapropterin (BH4) prescription were collected at the last appointment of 2017. The final sample studied included 87 patients (48% females) [13 hyperphenylalaninemia; 47 mild PKU; 27 classical PKU] with a median age of 18 y (range: 1-36 y). The median number of blood Phe measurements for patients was 21 (range: 6-89). In patients aged < 12 y, the median blood Phe level was 300 μmol/L (range 168-480) and 474 μmol/L (range 156-1194) for patients ≥ 12 y. Overall, a median of 83% of blood Phe levels were within the European PKU guidelines target range. In patients aged ≥ 12 years, there was a higher median % of blood Phe levels within the European PKU guidelines target range (≥12 y: 84% vs. <12 y: 56%). In children < 12 y with classical PKU (n = 2), only 34% of blood Phe levels were within target range for all 3 guidelines and 49% with mild PKU (n = 11). Girls had better control than boys (89% vs. 66% median Phe levels within European Guidelines). Although it is clear that 50% or more patients were unable to achieve acceptable metabolic control on current treatment options, a globally agreed upper Phe target associated with optimal outcomes for age groups is necessary. More studies need to examine how clinics with dissimilar resources, different therapeutic Phe targets and frequency of monitoring relate to metabolic control.
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Affiliation(s)
- Viviane Kanufre
- Centro de Genética Médica, Centro Hospitalar Universitário do Porto (CHUPorto), 4099-028 Porto, Portugal; (V.K.); (M.F.A.); catarina-s-@hotmail.com (C.S.B.); (C.C.)
- Centro de Referência na Área de Doenças Hereditárias do Metabolismo, Centro Hospitalar Universitário do Porto-CHUPorto, 4099-001 Porto, Portugal; (A.B.); (E.M.); (S.R.); (A.G.); (R.R.)
- Núcleo de Ações e Pesquisa em Apoio Diagnóstico (NUPAD), School of Medicine, Federal University of Minas Gerais (UFMG), Avenida Professor Alfredo Balena, 190, Belo Horizonte 30130-100, Brazil
- Hospital das Clínicas, UFMG, Avenida Professor Alfredo Balena, 110, Santa Efigênia, Belo Horizonte 30130-100, Brazil
| | - Manuela Ferreira Almeida
- Centro de Genética Médica, Centro Hospitalar Universitário do Porto (CHUPorto), 4099-028 Porto, Portugal; (V.K.); (M.F.A.); catarina-s-@hotmail.com (C.S.B.); (C.C.)
- Centro de Referência na Área de Doenças Hereditárias do Metabolismo, Centro Hospitalar Universitário do Porto-CHUPorto, 4099-001 Porto, Portugal; (A.B.); (E.M.); (S.R.); (A.G.); (R.R.)
- Unit for Multidisciplinary Research in Biomedicine, Abel Salazar Institute of Biomedical Sciences, University of Porto-UMIB/ICBAS/UP, 4050-313 Porto, Portugal
| | - Catarina Sousa Barbosa
- Centro de Genética Médica, Centro Hospitalar Universitário do Porto (CHUPorto), 4099-028 Porto, Portugal; (V.K.); (M.F.A.); catarina-s-@hotmail.com (C.S.B.); (C.C.)
- Centro de Referência na Área de Doenças Hereditárias do Metabolismo, Centro Hospitalar Universitário do Porto-CHUPorto, 4099-001 Porto, Portugal; (A.B.); (E.M.); (S.R.); (A.G.); (R.R.)
| | - Carla Carmona
- Centro de Genética Médica, Centro Hospitalar Universitário do Porto (CHUPorto), 4099-028 Porto, Portugal; (V.K.); (M.F.A.); catarina-s-@hotmail.com (C.S.B.); (C.C.)
- Centro de Referência na Área de Doenças Hereditárias do Metabolismo, Centro Hospitalar Universitário do Porto-CHUPorto, 4099-001 Porto, Portugal; (A.B.); (E.M.); (S.R.); (A.G.); (R.R.)
- Unit for Multidisciplinary Research in Biomedicine, Abel Salazar Institute of Biomedical Sciences, University of Porto-UMIB/ICBAS/UP, 4050-313 Porto, Portugal
| | - Anabela Bandeira
- Centro de Referência na Área de Doenças Hereditárias do Metabolismo, Centro Hospitalar Universitário do Porto-CHUPorto, 4099-001 Porto, Portugal; (A.B.); (E.M.); (S.R.); (A.G.); (R.R.)
| | - Esmeralda Martins
- Centro de Referência na Área de Doenças Hereditárias do Metabolismo, Centro Hospitalar Universitário do Porto-CHUPorto, 4099-001 Porto, Portugal; (A.B.); (E.M.); (S.R.); (A.G.); (R.R.)
- Unit for Multidisciplinary Research in Biomedicine, Abel Salazar Institute of Biomedical Sciences, University of Porto-UMIB/ICBAS/UP, 4050-313 Porto, Portugal
| | - Sara Rocha
- Centro de Referência na Área de Doenças Hereditárias do Metabolismo, Centro Hospitalar Universitário do Porto-CHUPorto, 4099-001 Porto, Portugal; (A.B.); (E.M.); (S.R.); (A.G.); (R.R.)
| | - Arlindo Guimas
- Centro de Referência na Área de Doenças Hereditárias do Metabolismo, Centro Hospitalar Universitário do Porto-CHUPorto, 4099-001 Porto, Portugal; (A.B.); (E.M.); (S.R.); (A.G.); (R.R.)
| | - Rosa Ribeiro
- Centro de Referência na Área de Doenças Hereditárias do Metabolismo, Centro Hospitalar Universitário do Porto-CHUPorto, 4099-001 Porto, Portugal; (A.B.); (E.M.); (S.R.); (A.G.); (R.R.)
| | - Anita MacDonald
- Birmingham Women’s and Children’s Hospital, Birmingham B4 6NH, UK; (A.M.); (A.P.)
| | - Alex Pinto
- Birmingham Women’s and Children’s Hospital, Birmingham B4 6NH, UK; (A.M.); (A.P.)
| | - Júlio César Rocha
- Centro de Genética Médica, Centro Hospitalar Universitário do Porto (CHUPorto), 4099-028 Porto, Portugal; (V.K.); (M.F.A.); catarina-s-@hotmail.com (C.S.B.); (C.C.)
- Centro de Referência na Área de Doenças Hereditárias do Metabolismo, Centro Hospitalar Universitário do Porto-CHUPorto, 4099-001 Porto, Portugal; (A.B.); (E.M.); (S.R.); (A.G.); (R.R.)
- Nutrition & Metabolism, NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Campo Mártires da Pátria, 130, 1169-056 Lisbon, Portugal
- Centre for Health Technology and Services Research (CINTESIS), 4200-450 Porto, Portugal
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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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Krämer J. Sustaining benefits of nutritional therapy in young adults with phenylketonuria - A 2 year prospective study. Mol Genet Metab Rep 2020; 22:100573. [PMID: 32099818 PMCID: PMC7026618 DOI: 10.1016/j.ymgmr.2020.100573] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 01/31/2020] [Indexed: 01/09/2023] Open
Abstract
Introduction Phenylketonuria (PKU) is an inborn error of metabolism, which is caused by a deficiency in the enzyme phenylalanine hydroxylase (PAH). Life-long Phe-free diet impairs quality of life, especially in adolescents and young adults which take responsibility over their diet and therapy from their parents, but expect freedom in daily routine. Methods and results 105 patients with PKU were screened for eligibility for participating in this study. Data of 21 patients with genetic predictive value (GPV) ≤5 and age between 14 and 30 years were included in the analysis. Mean age of the study population was 22.6 ± 7.5 years, 8 patients (38%) were female. At baseline, structured counselling by a professional nutrionist was performed. Mean Phe-level at baseline was 926 ± 432 μmol/l, after six months Phe-levels were significantly reduced to 709 ± 314 μmol/l (p = .039), in total 4 additional patients (38% of the population) reached values within the therapeutic goal. After 12, 18 and 24 months, mean Phe-level elevated significantly to initial level (869 ± 427 μmol/l; p = .311). Mean daily intake of natural protein at baseline was 32.3 ± 24.3 g per day. There was a significant decrease after 6 months (26.9 ± 18.8 g/day; p = .049) and 12 months (25.9 ± 16.2 g/day; p = .30) compared to baseline. Values at 18 months (27.5 ± 9.2 g/day; p = .26) and 24 months (35.0 ± 22.3 g/day; p = .87) did not differ. Mean daily supplementation of Phe-free amino acids was 26.2 ± 19.2 g per day. In all follow-up examinations a significant increase compared to baseline values was calculated (42.4 ± 17.6 g/day after 6 moths (p = .028), 52.1 ± 29.9 g/day after 12 months (p ≤.01), 38.7 ± 20.3 g/day after 18 months (p < .01) and 39.3 ± 21.9 g/day after 24 months (p = .014)). At baseline, mean total protein intake (natural protein plus supplements) was 0.97 ± 0.42 g per kg body weight (g/kgBW). After 24 months the protein intake was within recommended levels. (1.23 ± 0.33 g/kgKB; p = .013). After 24 months, plasma Vitamin B12 increased to 424.8 ± 176.9 pg/ml (baseline 368.6 ± 205.6 pg/ml; p = .049) and Vitamin D increased to 30.4 ± 9.9 ng/ml (baseline 24.5 ± 10.1 ng/ml; p = .06). Conclusion Counselling by a professional nutrionist in young adults with PKU has clear short-term effects on plasma Phe-levels. Easy applicable therapeutic recommendations, as additional intake of amino acid supplement, are well tolerated and result in strict therapy adherence up to 24 months. Apart from that, the effects on Phe-levels seem only to sustain for about 6 months. More frequent nutritional counselling, i.e. at least two times per year, is recommended to preserve positive effects on Phe-levels. Lack of Vitamin B12 and Vitamin D still are common in PKU patients, but not necessarily need to be substituted. They can effectively be equalized by a well-balanced diet within 24 months.
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Affiliation(s)
- Johannes Krämer
- Corresponding author at: University of Ulm, Division of Pediatric Neurology and Inborn Errors of Metabolism, Eythstr. 24, 89075 Ulm, Germany.
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Krämer J. Case-control study about the acceptance of Pegvaliase in Phenylketonuria. Mol Genet Metab Rep 2020; 22:100557. [PMID: 31956507 PMCID: PMC6957785 DOI: 10.1016/j.ymgmr.2019.100557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 12/21/2019] [Indexed: 10/25/2022] Open
Abstract
Introduction Pegvaliase is a novel enzyme substitution therapy approved by the European Drug Administration (EDA) in May 2019 for the treatment of Phenylketonuria (PKU) in adults and children ≥16 years of age. The pegylated phenylalanine ammonia lyase is isolated from bacteria and therefore provokes multifarious immunogenic reactions. Thus, the selection of the right patient for a potential harmful treatment is essential for patient's contentedness and long-term therapy compliance. Methods and results 101 patients with PKU were screened for eligibility for an additional treatment with Pegvaliase. 51 patients were included in the study, 26 received a structural information about the new treatment for in mean 43 ± 12 min and clinical data and plasma Phe-levels were assessed. After 4 weeks of consideration the willing of treatment initiation as well as reasons for denial are registered. 7 patients (27%) concluded in beginning of treatment. Phe-level in this (acceptance) group were higher (1180 ± 231 μmol/l) compared to the denial group (930 ± 278 μmol/l, p = .01). After 4 weeks Phe-levels in the acceptance group remained stable (1264 ± 311 μmol/l, p = .26) while Phe-levels in the denial group decreased (779 ± 226 μmol/l, p < .01). Main reasons for denial of therapy were fear of adverse effects (47%), no need for additional treatment (26%) and the subcutaneous way of application (21%). Conclusion PKU patients have reservations against an invasive subcutaneous treatment for their disease. This is mainly caused by the form of application by syringe and the potential harmful side effects. Only less than one-third of the patients in our cohort are willing to start treatment. Besides that, most PKU patients seem to have untapped potential for self-contained reduction of Phe-levels only by being focused on their diet.
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Affiliation(s)
- Johannes Krämer
- Division of Inborn Errors of Metabolism, Children's Hospital, University of Ulm, Ulm, Germany.,Division of Pediatric Neurology, Children's Hospital, University of Ulm, Ulm, Germany
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