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Sestito S, Brodosi L, Ferraro S, Carella R, De Giovanni D, Mita D, Moretti M, Moricca MT, Concolino D, Tummolo A. Benefits of a prolonged-release amino acid mixture in four pregnant women with phenylketonuria. Nutr Health 2024:2601060241248522. [PMID: 38651794 DOI: 10.1177/02601060241248522] [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: 04/25/2024]
Abstract
Background: Maternal phenylketonuria (mPKU) is a pathologic condition occurring in the fetus of a mother with PKU that is caused by prolonged elevated intrauterine blood phenylalanine (Phe) levels, which can lead to congenital abnormalities and mental retardation of newborns. Management of PKU during pregnancy can be challenging as protein substitutes may exacerbate nausea, vomiting, and gastrointestinal symptoms. Aim: To report the successful management of four PKU pregnant women. Methods: The patients were administered with prolonged-release amino acid supplementation and were recommended to follow a strict diet. Blood Phe concentration, adherence to diet, and occurrence of adverse events were monitored. Results: All patients achieved safe levels of blood Phe concentration (120-360 µmol/L) since preconception and during pregnancy (mean Phe concentration values of 143.34 ± 137.59, 226.48 ± 194.57, 186.68 ± 133.67, and 187.47 ± 42.59 µmol/L). During the first trimester of pregnancy, all patients manifested gastrointestinal symptoms such as nausea, gastrointestinal reflux, and abdominal bloating, which were managed by either changing protein substitute or extending the time window between different meals and amino acid mixtures administration. The four women continued their pregnancies without experiencing further complications and delivered neonates with normal growth parameters and no malformations. Conclusion: Findings of this case series suggest that the intake of a prolonged-release amino acid mixture in granules is well tolerated by pregnant PKU patients, eventually leading to good metabolic control and fetal growth within normal ranges.
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Affiliation(s)
- Simona Sestito
- UOC Pediatria Specialistica e Malattie Rare, Università Magna Graecia, Catanzaro, Italy
| | - Lucia Brodosi
- SSD Nutrizione Clinica e Metabolismo - IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Stefania Ferraro
- UOC Pediatria Specialistica e Malattie Rare, Università Magna Graecia, Catanzaro, Italy
| | - Rosa Carella
- Department of Metabolic Diseases, Clinical Genetics and Diabetology, Giovanni XXIII Children Hospital, Azienda Ospedaliero-Universitaria Consorziale, Bari, Italy
| | - Donatella De Giovanni
- Department of Metabolic Diseases, Clinical Genetics and Diabetology, Giovanni XXIII Children Hospital, Azienda Ospedaliero-Universitaria Consorziale, Bari, Italy
| | - Dorina Mita
- SSD Nutrizione Clinica e Metabolismo - IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Michele Moretti
- SSD Nutrizione Clinica e Metabolismo - IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Maria Teresa Moricca
- UOC Pediatria Specialistica e Malattie Rare, Università Magna Graecia, Catanzaro, Italy
| | - Daniela Concolino
- UOC Pediatria Specialistica e Malattie Rare, Università Magna Graecia, Catanzaro, Italy
| | - Albina Tummolo
- Department of Metabolic Diseases, Clinical Genetics and Diabetology, Giovanni XXIII Children Hospital, Azienda Ospedaliero-Universitaria Consorziale, Bari, Italy
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Ahring K, Bélanger-Quintana A, Burlina A, Giżewska M, Maillot F, Muntau A, Roscher A, MacDonald A. Management of phenylketonuria in European PKU centres remains heterogeneous. Mol Genet Metab 2024; 141:108120. [PMID: 38159545 DOI: 10.1016/j.ymgme.2023.108120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 12/19/2023] [Accepted: 12/19/2023] [Indexed: 01/03/2024]
Abstract
Phenylketonuria (PKU) is a genetic disorder that follows an autosomal recessive inheritance pattern. Dietary treatment is the cornerstone of therapy and is based on natural protein restriction, Phe-free L-amino acid supplements (protein substitutes) and low protein foods. The aim of this project was to collect information about the clinical management of patients with PKU, focusing on understudied or unresolved issues such as blood phenylalanine (Phe) fluctuations and clinical symptoms, particularly gastro intestinal (GI) discomfort and sleep problems. The survey consisted of 10 open-ended and 12 multiple-choice questions that collected information about size of the PKU population in each center, the center's clinical practices and the outcomes observed by the center concerning adherence, clinical and biochemical abnormalities and clinical symptoms (GI and sleep). The questionnaire was sent to 72 experts from metabolic centers in 11 European countries. Thirty-three centers answered. The results of this survey provide information about the clinical practice in different age groups, concentrating on dietary tolerance, treatment adherence, and metabolic control. All the centers prescribed a Phe-restricted diet, with Phe-free/low Phe protein substitutes and low protein foods. Daily doses given of protein substitutes varied from 1 to 5, with adherence to the prescribed amounts decreasing with increasing age. Respondents identified that improvement in the flavor, taste, volume and smell of protein substitutes may improve adherence. Finally, the survey showed that clinical symptoms, such as GI discomfort and sleep problems occur in patients with PKU but are not systematically evaluated. Twenty-four-hour Phe fluctuations were not routinely assessed. The results highlight a strong heterogeneity of approach to management despite international PKU guidelines. More clinical attention should be given to gastrointestinal and sleep problems in PKU.
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Affiliation(s)
| | - Amaya Bélanger-Quintana
- Pediatrics Service, Congenital Errors of Metabolism Unit (CSUR and MetabERN), Ramon and Cajal University Hospital, CIBER-ER, Ramon and Cajal Institute for Health Research (IRYCIS), Spain
| | - Alberto Burlina
- Division of Inherited Metabolic Diseases, Reference Centre Expanded Newborn Screening, University Hospital Padova, 35129 Padova, Italy
| | - Maria Giżewska
- Department of Pediatrics, Endocrinology, Diabetology, Metabolic Diseases and Cardiology of the Developmental Age, Pomeranian Medical University in Szczecin, Szczecin, Poland
| | - Francois Maillot
- CHRU De Tours, Service of Internal Medicine, Reference center for inherited metabolic diseases, Tours' University, INSERM U1253, Labex MabImprove, Tours, France
| | - Ania Muntau
- University Children's Hospital, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Anne Roscher
- Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria
| | - Anita MacDonald
- Birmingham Children's Hospital, Steelhouse Lane, Birmingham B4 6NH, UK.
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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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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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Manta-Vogli PD, Dotsikas Y, Loukas YL, Schulpis KH. The phenylketonuria patient: A recent dietetic therapeutic approach. Nutr Neurosci 2020; 23:628-639. [PMID: 30359206 DOI: 10.1080/1028415x.2018.1538196] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Phenylalanine hydroxylase (PAH) deficiency, commonly named phenylketonuria (PKU) is a disorder of phenylalanine (Phe) metabolism inherited with an autosomal recessive trait. It is characterized by high blood and cerebral Phe levels, resulting in intellectual disabilities, seizures, etc. Early diagnosis and treatment of the patients prevent major neuro-cognitive deficits. Treatment consists of a lifelong restriction of Phe intake, combined with the supplementation of special medical foods, such as Amino Acid medical food (AA-mf), enriched in tyrosine (Tyr) and other amino acids and nutrients to avoid nutritional deficits. Developmental and neurocognitive outcomes for patients, however, remain suboptimal, especially when adherence to the demanding diet is poor. Additions to treatment include new, more palatable foods, based on Glycomacropeptide that contains limited amounts of Phe, the administration of large neutral amino acids to prevent phenylalanine entry into the brain and tetrahydrobiopterin cofactor capable of increasing residual PAH activity. Moreover, further efforts are underway to develop an oral therapy containing phenylalanine ammonia-lyase. Nutritional support of PKU future mothers (maternal PKU) is also discussed. This review aims to summarize the current literature on new PKU treatment strategies.
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Affiliation(s)
- Penelope D Manta-Vogli
- Department of Clinical Nutrition & Dietetics Agia Sofia Children's Hospital, Athens, Greece
| | - Yannis Dotsikas
- Department of Pharmacy, Laboratory of Pharm. Analysis, National and Kapodestrian University of Athens, Panepistimiopolis Zographou, GR 157 71, Athens, Greece
| | - Yannis L Loukas
- Department of Pharmacy, Laboratory of Pharm. Analysis, National and Kapodestrian University of Athens, Panepistimiopolis Zographou, GR 157 71, Athens, Greece
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6
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Zhu T, Ye J, Han L, Qiu W, Zhang H, Liang L, Gu X. The Predictive Value of Genetic Analyses in the Diagnosis of Tetrahydrobiopterin (BH4)-Responsiveness in Chinese Phenylalanine Hydroxylase Deficiency Patients. Sci Rep 2017; 7:6762. [PMID: 28754886 PMCID: PMC5533732 DOI: 10.1038/s41598-017-06462-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 06/13/2017] [Indexed: 11/23/2022] Open
Abstract
Molecular characterization of PAH deficiency has been proven essential in establishing treatment options. We examine the diagnostic accuracy of two genetic assays to predict BH4 responsiveness: to determine whether the AV sum test or mutation-status assessment test can obviate the need for BH4 loading in Chinese patients. The overall predicted response in 346 patients was 31.65% by the AV sum test and 25.43% by the other assay; both percentages were lower than 51.06% derived from loading results in 94 patients. Responders were compound heterozygotes with definite BH4 responsive mutations, while non-responders had null/null ones; some consistently with specific mutations and genotypes. The sensitivity and specificity of the assays were 81.1% and 92.5% for the AV sum, and 82.9%, 97.3% for the other. An AV sum cutoff >2 has a positive predictive value (PPV) of 90.9%, while the presence of at least one BH4 responsive mutation has a PPV of 97.1%. The two approaches showed good concordance. Our data confirmed that the mutation-status assessment has a higher diagnostic accuracy in predicting response for Chinese patients than the AV sum test. BH4-responsiveness may be predicted or excluded from patients' molecular characteristics to some extent, thus some patients may avoid the initial loading.
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Affiliation(s)
- Tianwen Zhu
- Department of Neonatal Medicine, Xin-Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jun Ye
- Department of Endocrinology and Genetic Metabolism, Xin-Hua Hospital, Shanghai Institute of Pediatric Research Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lianshu Han
- Department of Endocrinology and Genetic Metabolism, Xin-Hua Hospital, Shanghai Institute of Pediatric Research Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Wenjuan Qiu
- Department of Endocrinology and Genetic Metabolism, Xin-Hua Hospital, Shanghai Institute of Pediatric Research Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Huiwen Zhang
- Department of Endocrinology and Genetic Metabolism, Xin-Hua Hospital, Shanghai Institute of Pediatric Research Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lili Liang
- Department of Endocrinology and Genetic Metabolism, Xin-Hua Hospital, Shanghai Institute of Pediatric Research Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xuefan Gu
- Department of Endocrinology and Genetic Metabolism, Xin-Hua Hospital, Shanghai Institute of Pediatric Research Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.
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7
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Hawks Z, Shimony J, Rutlin J, Grange DK, Christ SE, White DA. Pretreatment cognitive and neural differences between sapropterin dihydrochloride responders and non-responders with phenylketonuria. Mol Genet Metab Rep 2017; 12:8-13. [PMID: 28271047 PMCID: PMC5323508 DOI: 10.1016/j.ymgmr.2017.01.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 01/28/2017] [Indexed: 12/02/2022] Open
Abstract
Sapropterin dihydrochloride (BH4) reduces phenylalanine (Phe) levels and improves white matter integrity in a subset of individuals with phenylketonuria (PKU) known as “responders.” Although prior research has identified biochemical and genotypic differences between BH4 responders and non-responders, cognitive and neural differences remain largely unexplored. To this end, we compared intelligence and white matter integrity prior to treatment with BH4 in 13 subsequent BH4 responders with PKU, 16 subsequent BH4 non-responders with PKU, and 12 healthy controls. Results indicated poorer intelligence and white matter integrity in non-responders compared to responders prior to treatment. In addition, poorer white matter integrity was associated with greater variability in Phe across the lifetime in non-responders but not in responders. These results underscore the importance of considering PKU as a multi-faceted, multi-dimensional disorder and point to the need for additional research to delineate characteristics that predict response to treatment with BH4.
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Affiliation(s)
- Zoë Hawks
- Department of Psychological and Brain Sciences, Campus Box 1125, Washington University, St. Louis, MO 63130, USA
| | - Joshua Shimony
- Mallinckrodt Institute of Radiology, Campus Box 8131, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Jerrel Rutlin
- Mallinckrodt Institute of Radiology, Campus Box 8131, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Dorothy K Grange
- Department of Pediatrics, Campus Box 8116, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Shawn E Christ
- Department of Psychological Sciences, 210 McAlester Hall, University of Missouri, Columbia, MO 65211, USA
| | - Desirée A White
- Department of Psychological and Brain Sciences, Campus Box 1125, Washington University, St. Louis, MO 63130, USA; Department of Pediatrics, Campus Box 8116, Washington University School of Medicine, St. Louis, MO 63110, USA
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8
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Rapid quantitative method for the detection of phenylalanine and tyrosine in human plasma using pillar array columns and gradient elution. Amino Acids 2016; 48:1731-5. [DOI: 10.1007/s00726-016-2248-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Accepted: 04/29/2016] [Indexed: 11/25/2022]
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9
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Aldámiz-Echevarría L, Llarena M, Bueno MA, Dalmau J, Vitoria I, Fernández-Marmiesse A, Andrade F, Blasco J, Alcalde C, Gil D, García MC, González-Lamuño D, Ruiz M, Ruiz MA, Peña-Quintana L, González D, Sánchez-Valverde F, Desviat LR, Pérez B, Couce ML. Molecular epidemiology, genotype-phenotype correlation and BH4 responsiveness in Spanish patients with phenylketonuria. J Hum Genet 2016; 61:731-44. [PMID: 27121329 DOI: 10.1038/jhg.2016.38] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 03/16/2016] [Accepted: 03/24/2016] [Indexed: 01/26/2023]
Abstract
Phenylketonuria (PKU), the most common inborn error of amino acid metabolism, is caused by mutations in the phenylalanine-4-hydroxylase (PAH) gene. This study aimed to assess the genotype-phenotype correlation in the PKU Spanish population and the usefulness in establishing genotype-based predictions of BH4 responsiveness in our population. It involved the molecular characterization of 411 Spanish PKU patients: mild hyperphenylalaninemia non-treated (mild HPA-NT) (34%), mild HPA (8.8%), mild-moderate (20.7%) and classic (36.5%) PKU. BH4 responsiveness was evaluated using a 6R-BH4 loading test. We assessed genotype-phenotype associations and genotype-BH4 responsiveness in our population according to literature and classification of the mutations. The mutational spectrum analysis showed 116 distinct mutations, most missense (70.7%) and located in the catalytic domain (62.9%). The most prevalent mutations were c.1066-11G>A (9.7%), p.Val388Met (6.6%) and p.Arg261Gln (6.3%). Three novel mutations (c.61-13del9, p.Ile283Val and p.Gly148Val) were reported. Although good genotype-phenotype correlation was observed, there was no exact correlation for some genotypes. Among the patients monitored for the 6R-BH4 loading test: 102 were responders (87, carried either one or two BH4-responsive alleles) and 194 non-responders (50, had two non-responsive mutations). More discrepancies were observed in non-responders. Our data reveal a great genetic heterogeneity in our population. Genotype is quite a good predictor of phenotype and BH4 responsiveness, which is relevant for patient management, treatment and follow-up.
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Affiliation(s)
- Luis Aldámiz-Echevarría
- Unit of Metabolism, Cruces University Hospital, BioCruces Health Research Institute, GCV-CIBER de Enfermedades Raras (CIBERER), Plaza de Cruces s/n, Barakaldo, Spain
| | - Marta Llarena
- Unit of Metabolism, Cruces University Hospital, BioCruces Health Research Institute, GCV-CIBER de Enfermedades Raras (CIBERER), Plaza de Cruces s/n, Barakaldo, Spain
| | - María A Bueno
- Metabolic Disorders, Dietetics and Nutrition Unit, Virgen del Rocío University Hospital, Manuel Siurot Avenue s/n, Sevilla, Spain
| | - Jaime Dalmau
- Nutrition and Metabolopathologies Unit, La Fe University Hospital, Bulevar Sur s/n, Valencia, Spain
| | - Isidro Vitoria
- Nutrition and Metabolopathologies Unit, La Fe University Hospital, Bulevar Sur s/n, Valencia, Spain
| | - Ana Fernández-Marmiesse
- Unit of Diagnosis and Treatment of Congenital Metabolic Diseases, Department of Pediatrics, Hospital Clínico Universitario de Santiago de Compostela, CIBERER, Health Research Institute of Santiago de Compostela (IDIS), A Choupana, s/n, Santiago de Compostela, A Coruña, Spain
| | - Fernando Andrade
- Unit of Metabolism, Cruces University Hospital, BioCruces Health Research Institute, GCV-CIBER de Enfermedades Raras (CIBERER), Plaza de Cruces s/n, Barakaldo, Spain
| | - Javier Blasco
- Gastroenterology, Hepatology and Child Nutrition Unit, Carlos Haya University Hospital, Avda. Arroyo de los Ángeles s/n, Málaga, Spain
| | - Carlos Alcalde
- Paediatrics Unit, Río Hortega University Hospital, Valladolid, Spain
| | - David Gil
- Gastroenterology Unit, Virgen de la Arrixaca University Hospital, Ctra. Madrid-Cartagena s/n, El Palmar, Murcia, Spain
| | - María C García
- Metabolic Pathologies Unit, Miguel Servet University Hospital, Zaragoza, Spain
| | | | - Mónica Ruiz
- Paediatrics Unit, Nuestra Señora de la Candelaria University Hospital, Santa Cruz de Tenerife, Spain
| | - María A Ruiz
- Metabolic Pathologies and Neuropaediatrics Unit, Son Espases University Hospital, Palma de Mallorca, Spain
| | - Luis Peña-Quintana
- Paediatric Gastroenterology, Hepatology and Nutrition Unit, Mother and Child Hospital Complex, Avda. Marítima del Sur s/n, Las Palmas de Gran Canaria, Spain
| | - David González
- Metabolic Pathologies Unit, Maternal and Child Hospital, Badajoz, Spain
| | - Felix Sánchez-Valverde
- Gastroenterology and Paediatric Nutrition Unit, Virgen del Camino Hospital, Pamplona, Spain
| | - Lourdes R Desviat
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular Severo Ochoa CSIC-UAM, CIBERER, IdiPaz, Madrid, Spain
| | - Belen Pérez
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular Severo Ochoa CSIC-UAM, CIBERER, IdiPaz, Madrid, Spain
| | - María L Couce
- Unit of Diagnosis and Treatment of Congenital Metabolic Diseases, Department of Pediatrics, Hospital Clínico Universitario de Santiago de Compostela, CIBERER, Health Research Institute of Santiago de Compostela (IDIS), A Choupana, s/n, Santiago de Compostela, A Coruña, Spain
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10
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Thiele AG, Rohde C, Mütze U, Arelin M, Ceglarek U, Thiery J, Baerwald C, Kiess W, Beblo S. The challenge of long-term tetrahydrobiopterin (BH4) therapy in phenylketonuria: Effects on metabolic control, nutritional habits and nutrient supply. Mol Genet Metab Rep 2015; 4:62-7. [PMID: 26937412 PMCID: PMC4750587 DOI: 10.1016/j.ymgmr.2015.07.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 07/13/2015] [Accepted: 07/13/2015] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND AND AIMS BH4-sensitive phenylketonuria (PKU) patients relax their phenylalanine (Phe) restricted diet due to increased Phe tolerance, while keeping dried blood Phe concentrations with in the therapeutic range. We aimed to investigate metabolic control, eating habits and nutrient supply under long-term BH4-therapy. PATIENTS AND METHODS Retrospective analysis of mean dried blood Phe concentrations and their variability, food and nutrient intake in BH4-sensitive patients (n = 8, 3f, age 6.0-16.6 y) under classical dietary treatment for one year and during the three years after initiation of BH4. RESULTS Phe concentrations of BH4-sensitve PKU patients remained within therapeutic range throughout the observation period, independent of therapeutic regime. Under BH4, Phe tolerance increased significantly (493.2 ± 161.8 mg/d under classical diet vs 2021.93 ± 897.4 mg/d two years under BH4; P = 0.004). Variability of Phe concentrations remained unchanged (mean SD; P = 1.000). Patients adjust their food choice and significantly increased their intake of cereals, potatoes, dairy products and meat (P = 0.019, P = 0.016, P = 0.016 and P = 0.016, respectively). Under diet changes after implementation of BH4 a drop in micronutrient intake (vitamin D, folic acid, iron, calcium, iodine) could be revealed (P = 0.005, P < 0.001, P = 0.004, P = 0.001, P = 0.003, respectively). CONCLUSIONS BH4-sensitive PKU patients can achieve good metabolic control under an adjuvant BH4- or a BH4 monotherapy. The liberalized diet under BH4 seems to jeopardize the quality of patients' nutrition, and these patients require close follow-up and special nutrition education to minimize the risk for imbalanced diet and nutrient deficiencies.
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Affiliation(s)
- Alena G. Thiele
- Hospital for Children and Adolescents, Centre for Pediatric Research Leipzig (CPL), Department of Women and Child Health, University Hospitals, University of Leipzig, Liebigstraße 20 a, 04103 Leipzig, Germany
| | - Carmen Rohde
- Hospital for Children and Adolescents, Centre for Pediatric Research Leipzig (CPL), Department of Women and Child Health, University Hospitals, University of Leipzig, Liebigstraße 20 a, 04103 Leipzig, Germany
| | - Ulrike Mütze
- Hospital for Children and Adolescents, Centre for Pediatric Research Leipzig (CPL), Department of Women and Child Health, University Hospitals, University of Leipzig, Liebigstraße 20 a, 04103 Leipzig, Germany
| | - Maria Arelin
- Hospital for Children and Adolescents, Centre for Pediatric Research Leipzig (CPL), Department of Women and Child Health, University Hospitals, University of Leipzig, Liebigstraße 20 a, 04103 Leipzig, Germany
| | - Uta Ceglarek
- Institute of Laboratory Medicine, Clinical Chemistry and Molecular Diagnostics, University of Leipzig, Liebigstraße 27, 04103 Leipzig, Germany
| | - Joachim Thiery
- Institute of Laboratory Medicine, Clinical Chemistry and Molecular Diagnostics, University of Leipzig, Liebigstraße 27, 04103 Leipzig, Germany
| | - Christoph Baerwald
- Department of Internal Medicine, University Hospitals, University of Leipzig, Liebigstraße 20, 04103 Leipzig, Germany
| | - Wieland Kiess
- Hospital for Children and Adolescents, Centre for Pediatric Research Leipzig (CPL), Department of Women and Child Health, University Hospitals, University of Leipzig, Liebigstraße 20 a, 04103 Leipzig, Germany
| | - Skadi Beblo
- Hospital for Children and Adolescents, Centre for Pediatric Research Leipzig (CPL), Department of Women and Child Health, University Hospitals, University of Leipzig, Liebigstraße 20 a, 04103 Leipzig, Germany
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11
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Aldámiz-Echevarría L, Bueno MA, Couce ML, Lage S, Dalmau J, Vitoria I, Llarena M, Andrade F, Blasco J, Alcalde C, Gil D, García MC, González-Lamuño D, Ruiz M, Ruiz MA, Peña-Quintana L, González D, Sánchez-Valverde F. 6R-tetrahydrobiopterin treated PKU patients below 4 years of age: Physical outcomes, nutrition and genotype. Mol Genet Metab 2015; 115:10-6. [PMID: 25882749 DOI: 10.1016/j.ymgme.2015.03.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 03/24/2015] [Accepted: 03/24/2015] [Indexed: 11/21/2022]
Abstract
BACKGROUND AND AIMS Phenylalanine-restricted diets have proven effective in treating phenylketonuria. However, such diets have occasionally been reported to hinder normal development. Our study aimed to assess whether treating 0-4-year-old phenylketonuric patients with 6R-tetrahydrobiopterin might prevent growth retardation later in life. METHODS We conducted a longitudinal retrospective study which examined anthropometric characteristics of phenylketonuric patients on 6R-tetrahydrobiopterin therapy (22 subjects), and compared them with a group of phenylketonuric patients on protein-restricted diets (44 subjects). Nutritional issues were also considered. We further explored possible relationships between mutations in the PAH gene, BH4 responsiveness and growth outcome. RESULTS No significant growth improvements were observed in either the group on 6R-tetrahydrobiopterin treatment (height Z-score: initial= -0.57 ± 1.54; final=-0.52 ± 1.29; BMI Z-score: initial=0.17 ± 1.05; final=0.18 ± 1.00) or the diet-only group (height Z-score: initial=-0.92 ± 0.96; final= -0.78 ± 1.08; BMI Z-score: initial=0.17 ± 0.97; final=-0.07 ± 1.03) over the 1-year observation period. Furthermore, we found no significant differences (p>0.05) between the two groups at any of the time points considered (0, 6 and 12 months). Patients on 6R-tetrahydrobiopterin increased their phenylalanine intake (from 49.1 [25.6-60.3] to 56.5 [39.8-68.3] mgkg(-1)day(-1)) and natural protein intake (from 1.0 [0.8-1.7] to 1.5 [1.0-1.8] g kg(-1)day(-1)), and some patients managed to adopt normal diets. Higher phenylalanine and natural protein intakes were positively correlated with better physical outcomes in the diet-only group (p<0.05). No correlation was found between patient genotype and physical outcomes, results being similar regardless of the nutritional approach used. We did not detect any side effects due to 6R-tetrahydrobiopterin administration. CONCLUSIONS Our study indicates that treating 0-4-year-old phenylketonuric patients with 6R-tetrahydrobiopterin is safe. However, poor developmental outcomes were observed, despite increasing the intake of natural proteins. Genotype could be a valid predictor of tetrahydrobiopterin-responsiveness, since patients who carried the same genotype responded similarly to the 6R-tetrahydrobiopterin loading test. On the other hand, harbouring 6R-tetrahydrobiopterin responsive genotypes did not predispose patients to better physical outcomes.
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Affiliation(s)
- Luis Aldámiz-Echevarría
- Division of Metabolism, BioCruces Health Research Institute, CIBER de Enfermedades Raras (CIBERER), Plaza de Cruces 12, 48903, Barakaldo, Spain.
| | - María A Bueno
- Metabolic Disorders, Dietetics and Nutrition Unit, Virgen del Rocío University Hospital, Manuel Siurot Avenue s/n, 41013, Sevilla, Spain.
| | - María L Couce
- Unit of Diagnosis and Treatment of Congenital Metabolic Diseases, Neonatology Service, Department of Pediatrics. Hospital Clinico Universitario de Santiago de Compostela, CIBER de Enfermedades Raras (CIBERER), IDIS, Spain.
| | - Sergio Lage
- Division of Metabolism, BioCruces Health Research Institute, CIBER de Enfermedades Raras (CIBERER), Plaza de Cruces 12, 48903, Barakaldo, Spain.
| | - Jaime Dalmau
- Nutrition and Metabolopathologies Unit, La Fe University Hospital, Bulevar Sur s/n, 46026, Valencia, Spain.
| | - Isidro Vitoria
- Nutrition and Metabolopathologies Unit, La Fe University Hospital, Bulevar Sur s/n, 46026, Valencia, Spain.
| | - Marta Llarena
- Division of Metabolism, BioCruces Health Research Institute, CIBER de Enfermedades Raras (CIBERER), Plaza de Cruces 12, 48903, Barakaldo, Spain.
| | - Fernando Andrade
- Division of Metabolism, BioCruces Health Research Institute, CIBER de Enfermedades Raras (CIBERER), Plaza de Cruces 12, 48903, Barakaldo, Spain.
| | - Javier Blasco
- Gastroenterology, Hepatology and Child Nutrition Unit, Carlos Haya University Hospital, Avda. Arroyo de los Ángeles s/n, 29011, Málaga, Spain.
| | - Carlos Alcalde
- Paediatrics Unit, Río Hortega University Hospital, Calle Dulzaina 2, 47012, Valladolid, Spain.
| | - David Gil
- Gastroenterology Unit, Virgen de la Arrixaca University Hospital, Ctra. Madrid-Cartagena s/n, El Palmar, 30120, Murcia, Spain.
| | - María C García
- Metabolic Pathologies Unit, Miguel Servet University Hospital, Paseo de Isabel La Católica 1-3, 50009, Zaragoza, Spain.
| | - Domingo González-Lamuño
- Nephrology and Metabolism Unit, Marqués de Valdecilla University Hospital, Avda. Valdecilla 25, 39008, Santander, Spain.
| | - Mónica Ruiz
- Paediatrics Unit, Nuestra Señora de la Candelaria University Hospital, Carretera del Rosario 145, 38010, Santa Cruz de Tenerife, Spain.
| | - María A Ruiz
- Metabolic Pathologies and Neuropaediatrics Unit, Son Espases University Hospital, Carretera de Valldemossa 79, 07120, Palma de Mallorca, Spain.
| | - Luis Peña-Quintana
- Paediatric Gastroenterology, Hepatology and Nutrition Unit, Mother and Child Hospital Complex, Avda. Marítima del Sur s/n, 35016, Las Palmas de Gran Canaria, Spain.
| | - David González
- Metabolic Pathologies Unit, Maternal and Child Hospital, Calle de la Violeta 1, 06010, Badajoz, Spain.
| | - Felix Sánchez-Valverde
- Gastroenterology and Paediatric Nutrition Unit, Virgen del Camino Hospital, C/ De Irunlarrea 4, 31008, Pamplona, Spain.
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12
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Camp KM, Parisi MA, Acosta PB, Berry GT, Bilder DA, Blau N, Bodamer OA, Brosco JP, Brown CS, Burlina AB, Burton BK, Chang CS, Coates PM, Cunningham AC, Dobrowolski SF, Ferguson JH, Franklin TD, Frazier DM, Grange DK, Greene CL, Groft SC, Harding CO, Howell RR, Huntington KL, Hyatt-Knorr HD, Jevaji IP, Levy HL, Lichter-Konecki U, Lindegren ML, Lloyd-Puryear MA, Matalon K, MacDonald A, McPheeters ML, Mitchell JJ, Mofidi S, Moseley KD, Mueller CM, Mulberg AE, Nerurkar LS, Ogata BN, Pariser AR, Prasad S, Pridjian G, Rasmussen SA, Reddy UM, Rohr FJ, Singh RH, Sirrs SM, Stremer SE, Tagle DA, Thompson SM, Urv TK, Utz JR, van Spronsen F, Vockley J, Waisbren SE, Weglicki LS, White DA, Whitley CB, Wilfond BS, Yannicelli S, Young JM. Phenylketonuria Scientific Review Conference: state of the science and future research needs. Mol Genet Metab 2014; 112:87-122. [PMID: 24667081 DOI: 10.1016/j.ymgme.2014.02.013] [Citation(s) in RCA: 157] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 02/25/2014] [Accepted: 02/26/2014] [Indexed: 01/17/2023]
Abstract
New developments in the treatment and management of phenylketonuria (PKU) as well as advances in molecular testing have emerged since the National Institutes of Health 2000 PKU Consensus Statement was released. An NIH State-of-the-Science Conference was convened in 2012 to address new findings, particularly the use of the medication sapropterin to treat some individuals with PKU, and to develop a research agenda. Prior to the 2012 conference, five working groups of experts and public members met over a 1-year period. The working groups addressed the following: long-term outcomes and management across the lifespan; PKU and pregnancy; diet control and management; pharmacologic interventions; and molecular testing, new technologies, and epidemiologic considerations. In a parallel and independent activity, an Evidence-based Practice Center supported by the Agency for Healthcare Research and Quality conducted a systematic review of adjuvant treatments for PKU; its conclusions were presented at the conference. The conference included the findings of the working groups, panel discussions from industry and international perspectives, and presentations on topics such as emerging treatments for PKU, transitioning to adult care, and the U.S. Food and Drug Administration regulatory perspective. Over 85 experts participated in the conference through information gathering and/or as presenters during the conference, and they reached several important conclusions. The most serious neurological impairments in PKU are preventable with current dietary treatment approaches. However, a variety of more subtle physical, cognitive, and behavioral consequences of even well-controlled PKU are now recognized. The best outcomes in maternal PKU occur when blood phenylalanine (Phe) concentrations are maintained between 120 and 360 μmol/L before and during pregnancy. The dietary management treatment goal for individuals with PKU is a blood Phe concentration between 120 and 360 μmol/L. The use of genotype information in the newborn period may yield valuable insights about the severity of the condition for infants diagnosed before maximal Phe levels are achieved. While emerging and established genotype-phenotype correlations may transform our understanding of PKU, establishing correlations with intellectual outcomes is more challenging. Regarding the use of sapropterin in PKU, there are significant gaps in predicting response to treatment; at least half of those with PKU will have either minimal or no response. A coordinated approach to PKU treatment improves long-term outcomes for those with PKU and facilitates the conduct of research to improve diagnosis and treatment. New drugs that are safe, efficacious, and impact a larger proportion of individuals with PKU are needed. However, it is imperative that treatment guidelines and the decision processes for determining access to treatments be tied to a solid evidence base with rigorous standards for robust and consistent data collection. The process that preceded the PKU State-of-the-Science Conference, the conference itself, and the identification of a research agenda have facilitated the development of clinical practice guidelines by professional organizations and serve as a model for other inborn errors of metabolism.
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Affiliation(s)
- Kathryn M Camp
- Office of Dietary Supplements, National Institutes of Health, Bethesda, MD 20982, USA.
| | - Melissa A Parisi
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
| | | | - Gerard T Berry
- Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
| | - Deborah A Bilder
- Department of Psychiatry, University of Utah, Salt Lake City, UT 84108, USA.
| | - Nenad Blau
- University Children's Hospital, Heidelberg, Germany; University Children's Hospital, Zürich, Switzerland.
| | - Olaf A Bodamer
- University of Miami Miller School of Medicine, Miami, FL 33136, USA.
| | - Jeffrey P Brosco
- University of Miami Mailman Center for Child Development, Miami, FL 33101, USA.
| | | | | | - Barbara K Burton
- Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, IL 60611, USA.
| | - Christine S Chang
- Agency for Healthcare Research and Quality, Rockville, MD 20850, USA.
| | - Paul M Coates
- Office of Dietary Supplements, National Institutes of Health, Bethesda, MD 20982, USA.
| | - Amy C Cunningham
- Tulane University Medical School, Hayward Genetics Center, New Orleans, LA 70112, USA.
| | | | - John H Ferguson
- Office of Rare Diseases Research, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20982, USA.
| | | | | | - Dorothy K Grange
- Washington University School of Medicine, St. Louis Children's Hospital, St. Louis, MO 63110, USA.
| | - Carol L Greene
- University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | - Stephen C Groft
- Office of Rare Diseases Research, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20982, USA.
| | - Cary O Harding
- Oregon Health & Science University, Portland, OR 97239, USA.
| | - R Rodney Howell
- University of Miami Miller School of Medicine, Miami, FL 33136, USA.
| | | | - Henrietta D Hyatt-Knorr
- Office of Rare Diseases Research, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20982, USA.
| | - Indira P Jevaji
- Office of Research on Women's Health, National Institutes of Health, Bethesda, MD 20817, USA.
| | - Harvey L Levy
- Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
| | - Uta Lichter-Konecki
- George Washington University, Children's National Medical Center, Washington, DC 20010, USA.
| | | | | | | | | | - Melissa L McPheeters
- Vanderbilt Evidence-based Practice Center, Institute for Medicine and Public Health, Nashville, TN 37203, USA.
| | - John J Mitchell
- McGill University Health Center, Montreal, Quebec H3H 1P3, Canada.
| | - Shideh Mofidi
- Maria Fareri Children's Hospital of Westchester Medical Center, Valhalla, NY 10595, USA.
| | - Kathryn D Moseley
- University of Southern California Keck School of Medicine, Los Angeles, CA 90033, USA.
| | - Christine M Mueller
- Office of Orphan Products Development, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA.
| | - Andrew E Mulberg
- Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA.
| | - Lata S Nerurkar
- Office of Rare Diseases Research, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20982, USA.
| | - Beth N Ogata
- University of Washington, Seattle, WA 98195, USA.
| | - Anne R Pariser
- Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA.
| | - Suyash Prasad
- BioMarin Pharmaceutical Inc., San Rafael, CA 94901, USA.
| | - Gabriella Pridjian
- Tulane University Medical School, Hayward Genetics Center, New Orleans, LA 70112, USA.
| | | | - Uma M Reddy
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
| | | | | | - Sandra M Sirrs
- Vancouver General Hospital, University of British Columbia, Vancouver V5Z 1M9, Canada.
| | | | - Danilo A Tagle
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Susan M Thompson
- The Children's Hospital at Westmead, Sydney, NSW 2145, Australia.
| | - Tiina K Urv
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Jeanine R Utz
- University of Minnesota, Minneapolis, MN 55455, USA.
| | - Francjan van Spronsen
- University of Groningen, University Medical Center of Groningen, Beatrix Children's Hospital, Netherlands.
| | - Jerry Vockley
- University of Pittsburgh, Pittsburgh, PA 15224, USA.
| | - Susan E Waisbren
- Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
| | - Linda S Weglicki
- National Institute of Nursing Research, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Desirée A White
- Department of Psychology, Washington University, St. Louis, MO 63130, USA.
| | | | - Benjamin S Wilfond
- Seattle Children's Research Institute, University of Washington School of Medicine, Seattle, WA 98101, USA.
| | | | - Justin M Young
- The Young Face, Facial Plastic and Reconstructive Surgery, Cumming, GA 30041, USA.
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13
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Abstract
Phenylketonuria (PKU) is an inborn error of metabolism of the amino acid phenylalanine. It is an autosomal recessive disorder with a rate of incidence of 1 in 10,000 in Caucasian populations. Mutations in the phenylalanine hydroxylase (PAH) gene are the major cause of PKU, due to the loss of the catalytic activity of the enzyme product PAH. Newborn screening for PKU allows early intervention, avoiding irreparable neurological damage and intellectual disability that would arise from untreated PKU. The current primary treatment of PKU is the limitation of dietary protein intake, which in the long term may be associated with poor compliance in some cases and other health problems due to malnutrition. The only alternative therapy currently approved is the supplementation of BH4, the requisite co-factor of PAH, in the orally-available form of sapropterin dihydrochloride. This treatment is not universally available, and is only effective for a proportion (estimated 30%) of PKU patients. Research into novel therapies for PKU has taken many different approaches to address the lack of PAH activity at the core of this disorder: enzyme replacement via virus-mediated gene transfer, transplantation of donor liver and recombinant PAH protein, enzyme substitution using phenylalanine ammonia lyase (PAL) to provide an alternative pathway for the metabolism of phenylalanine, and restoration of native PAH activity using chemical chaperones and nonsense read-through agents. It is hoped that continuing efforts into these studies will translate into a significant improvement in the physical outcome, as well as quality of life, for patients with PKU.
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Affiliation(s)
- Gladys Ho
- 1 Genetic Metabolic Disorders Research Unit; 2 Disciplines of Paediatrics and Child Health and 3 Genetic Medicine, University of Sydney, Sydney, NSW, Australia ; 4 Genetic Metabolic Disorders Service, Western Sydney Genetics Program, Children's Hospital at Westmead, Sydney, NSW, Australia
| | - John Christodoulou
- 1 Genetic Metabolic Disorders Research Unit; 2 Disciplines of Paediatrics and Child Health and 3 Genetic Medicine, University of Sydney, Sydney, NSW, Australia ; 4 Genetic Metabolic Disorders Service, Western Sydney Genetics Program, Children's Hospital at Westmead, Sydney, NSW, Australia
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14
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Cleary M, Trefz F, Muntau AC, Feillet F, van Spronsen FJ, Burlina A, Bélanger-Quintana A, Giżewska M, Gasteyger C, Bettiol E, Blau N, MacDonald A. Fluctuations in phenylalanine concentrations in phenylketonuria: a review of possible relationships with outcomes. Mol Genet Metab 2013; 110:418-23. [PMID: 24090706 DOI: 10.1016/j.ymgme.2013.09.001] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 09/03/2013] [Indexed: 11/21/2022]
Abstract
Fluctuations in blood phenylalanine concentrations may be an important determinant of intellectual outcome in patients with early and continuously treated phenylketonuria (PKU). This review evaluates the studies on phenylalanine fluctuations, factors affecting fluctuations, and if stabilizing phenylalanine concentrations affects outcomes, particularly neurocognitive outcome. Electronic literature searches of Embase and PubMed were performed for English-language publications, and the bibliographies of identified publications were also searched. In patients with PKU, phenylalanine concentrations are highest in the morning. Factors that can affect phenylalanine fluctuations include age, diet, timing and dosing of protein substitute and energy intake, dietary adherence, phenylalanine hydroxylase genotype, changes in dietary phenylalanine intake and protein metabolism, illness, and growth rate. Even distribution of phenylalanine-free protein substitute intake throughout 24h may reduce blood phenylalanine fluctuations. Patients responsive to and treated with 6R-tetrahydrobiopterin seem to have less fluctuation in their blood phenylalanine concentrations than controls. An increase in blood phenylalanine concentration may result in increased brain and cerebrospinal fluid phenylalanine concentrations within hours. Although some evidence suggests that stabilization of blood phenylalanine concentrations may have benefits in patients with PKU, more studies are needed to distinguish the effects of blood phenylalanine fluctuations from those of poor metabolic control.
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Affiliation(s)
- Maureen Cleary
- Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK.
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15
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Lindegren ML, Krishnaswami S, Reimschisel T, Fonnesbeck C, Sathe NA, McPheeters ML. A Systematic Review of BH4 (Sapropterin) for the Adjuvant Treatment of Phenylketonuria. JIMD Rep 2012; 8:109-19. [PMID: 23430527 DOI: 10.1007/8904_2012_168] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Revised: 06/20/2012] [Accepted: 07/04/2012] [Indexed: 12/04/2022] Open
Abstract
CONTEXT Dietary management is the mainstay of effective treatment in PKU, but dietary restriction is difficult and additional treatment options are needed. OBJECTIVE To systematically review evidence regarding sapropterin (BH4) use as an adjunct to dietary restriction in individuals with PKU. DATA SOURCES Five databases including MEDLINE up to August 2011. STUDY SELECTION Two reviewers independently assessed studies against predetermined inclusion/exclusion criteria. DATA EXTRACTION Two reviewers independently extracted data regarding participant and intervention characteristics and outcomes and assigned overall quality and strength of evidence ratings based on predetermined criteria. RESULTS BH4 research includes two randomized controlled trials (RCTs) and three uncontrolled open-label trials. Phenylalanine (Phe) levels were reduced by at least 30 % in up to half of treated participants (32-50 %). In one RCT comparing placebo on likelihood of a 30 % reduction in Phe, 9 % of those on placebo achieved this effect, compared with 44 % of the treated group after 6 weeks. Phe tolerance and variability were improved in treated participants in studies assessing those outcomes. No comparative studies assessed long-term outcomes including cognitive effects, nutritional status, or quality of life. CONCLUSIONS Adjuvant pharmacologic therapy has the potential to support individuals in achieving optimal Phe levels. BH4 has been shown to reduce Phe levels in some individuals, with significantly greater reductions seen in treated versus placebo groups. The strength of the evidence is moderate for short-term effects on reducing Phe in a subset of initially BH4-responsive individuals, moderate for a lack of significant harms, low for longer-term effects on cognition, and insufficient for all other outcomes.
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Affiliation(s)
- Mary Lou Lindegren
- Division of General Pediatrics and Vanderbilt Institute for Global Health, Vanderbilt Medical Center, 2200 Children's Way, 8232 Doctors' Office Tower, Nashville, TN, 37232-9225, USA,
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16
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Cunningham A, Bausell H, Brown M, Chapman M, DeFouw K, Ernst S, McClure J, McCune H, O'Steen D, Pender A, Skrabal J, Wessel A, Jurecki E, Shediac R, Prasad S, Gillis J, Cederbaum S. Recommendations for the use of sapropterin in phenylketonuria. Mol Genet Metab 2012; 106:269-76. [PMID: 22575621 DOI: 10.1016/j.ymgme.2012.04.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Revised: 04/05/2012] [Accepted: 04/05/2012] [Indexed: 11/18/2022]
Abstract
Phenylketonuria (PKU) is an inherited disorder of phenylalanine (Phe) metabolism. Until recently, the only treatment for PKU was a Phe-restricted diet. Increasing evidence of suboptimal outcomes in diet-treated individuals, inconsistent PKU management practices, and the recent availability of tetrahydrobiopterin (BH(4)) therapy have fueled the need for new management and treatment recommendations for this metabolic disorder. BH(4), now available as sapropterin dihydrochloride (sapropterin), may offer the potential for improved metabolic control as well as enhanced dietary Phe tolerance in some PKU patients. A group of metabolic dietitians from North America convened in June 2011 to draft recommendations for the use of sapropterin therapy in PKU. Physicians with extensive experience in PKU management were invited at a later date to contribute to the development of these recommendations. Based on extensive clinical experience and current evidence, the present recommendations provide guidance from patient selection and determination of sapropterin response to the long-term management of patients on sapropterin therapy. Target Phe levels, nutritional adequacy, neurocognitive screening and adherence to treatment are addressed to optimize patient outcomes.
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17
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Blau N, Hennermann JB, Langenbeck U, Lichter-Konecki U. Diagnosis, classification, and genetics of phenylketonuria and tetrahydrobiopterin (BH4) deficiencies. Mol Genet Metab 2011; 104 Suppl:S2-9. [PMID: 21937252 DOI: 10.1016/j.ymgme.2011.08.017] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Revised: 08/17/2011] [Accepted: 08/17/2011] [Indexed: 11/29/2022]
Abstract
This article summarizes the present knowledge, recent developments, and common pitfalls in the diagnosis, classification, and genetics of hyperphenylalaninemia, including tetrahydrobiopterin (BH4) deficiency. It is a product of the recent workshop organized by the European Phenylketonuria Group in March 2011 in Lisbon, Portugal. Results of the workshop demonstrate that following newborn screening for phenylketonuria (PKU), using tandem mass-spectrometry, every newborn with even slightly elevated blood phenylalanine (Phe) levels needs to be screened for BH4 deficiency. Dried blood spots are the best sample for the simultaneous measurement of amino acids (phenylalanine and tyrosine), pterins (neopterin and biopterin), and dihydropteridine reductase activity from a single specimen. Following diagnosis, the patient's phenotype and individually tailored treatment should be established as soon as possible. Not only blood Phe levels, but also daily tolerance for dietary Phe and potential responsiveness to BH4 are part of the investigations. Efficiency testing with synthetic BH4 (sapropterin dihydrochloride) over several weeks should follow the initial 24-48-hour screening test with 20mg/kg/day BH4. The specific genotype, i.e. the combination of both PAH alleles of the patient, helps or facilitates to determine both the biochemical phenotype (severity of PKU) and the responsiveness to BH4. The rate of Phe metabolic disposal after Phe challenge may be an additional useful tool in the interpretation of phenotype-genotype correlation.
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Affiliation(s)
- Nenad Blau
- University Children's Hospital, Zürich, Switzerland.
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