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Scala I, Brodosi L, Rovelli V, Noto D, Burlina A. Management of patients with phenylketonuria (PKU) under enzyme replacement therapy: An Italian model (expert opinion). Mol Genet Metab Rep 2024; 39:101065. [PMID: 38425869 PMCID: PMC10899016 DOI: 10.1016/j.ymgmr.2024.101065] [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: 11/29/2023] [Revised: 02/14/2024] [Accepted: 02/15/2024] [Indexed: 03/02/2024] Open
Abstract
Objective Phenylketonuria (PKU) is a metabolic disorder necessitating lifelong management to prevent severe neurological impairments. This paper synthesises clinical practices from Italian specialist centres to delineate a unified approach for administering pegvaliase, a novel enzyme replacement therapy for PKU. Methods Virtual meetings convened in September 2022, gathering a steering committee (SC) of experts from five Italian centres specialising in PKU. The SC reviewed, and discussed clinical practices, and formulated recommendations for pegvaliase treatment. Results The SC outlined a comprehensive treatment roadmap for PKU management with pegvaliase, emphasising the importance of multidisciplinary care teams, patient selection, pre-treatment evaluation, and education. Recommendations include initial hospital-based pegvaliase administration, regular monitoring of phenylalanine and tyrosine levels, dietary adjustments, and management of adverse events. A consensus was reached on the need for a digital database to manage treatment plans and enhance communication between healthcare professionals and patients. Conclusion The expert panel's consensus highlights the complexity of PKU management and the necessity for a coordinated, patient-centred approach. The recommendations aim to standardise care across Italian centres and provide a framework for integrating pegvaliase therapy into clinical practice, potentially informing international guidelines. Further research is warranted to evaluate the long-term impact of these practices on patient outcomes and quality of life.
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Affiliation(s)
- Iris Scala
- Clinical Genetics Unit, Department of Maternal and Child Health, “Federico II” University Hospital, Naples, Italy
| | - Lucia Brodosi
- Department of Medical and Surgical Sciences, “Alma Mater” University, Sant'Orsola-Malpighi Hospital, Bologna, Italy
- Clinical Nutrition and Metabolism Unit, IRCCS AOUBO, Bologna, Italy
| | - Valentina Rovelli
- Clinical Department of Pediatrics, University of Milan, ASST Santi Paolo e Carlo, San Paolo Hospital, Milan, Italy
| | - Davide Noto
- Department of Health Promotion, Maternal and Child Health, Internal and Specialized Medicine of Excellence "G. D. Alessandro" (PROMISE), University of Palermo, Italy
| | - Alberto Burlina
- Division of Inborn Metabolic Diseases, Department of Diagnostic Services, University Hospital of Padua, Padua, Italy
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2
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Bier C, Dickey K, Bibb B, Crutcher A, Sponberg R, Chang R, Boyer M, Davis-Keppen L, Matthes C, Tharp M, Vice D, Cooney E, Morand M, Ray J, Lah M, McNutt M, Andersson HC. Outcomes in 14 live births resulting from Pegvaliase-treated pregnancies in PKU-affected females. Mol Genet Metab 2024; 141:108152. [PMID: 38367583 DOI: 10.1016/j.ymgme.2024.108152] [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: 12/10/2023] [Revised: 01/26/2024] [Accepted: 01/28/2024] [Indexed: 02/19/2024]
Abstract
BACKGROUND Adults with PKU have difficulty maintaining plasma phenylalanine (Phe) in the range that is safe for neurologic function. Elevated plasma Phe is a risk factor for congenital anomalies and developmental delay in offspring resulting from pregnancies with poor Phe control in women with PKU. Enzyme supplementation with pegvaliase allows adults with PKU to eat an unrestricted diet and have plasma Phe levels in a safe range for pregnancy but pegvaliase has not been approved for use in pregnant females with PKU. We report the results of chart review of 14 living offspring of females affected with PKU who were responsive to pegvaliase and chose to remain on pegvaliase throughout their pregnancy. METHODS Fourteen pregnancies (one triplet pregnancy) and their offspring were identified at eight PKU treatment centers and medical records from pregnancy and birth were submitted for this study. Institutional Review Board approval was obtained. Responses to a dataset were provided to a single center and analyzed. RESULTS Six females and eight males were born without congenital anomalies and all offspring had normal growth parameters. While mothers had preexisting comorbidities, no additional comorbidities were reported in the offspring. Four of eleven infants (excluding triplet pregnancies) were delivered preterm (36%), a higher rate than the general population (12%). A single first trimester (eight weeks) miscarriage in a 40y was not counted in this cohort of 14 live born infants. CONCLUSION This retrospective study suggests that pegvaliase is effective at maintaining safe maternal blood Phe levels during pregnancy without deleterious effects on mother or child. A tendency toward premature birth (4/11; 36%) is higher than expected.
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Affiliation(s)
- Caide Bier
- Hayward Genetics Center, Tulane School of Medicine, 1430 Tulane Ave, New Orleans, 70112, Louisiana, United States of America
| | - Kaelin Dickey
- Internal Medicine, Clinical Genetics, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390, United States of America
| | - Brittan Bibb
- Pediatrics, Pediatric Genetics and Metabolism, Kentucky College of Medicine, 740 S. Limestone St, Lexington, KY 40536-0298, United States of America
| | - Angela Crutcher
- Pediatrics, Pediatric Genetics and Metabolism, Kentucky College of Medicine, 740 S. Limestone St, Lexington, KY 40536-0298, United States of America
| | - Rebecca Sponberg
- Division of Metabolic Disorders, PSF, Childrens Hospital of Orange County, 1201 W La Veta Ave, Orange, CA 92868, United States of America
| | - Richard Chang
- Division of Metabolic Disorders, PSF, Childrens Hospital of Orange County, 1201 W La Veta Ave, Orange, CA 92868, United States of America
| | - Monica Boyer
- Division of Metabolic Disorders, PSF, Childrens Hospital of Orange County, 1201 W La Veta Ave, Orange, CA 92868, United States of America
| | - Laura Davis-Keppen
- Department of Medical Genetics, USD Sanford School of Medicine, Sanford Children's Specialty Clinic, routing #6410, 1600 W 22nd Street, Sioux Falls, SD 57117, United States of America
| | - Cindy Matthes
- Department of Medical Genetics, USD Sanford School of Medicine, Sanford Children's Specialty Clinic, routing #6410, 1600 W 22nd Street, Sioux Falls, SD 57117, United States of America
| | - Michelle Tharp
- Pediatrics, Medical Genetics, University of Mississippi, Medical Center, 2500 North State Street, Jackson, MS 39216, United States of America
| | - Danielle Vice
- Pediatrics, Medical Genetics and Metabolism, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555-0359, United States of America
| | - Erin Cooney
- Pediatrics, Medical Genetics and Metabolism, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555-0359, United States of America
| | - Megan Morand
- Pediatrics, Medical Genetics and Metabolism, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555-0359, United States of America
| | - Joseph Ray
- Pediatrics, Medical Genetics and Metabolism, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555-0359, United States of America
| | - Melissa Lah
- Indiana University School of Medicine/IUHP, Department of Medical and Molecular Genetics, Department of Pediatrics, 975 W. Walnut St, IB130, Indianapolis, IN 46202, United States of America
| | - Markey McNutt
- Internal Medicine, Clinical Genetics, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390, United States of America
| | - Hans C Andersson
- Hayward Genetics Center, Tulane School of Medicine, 1430 Tulane Ave, New Orleans, 70112, Louisiana, United States of America.
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3
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Rovelli V, Longo N. Phenylketonuria and the brain. Mol Genet Metab 2023; 139:107583. [PMID: 37105048 DOI: 10.1016/j.ymgme.2023.107583] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 04/14/2023] [Accepted: 04/14/2023] [Indexed: 04/29/2023]
Abstract
Classic phenylketonuria (PKU) is caused by defective activity of phenylalanine hydroxylase (PAH), the enzyme that coverts phenylalanine (Phe) to tyrosine. Toxic accumulation of phenylalanine and its metabolites, left untreated, affects brain development and function depending on the timing of exposure to elevated levels. The specific mechanisms of Phe-induced brain damage are not completely understood, but they correlate to phenylalanine levels and on the stage of brain growth. During fetal life, high levels of phenylalanine such as those seen in maternal PKU can result in microcephaly, neuronal loss and corpus callosum hypoplasia. Elevated phenylalanine levels during the first few years of life can cause acquired microcephaly, severe cognitive impairment and epilepsy, likely due to the impairment of synaptogenesis. During late childhood, elevated phenylalanine can cause alterations in neurological functioning, leading to ADHD, speech delay and mild IQ reduction. In adolescents and adults, executive function and mood are affected, with some of the abnormalities reversed by better control of phenylalanine levels. Altered brain myelination can be present at this stage. In this article, we review the current knowledge about the consequences of high phenylalanine levels in PKU patients and animal models through different stages of brain development and its effect on cognitive, behavioural and neuropsychological function.
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Affiliation(s)
- Valentina Rovelli
- Clinical Department of Pediatrics, University of Milan, ASST Santi Paolo e Carlo, San Paolo Hospital, Milan, Italy.
| | - Nicola Longo
- Division of Medical Genetics, Department of Pediatrics, University of Utah, Salt Lake City, UT, USA
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4
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Nielsen MR, Jørgensen C, Ahring K, Lund AM, Ørngreen MC. The impact of phenylalanine levels during pregnancy on birth weight and later development in children born to women with phenylketonuria. J Inherit Metab Dis 2023. [PMID: 36843352 DOI: 10.1002/jimd.12600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 01/20/2023] [Accepted: 02/17/2023] [Indexed: 02/28/2023]
Abstract
Strict metabolic control with dietary treatment during pregnancy is essential for women with phenylketonuria (PKU), as elevated levels of phenylalanine (Phe) are toxic to the developing fetus. Maternal delay in achievement of the recommended Phe level during pregnancy is associated with delayed development of the child. However, the extent to which risk is changed by later or less stringently performed dietary treatment is unclear. The aim of this study was to investigate the impact of Phe levels and time of initiation of a Phe-restricted diet in pregnant women with PKU on birth weight, head circumference and later development of their children. Birth data were obtained from the medical records of women with PKU giving birth in the period 1980-2020. Later development was investigated by interviewing the mothers about their children's development and health. We included 79 children of 41 women with PKU. The women showed good adherence with the diet and had mean blood Phe levels within target range (248 ± 62 μmol/L). The children's development was not affected by fluctuations in the women's Phe levels, that occurred especially in first trimester. Despite maternal Phe levels being within target range, 19 children (26.8%) had low birth weight below 10th percentile. This study indicates that with dietary treatment, the children are born with the same prospect for normal development and health as children born to non-PKU mothers. This is despite maternal fluctuations in the Phe levels during first trimester.
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Affiliation(s)
- Maja Risager Nielsen
- Centre for Inherited Metabolic Diseases, Department of Clinical Genetics and of Pediatrics and Adolescent Medicine, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Christine Jørgensen
- Centre for Inherited Metabolic Diseases, Department of Clinical Genetics and of Pediatrics and Adolescent Medicine, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Kirsten Ahring
- Centre for Inherited Metabolic Diseases, Department of Clinical Genetics and of Pediatrics and Adolescent Medicine, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Allan Meldgaard Lund
- Centre for Inherited Metabolic Diseases, Department of Clinical Genetics and of Pediatrics and Adolescent Medicine, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Mette Cathrine Ørngreen
- Centre for Inherited Metabolic Diseases, Department of Clinical Genetics and of Pediatrics and Adolescent Medicine, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
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5
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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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6
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Borges AC, Broersen K, Leandro P, Fernandes TG. Engineering Organoids for in vitro Modeling of Phenylketonuria. Front Mol Neurosci 2022; 14:787242. [PMID: 35082602 PMCID: PMC8784555 DOI: 10.3389/fnmol.2021.787242] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/29/2021] [Indexed: 12/15/2022] Open
Abstract
Phenylketonuria is a recessive genetic disorder of amino-acid metabolism, where impaired phenylalanine hydroxylase function leads to the accumulation of neurotoxic phenylalanine levels in the brain. Severe cognitive and neuronal impairment are observed in untreated/late-diagnosed patients, and even early treated ones are not safe from life-long sequelae. Despite the wealth of knowledge acquired from available disease models, the chronic effect of Phenylketonuria in the brain is still poorly understood and the consequences to the aging brain remain an open question. Thus, there is the need for better predictive models, able to recapitulate specific mechanisms of this disease. Human induced pluripotent stem cells (hiPSCs), with their ability to differentiate and self-organize in multiple tissues, might provide a new exciting in vitro platform to model specific PKU-derived neuronal impairment. In this review, we gather what is known about the impact of phenylalanine in the brain of patients and highlight where hiPSC-derived organoids could contribute to the understanding of this disease.
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Affiliation(s)
- Alice C. Borges
- Department of Bioengineering and iBB – Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
- Associate Laboratory i4HB – Institute for Health and Bioeconomy, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Kerensa Broersen
- Department of Applied Stem Cell Technologies, Faculty of Science and Technology, Technical Medical Centre, University of Twente, Enschede, Netherlands
| | - Paula Leandro
- Faculty of Pharmacy, iMed.ULisboa - Research Institute for Medicines, Universidade de Lisboa, Lisbon, Portugal
| | - Tiago G. Fernandes
- Department of Bioengineering and iBB – Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
- Associate Laboratory i4HB – Institute for Health and Bioeconomy, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
- *Correspondence: Tiago G. Fernandes,
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7
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Vernon HJ, Manoli I. Milestones in treatments for inborn errors of metabolism: Reflections on Where chemistry and medicine meet. Am J Med Genet A 2021; 185:3350-3358. [PMID: 34165242 DOI: 10.1002/ajmg.a.62385] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 05/23/2021] [Accepted: 05/25/2021] [Indexed: 12/16/2022]
Abstract
From Sir Archibald Garrod's initial description of the tetrad of albinism, alkaptonuria, cystinuria, and pentosuria to today, the field of medicine dedicated to inborn errors of metabolism has evolved from disease identification and mechanistic discovery to the development of therapies designed to subvert biochemical defects. In this review, we highlight major milestones in the treatment and diagnosis of inborn errors of metabolism, starting with dietary therapy for phenylketonuria in the 1950s and 1960s, and ending with current approaches in genetic manipulation.
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Affiliation(s)
- Hilary J Vernon
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Irini Manoli
- Medical Genomics and Metabolic Genetics Branch, National Human Genome Research Institute, National Institutes of Health (NIH), Bethesda, Maryland, USA
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8
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Koppes EA, Redel BK, Johnson MA, Skvorak KJ, Ghaloul-Gonzalez L, Yates ME, Lewis DW, Gollin SM, Wu YL, Christ SE, Yerle M, Leshinski A, Spate LD, Benne JA, Murphy SL, Samuel MS, Walters EM, Hansen SA, Wells KD, Lichter-Konecki U, Wagner RA, Newsome JT, Dobrowolski SF, Vockley J, Prather RS, Nicholls RD. A porcine model of phenylketonuria generated by CRISPR/Cas9 genome editing. JCI Insight 2020; 5:141523. [PMID: 33055427 PMCID: PMC7605535 DOI: 10.1172/jci.insight.141523] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 09/17/2020] [Indexed: 12/17/2022] Open
Abstract
Phenylalanine hydroxylase-deficient (PAH-deficient) phenylketonuria (PKU) results in systemic hyperphenylalaninemia, leading to neurotoxicity with severe developmental disabilities. Dietary phenylalanine (Phe) restriction prevents the most deleterious effects of hyperphenylalaninemia, but adherence to diet is poor in adult and adolescent patients, resulting in characteristic neurobehavioral phenotypes. Thus, an urgent need exists for new treatments. Additionally, rodent models of PKU do not adequately reflect neurocognitive phenotypes, and thus there is a need for improved animal models. To this end, we have developed PAH-null pigs. After selection of optimal CRISPR/Cas9 genome-editing reagents by using an in vitro cell model, zygote injection of 2 sgRNAs and Cas9 mRNA demonstrated deletions in preimplantation embryos, with embryo transfer to a surrogate leading to 2 founder animals. One pig was heterozygous for a PAH exon 6 deletion allele, while the other was compound heterozygous for deletions of exon 6 and of exons 6-7. The affected pig exhibited hyperphenylalaninemia (2000-5000 μM) that was treatable by dietary Phe restriction, consistent with classical PKU, along with juvenile growth retardation, hypopigmentation, ventriculomegaly, and decreased brain gray matter volume. In conclusion, we have established a large-animal preclinical model of PKU to investigate pathophysiology and to assess new therapeutic interventions.
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Affiliation(s)
- Erik A Koppes
- Division of Medical Genetics, Department of Pediatrics, University of Pittsburgh School of Medicine, and Universityof Pittsburgh Medical Center (UPMC) Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Bethany K Redel
- Division ofAnimal Sciences, College of Agriculture, Food and Natural Resources, University of Missouri, Columbia, Missouri, USA.,National Swine Research and Resource Center (NSRRC), College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA
| | - Marie A Johnson
- Division of Medical Genetics, Department of Pediatrics, University of Pittsburgh School of Medicine, and Universityof Pittsburgh Medical Center (UPMC) Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Kristen J Skvorak
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Lina Ghaloul-Gonzalez
- Division of Medical Genetics, Department of Pediatrics, University of Pittsburgh School of Medicine, and Universityof Pittsburgh Medical Center (UPMC) Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Human Genetics, University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania, USA
| | - Megan E Yates
- Division of Medical Genetics, Department of Pediatrics, University of Pittsburgh School of Medicine, and Universityof Pittsburgh Medical Center (UPMC) Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Dale W Lewis
- Department of Human Genetics, University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania, USA
| | - Susanne M Gollin
- Department of Human Genetics, University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania, USA
| | - Yijen L Wu
- Department of Developmental Biology, University of Pittsburgh, and UPMC Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Shawn E Christ
- Department of Psychological Sciences, University of Missouri, Columbia, Missouri, USA
| | - Martine Yerle
- GenPhySE, Université de Toulouse, INRAE, ENVT, 31326, Castanet-Tolosan, France
| | - Angela Leshinski
- Division of Medical Genetics, Department of Pediatrics, University of Pittsburgh School of Medicine, and Universityof Pittsburgh Medical Center (UPMC) Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Lee D Spate
- Division ofAnimal Sciences, College of Agriculture, Food and Natural Resources, University of Missouri, Columbia, Missouri, USA.,National Swine Research and Resource Center (NSRRC), College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA
| | - Joshua A Benne
- National Swine Research and Resource Center (NSRRC), College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA
| | - Stephanie L Murphy
- National Swine Research and Resource Center (NSRRC), College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA
| | - Melissa S Samuel
- Division ofAnimal Sciences, College of Agriculture, Food and Natural Resources, University of Missouri, Columbia, Missouri, USA.,National Swine Research and Resource Center (NSRRC), College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA
| | - Eric M Walters
- Division ofAnimal Sciences, College of Agriculture, Food and Natural Resources, University of Missouri, Columbia, Missouri, USA.,National Swine Research and Resource Center (NSRRC), College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA
| | - Sarah A Hansen
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA
| | - Kevin D Wells
- Division ofAnimal Sciences, College of Agriculture, Food and Natural Resources, University of Missouri, Columbia, Missouri, USA.,National Swine Research and Resource Center (NSRRC), College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA
| | - Uta Lichter-Konecki
- Division of Medical Genetics, Department of Pediatrics, University of Pittsburgh School of Medicine, and Universityof Pittsburgh Medical Center (UPMC) Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Robert A Wagner
- Division of Laboratory Animal Resources, Office of Research, Health Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Joseph T Newsome
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.,Division of Laboratory Animal Resources, Office of Research, Health Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Steven F Dobrowolski
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Jerry Vockley
- Division of Medical Genetics, Department of Pediatrics, University of Pittsburgh School of Medicine, and Universityof Pittsburgh Medical Center (UPMC) Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Human Genetics, University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania, USA
| | - Randall S Prather
- Division ofAnimal Sciences, College of Agriculture, Food and Natural Resources, University of Missouri, Columbia, Missouri, USA.,National Swine Research and Resource Center (NSRRC), College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA
| | - Robert D Nicholls
- Division of Medical Genetics, Department of Pediatrics, University of Pittsburgh School of Medicine, and Universityof Pittsburgh Medical Center (UPMC) Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA
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9
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Kalisch-Smith JI, Ved N, Sparrow DB. Environmental Risk Factors for Congenital Heart Disease. Cold Spring Harb Perspect Biol 2020; 12:a037234. [PMID: 31548181 PMCID: PMC7050589 DOI: 10.1101/cshperspect.a037234] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Congenital heart disease (CHD) has many forms and a wide range of causes. Clinically, it is important to understand the causes. This allows estimation of recurrence rate, guides treatment options, and may also be used to formulate public health advice to reduce the population prevalence of CHD. The recent advent of sophisticated genetic and genomic methods has led to the identification of more than 100 genes associated with CHD. However, despite these great strides, to date only one-third of CHD cases have been shown to have a simple genetic cause. This is because CHD can also be caused by oligogenic factors, environmental factors, and/or gene-environment interaction. Although solid evidence for environmental causes of CHD have been available for almost 80 years, it is only very recently that the molecular mechanisms for these risk factors have begun to be investigated. In this review, we describe the most important environmental CHD risk factors, and what is known about how they cause CHD.
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Affiliation(s)
| | - Nikita Ved
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, Oxfordshire OX1 3PT, United Kingdom
| | - Duncan Burnaby Sparrow
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, Oxfordshire OX1 3PT, United Kingdom
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10
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Phenylalanine and tyrosine measurements across gestation by tandem mass spectrometer on dried blood spot cards from normal pregnant women. Genet Med 2019; 21:1821-1826. [PMID: 30626901 PMCID: PMC6620164 DOI: 10.1038/s41436-018-0407-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 12/05/2018] [Indexed: 12/22/2022] Open
Abstract
Purpose: Maternal phenylketonuria (MPKU) requires strict control of phenylalanine (Phe) and supplemental tyrosine (Tyr). Monitoring during pregnancy using dried blood spot (DBS) cards by tandem mass spectrometry (MS/MS) is now standard practice, however there are no Phe and Tyr reference ranges for DBS MS/MS method in healthy pregnant women. Methods: DBS cards (63 −1364 days in storage) from healthy women with singleton pregnancies were analyzed by MS/MS. 390 DBS cards from 170 pregnancies (5/1–39/6 weeks’ gestation), were tested. Results: Both Phe and Tyr levels declined from the first trimester (Phe: 36.2 +/− 10.6; Tyr 25.7 +/−9.7 micromol/L) to the second trimester (Phe 33.4 +/− 9.3; Tyr 21.7 +/− 6.7 micromol/L) and remained stable in the third trimester (Phe 32.3 +/− 8.7; Tyr 21.0 +/− 6.6 micromol/L). Phe and Tyr levels declined over time since collection (Phe: 0.004 micromol/L per day; Tyr 0.002 micromol/L). Nomograms by gestational age were created using raw data and data adjusted for time from sample collection. Reference ranges by trimester are provided. Conclusion: Both Phe and Tyr decline quickly during the first trimester and remain relatively constant over the second and third trimesters. These nomograms will provide a valuable resource for care of MPKU.
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11
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Watson JN, Seagraves NJ. RNA-Seq analysis in an avian model of maternal phenylketonuria. Mol Genet Metab 2019; 126:23-29. [PMID: 30600150 DOI: 10.1016/j.ymgme.2018.09.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 09/03/2018] [Accepted: 09/03/2018] [Indexed: 01/28/2023]
Abstract
Cardiac malformations (CVMs) are a leading cause of infant morbidity and mortality. CVMs are particularly prevalent when the developing fetus is exposed to high levels of phenylalanine in-utero in mothers with Phenylketonuria. Yet, elucidating the underlying molecular mechanism leading to CVMs has proven difficult. In this study we used RNA-Seq to investigate an avian model of MPKU and establish differential gene expression (DEG) characteristics of the early developmental stages HH10, 12, and 14. In total, we identified 633 significantly differentially expressed genes across stages HH10, 12, and 14. As expected, functional annotation of significant DEGs identified associations seen in clinical phenotypes of MPKU including CVMs, congenital heart defects, craniofacial anomalies, central nervous system defects, and growth anomalies. Additionally, there was an overrepresentation of genes involved in cardiac muscle contraction, adrenergic signaling in cardiomyocytes, migration, proliferation, metabolism, and cell survival. Strikingly, we identified significant changes in expression with multiple genes involved in Retinoic Acid (RA) metabolism and downstream targets. Using qRTPCR, we validated these findings and identified a total of 42 genes within the RA pathway that are differentially expressed. Here, we report the first elucidation of the molecular mechanisms of cardiovascular malformations in MPKU conducted at early developmental timepoints. We provide evidence suggesting a link between PHE exposure and the alteration of RA pathway. These results are promising and offer novel findings associated with congenital heart defects in MPKU.
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Affiliation(s)
- Jamie N Watson
- Department of Biology, University of Central Oklahoma, Edmond, OK, USA.
| | - Nikki J Seagraves
- Department of Biology, University of Central Oklahoma, Edmond, OK, USA.
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12
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Belanger AM, Przybylska M, Gefteas E, Furgerson M, Geller S, Kloss A, Cheng SH, Zhu Y, Yew NS. Inhibiting neutral amino acid transport for the treatment of phenylketonuria. JCI Insight 2018; 3:121762. [PMID: 30046012 DOI: 10.1172/jci.insight.121762] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 06/19/2018] [Indexed: 12/21/2022] Open
Abstract
The neuropathological effects of phenylketonuria (PKU) stem from the inability of the body to metabolize excess phenylalanine (Phe), resulting in accumulation of Phe in the blood and brain. Since the kidney normally reabsorbs circulating amino acids with high efficiency, we hypothesized that preventing the renal uptake of Phe might provide a disposal pathway that could lower systemic Phe levels. SLC6A19 is a neutral amino acid transporter responsible for absorption of the majority of free Phe in the small intestine and reuptake of Phe by renal proximal tubule cells. Transgenic KO mice lacking SLC6A19 have elevated levels of Phe and other amino acids in their urine but are otherwise healthy. Here, we crossed the Pahenu2 mouse model of PKU with the Slc6a19-KO mouse. These mutant/KO mice exhibited abundant excretion of Phe in the urine and an approximately 70% decrease in plasma Phe levels. Importantly, brain Phe levels were decreased by 50%, and the levels of key neurotransmitters were increased in the mutant/KO mice. In addition, a deficit in spatial working memory and markers of neuropathology were corrected. Finally, treatment of Pahenu2 mice with Slc6a19 antisense oligonucleotides lowered Phe levels. The results suggest that inhibition of SLC6A19 may represent a novel approach for the treatment of PKU and related aminoacidopathies.
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MESH Headings
- Amines
- Amino Acid Transport Systems, Neutral/analysis
- Amino Acid Transport Systems, Neutral/genetics
- Amino Acid Transport Systems, Neutral/metabolism
- Amino Acids, Neutral/blood
- Amino Acids, Neutral/metabolism
- Animals
- Astrocytes/metabolism
- Astrocytes/pathology
- Biological Transport/drug effects
- Brain/metabolism
- Disease Models, Animal
- Female
- Gene Expression Regulation
- Genetic Diseases, Inborn/therapy
- Kidney Tubules, Proximal/drug effects
- Kidney Tubules, Proximal/metabolism
- Male
- Memory, Short-Term
- Mice
- Mice, Knockout
- Morpholinos/pharmacology
- Oligonucleotides/pharmacology
- Phenylalanine/blood
- Phenylalanine/metabolism
- Phenylketonurias/pathology
- Phenylketonurias/therapy
- Renal Reabsorption/drug effects
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13
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van Wegberg AMJ, MacDonald A, Ahring K, Bélanger-Quintana A, Blau N, Bosch AM, Burlina A, Campistol J, Feillet F, Giżewska M, Huijbregts SC, Kearney S, Leuzzi V, Maillot F, Muntau AC, van Rijn M, Trefz F, Walter JH, van Spronsen FJ. The complete European guidelines on phenylketonuria: diagnosis and treatment. Orphanet J Rare Dis 2017; 12:162. [PMID: 29025426 PMCID: PMC5639803 DOI: 10.1186/s13023-017-0685-2] [Citation(s) in RCA: 381] [Impact Index Per Article: 54.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 07/11/2017] [Indexed: 12/22/2022] Open
Abstract
Phenylketonuria (PKU) is an autosomal recessive inborn error of phenylalanine metabolism caused by deficiency in the enzyme phenylalanine hydroxylase that converts phenylalanine into tyrosine. If left untreated, PKU results in increased phenylalanine concentrations in blood and brain, which cause severe intellectual disability, epilepsy and behavioural problems. PKU management differs widely across Europe and therefore these guidelines have been developed aiming to optimize and standardize PKU care. Professionals from 10 different European countries developed the guidelines according to the AGREE (Appraisal of Guidelines for Research and Evaluation) method. Literature search, critical appraisal and evidence grading were conducted according to the SIGN (Scottish Intercollegiate Guidelines Network) method. The Delphi-method was used when there was no or little evidence available. External consultants reviewed the guidelines. Using these methods 70 statements were formulated based on the highest quality evidence available. The level of evidence of most recommendations is C or D. Although study designs and patient numbers are sub-optimal, many statements are convincing, important and relevant. In addition, knowledge gaps are identified which require further research in order to direct better care for the future.
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Affiliation(s)
- A. M. J. van Wegberg
- Division of Metabolic Diseases, Beatrix Children’s Hospital, University Medical Center Groningen, PO BOX 30.001, 9700 RB Groningen, The Netherlands
| | - A. MacDonald
- Dietetic Department, Birmingham Children’s Hospital, Birmingham, UK
| | - K. Ahring
- Department of PKU, Kennedy Centre, Glostrup, Denmark
| | - A. Bélanger-Quintana
- Metabolic Diseases Unit, Department of Paediatrics, Hospital Ramon y Cajal Madrid, Madrid, Spain
| | - N. Blau
- University Children’s Hospital, Dietmar-Hoppe Metabolic Centre, Heidelberg, Germany
- University Children’s Hospital Zürich, Zürich, Switzerland
| | - A. M. Bosch
- Department of Paediatrics, Division of Metabolic Disorders, Academic Medical Centre, University Hospital of Amsterdam, Amsterdam, The Netherlands
| | - A. Burlina
- Division of Inherited Metabolic Diseases, Department of Paediatrics, University Hospital of Padova, Padova, Italy
| | - J. Campistol
- Neuropaediatrics Department, Hospital Sant Joan de Déu, Universitat de Barcelona, Barcelona, Spain
| | - F. Feillet
- Department of Paediatrics, Hôpital d’Enfants Brabois, CHU Nancy, Vandoeuvre les Nancy, France
| | - M. Giżewska
- Department of Paediatrics, Endocrinology, Diabetology, Metabolic Diseases and Cardiology of the Developmental Age, Pomeranian Medical University, Szczecin, Poland
| | - S. C. Huijbregts
- Department of Clinical Child and Adolescent Studies-Neurodevelopmental Disorders, Faculty of Social Sciences, Leiden University, Leiden, The Netherlands
| | - S. Kearney
- Clinical Psychology Department, Birmingham Children’s Hospital, Birmingham, UK
| | - V. Leuzzi
- Department of Paediatrics, Child Neurology and Psychiatry, Sapienza University of Rome, Via dei Sabelli 108, 00185 Rome, Italy
| | - F. Maillot
- CHRU de Tours, Université François Rabelais, INSERM U1069, Tours, France
| | - A. C. Muntau
- University Children’s Hospital, University Medical Centre Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - M. van Rijn
- Division of Metabolic Diseases, Beatrix Children’s Hospital, University Medical Center Groningen, PO BOX 30.001, 9700 RB Groningen, The Netherlands
| | - F. Trefz
- Department of Paediatrics, University of Heidelberg, Heidelberg, Germany
| | - J. H. Walter
- Medicine, Manchester Academic Health Sciences Centre, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
| | - F. J. van Spronsen
- Division of Metabolic Diseases, Beatrix Children’s Hospital, University Medical Center Groningen, PO BOX 30.001, 9700 RB Groningen, The Netherlands
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14
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Matalon R, Surendran S, McDonald JD, Okorodudu AO, Tyring SK, Michals-Matalon K, Harris P. Abnormal Expression of Genes Associated with Development and Inflammation in the Heart of Mouse Maternal Phenylketonuria Offspring. Int J Immunopathol Pharmacol 2016; 18:557-65. [PMID: 16164837 DOI: 10.1177/039463200501800316] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
This study descibes gene expression in the fetus hearts obtained from mouse model for Phenylketonuria. These hearts have cardiovascular disease (CVD). Therefore genes involved in CVD were examined. Several genes associated with heart development and inflammation were found to be altered. In order to investigate whether the abnormal gene expression alters transcription and translation, the levels of troponin mRNA and protein were determined. One step real time RT-PCR showed a reduction in cardiac troponin I, troponin T2 and ryanodine receptor 2. Determination of troponin I and T protein levels showed reduced levels of these proteins. Our results suggest that altered gene expression affects protein production. These changes are likely involved in the cardiovascular defects seen in the mouse.
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Affiliation(s)
- R Matalon
- Department of Pediatrics, The University of Texas Medical Branch (UTMB), Galveston, Texas 77555-0632, USA
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15
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Abstract
BACKGROUND Phenylketonuria is an inherited metabolic disorder characterised by an absence or deficiency of the enzyme phenylalanine hydroxylase. The aim of treatment is to lower blood phenylalanine concentrations to the recommended therapeutic range to prevent developmental delay and support normal growth. Current treatment consists of a low-phenylalanine diet in combination with a protein substitute which is free from or low in phenylalanine. Guidance regarding the use, dosage, and distribution of dosage of the protein substitute over a 24-hour period is unclear, and there is variation in recommendations among treatment centres. This is an update of a Cochrane review first published in 2005, and previously updated in 2008. OBJECTIVES To assess the benefits and adverse effects of protein substitute, its dosage, and distribution of dose in children and adults with phenylketonuria who are adhering to a low-phenylalanine diet. SEARCH METHODS We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register which consists of references identified from comprehensive electronic database searches and hand searches of relevant journals and abstract books of conference proceedings. We also contacted manufacturers of the phenylalanine-free and low-phenylalanine protein substitutes for any data from published and unpublished randomised controlled trials.Date of the most recent search of the Group's Inborn Errors of Metabolism Trials Register: 03 April 2014. SELECTION CRITERIA All randomised or quasi-randomised controlled trials comparing: any dose of protein substitute with no protein substitute; an alternative dosage; or the same dose, but given as frequent small doses throughout the day compared with the same total daily dose given as larger boluses less frequently. DATA COLLECTION AND ANALYSIS Both authors independently extracted data and assessed trial quality. MAIN RESULTS Three trials (69 participants) are included in this review. One trial investigated the use of protein substitute in 16 participants, while a further two trials investigated the dosage of protein substitute in a total of 53 participants. Due to issues with data presentation in each trial, described in full in the review, formal statistical analyses of the data were impossible. Investigators will be contacted for further information. AUTHORS' CONCLUSIONS No conclusions could be drawn about the short- or long-term use of protein substitute in phenylketonuria due to the lack of adequate or analysable trial data. Additional data and randomised controlled trials are needed to investigate the use of protein substitute in phenylketonuria. Until further evidence is available, current practice in the use of protein substitute should continue to be monitored with care.
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Affiliation(s)
- Sarah HL Yi
- Emory Genetics Metabolic Nutrition Program2165 N. Decatur RoadDecaturGeorgiaUSA30033
| | - Rani H Singh
- Emory University School of MedicineDepartment of Human Genetics2165 North Decatur RoadDecaturGeorgiaUSA30033
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16
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Hozyasz KK, Mostowska A, Wójcicki P, Lasota A, Wołkowicz A, Dunin-Wilczyńska I, Jagodziński PP. Association of common variants in PAH and LAT1 with non-syndromic cleft lip with or without cleft palate (NSCL/P) in the Polish population. Arch Oral Biol 2014; 59:363-9. [PMID: 24606907 DOI: 10.1016/j.archoralbio.2014.01.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 12/23/2013] [Accepted: 01/06/2014] [Indexed: 11/30/2022]
Abstract
BACKGROUND Non-syndromic cleft lip with or without cleft palate (NSCL/P) is a common structural malformation with a complex and multifactorial aetiology. Associations of abnormalities in phenylalanine metabolism and orofacial clefts have been suggested. METHODS Eight single nucleotide polymorphisms (SNPs) of genes encoding phenylalanine hydroxylase (PAH) and large neutral l-amino acid transporter type 1 (LAT1), as well as the PAH mutation that is most common in the Polish population (rs5030858; R408W), were investigated in 263 patients with NSCL/P and 270 matched controls using high resolution melting curve analysis (HRM). RESULTS We found that two polymorphic variants of PAH appear to be risk factors for NSCL/P. The odds ratio (OR) for individuals with the rs7485331 A allele (AC or AA) compared to CC homozygotes was 0.616 (95% confidence interval [CI]=0.437-0.868; p=0.005) and this association remains statistically significant after multiple testing correction. The PAH rs12425434, previously associated with schizophrenia, was borderline associated with orofacial clefts. Moreover, haplotype analysis of polymorphisms in the PAH gene revealed a 4-marker combination that was significantly associated with NSCL/P. The global p-value for a haplotype comprised of SNPs rs74385331, rs12425434, rs1722392, and the mutation rs5030858 was 0.032, but this association did not survive multiple testing correction. CONCLUSION This study suggests the involvement of the PAH gene in the aetiology of NSCL/P in the tested population. Further replication will be required in separate cohorts to confirm the consistency of the observed association.
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Affiliation(s)
- Kamil K Hozyasz
- Department of Paediatrics, Institute of Mother and Child, Warsaw, Poland.
| | - Adrianna Mostowska
- Department of Biochemistry and Molecular Biology, Poznan University of Medical Sciences, Poznan, Poland
| | - Piotr Wójcicki
- University Clinic of Medical Academy, Wroclaw, Poland; Department of Plastic Surgery, Specialist Medical Center, Polanica Zdroj, Poland
| | - Agnieszka Lasota
- Department of Jaw Orthopaedics, Medical University of Lublin, Lublin, Poland
| | - Anna Wołkowicz
- Department of Paediatrics, Institute of Mother and Child, Warsaw, Poland
| | | | - Paweł P Jagodziński
- Department of Biochemistry and Molecular Biology, Poznan University of Medical Sciences, Poznan, Poland
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17
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Soloway AH, Soloway PD, Warner VD. Possible chemical initiators of cognitive dysfunction in phenylketonuria, Parkinson’s disease and Alzheimer’s disease. Med Hypotheses 2013; 81:690-4. [DOI: 10.1016/j.mehy.2013.07.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 07/07/2013] [Accepted: 07/13/2013] [Indexed: 01/20/2023]
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18
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Martino T, Koerner C, Yenokyan G, Hoover-Fong J, Hamosh A. Maternal hyperphenylalaninemia: rapid achievement of metabolic control predicts overall control throughout pregnancy. Mol Genet Metab 2013; 109:3-8. [PMID: 23537842 PMCID: PMC3639475 DOI: 10.1016/j.ymgme.2013.02.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 02/12/2013] [Accepted: 02/12/2013] [Indexed: 10/27/2022]
Abstract
Women with hyperphenylalaninemia are at risk of having offspring affected with the maternal phenylketonuria syndrome. Here we analyze the effect of the intervention of a nutritionist on plasma phenylalanine control in Maternal Hyperphenylalaninemia. We analyzed a retrospective cohort of 35 completed pregnancies in 20 women with Maternal Hyperphenylalaninemia who visited the metabolic nutritionist during the pregnancy to achieve metabolic control. Women who promptly achieved metabolic control had lower plasma phenylalanine concentrations for the remainder of the pregnancy when compared to women who did not achieve prompt control, and this difference reached statistical significance. The achievement of plasma phenylalanine concentrations within the desired target range by the time of the second visit to the nutritionist is a strong predictor of the ability to maintain the desired target range of plasma phenylalanine for the remainder of the pregnancy. Furthermore, we demonstrate that phenylalanine tolerance increases significantly by trimester in women with classical and variant hyperphenylalaninemia.
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Affiliation(s)
- Teresa Martino
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Blalock 1008, Baltimore, MD 21287, USA, Phone: 1.443.287.4588, Fax: 1.410.614.9246
| | - Celide Koerner
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Blalock 1008, Baltimore, MD 21287, USA, Phone: 1.443.287.4588, Fax: 1.410.614.9246
| | - Gayane Yenokyan
- Johns Hopkins Biostatistics Center, Bloomberg School of Public Health, 615 North Wolfe Street, Room E3153, Baltimore, MD, 21205, USA
| | - Julie Hoover-Fong
- McKusick-Nathans Institute of Genetic Medicine, Greenberg Center for Skeletal Dysplasias, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, MD 21287, USA
| | - Ada Hamosh
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Blalock 1008, Baltimore, MD 21287, USA, Phone: 1.443.287.4588, Fax: 1.410.614.9246
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19
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Schwoerer JAS, Obernolte L, Van Calcar S, Heighway S, Bankowski H, Williams P, Rice G. Use of Gastrostomy Tube to Prevent Maternal PKU Syndrome. JIMD Rep 2013; 6:15-20. [PMID: 23430933 DOI: 10.1007/8904_2011_95] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Revised: 09/13/2011] [Accepted: 09/19/2011] [Indexed: 02/16/2023] Open
Abstract
Maternal Phenylketonuria Syndrome (MPKU) can occur in infants born to mothers with PKU with poor metabolic control during pregnancy. Elevated phenylalanine (phe) acts as a teratogen to the developing fetus with consequences including intellectual disability, microcephaly, facial dysmorphism, growth retardation, and congenital heart disease. MPKU can be prevented if metabolic control is achieved by 8-10 weeks gestation. If control is not achieved, there is a significant risk for MPKU. Therefore, in women with poor metabolic control at time of pregnancy, establishing metabolic control quickly is important.Clinically, establishing metabolic control in women with PKU can present challenges. Social issues, psychological issues, and insufficient education about PKU play an important role in a patient's inability to reinstitute this challenging diet. Maintaining phe levels within a range to allow for infant growth, while preventing toxicity, is challenging, particularly for those women who no longer follow the PKU diet. Gastrostomy tube placement is an option to deliver medical formula to women who are unable to restart diet due to severe nausea or palatability issues.Here we discuss two pregnancies in which a gastrostomy tube was placed to achieve metabolic control after other measures failed to reduce phe concentrations into the recommended range. For these two pregnancies, placement of the gastrostomy tube led to improvement in phe levels with normal infant outcomes including normal growth, head circumference, and heart structure.
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20
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Stéphenne X, Debray FG, Smets F, Jazouli N, Sana G, Tondreau T, Menten R, Goffette P, Boemer F, Schoos R, Gersting SW, Najimi M, Muntau AC, Goyens P, Sokal EM. Hepatocyte Transplantation Using the Domino Concept in a Child with Tetrabiopterin Nonresponsive Phenylketonuria. Cell Transplant 2012; 21:2765-70. [DOI: 10.3727/096368912x653255] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Phenylketonuria is a metabolic disease caused by phenylalanine hydroxylase deficiency. Treatment is based on a strict natural protein-restricted diet that is associated with the risk of malnutrition and severe psychosocial burden. Oral administration of tetrahydrobiopterin can increase residual enzyme activity, but most patients with severe clinical phenotypes are nonresponders. We performed liver cell transplantation in a 6-year-old boy with severe tetrahydrobiopterin nonresponsive phenylketonuria who failed to comply with diet prescriptions. The transplanted hepatocytes were obtained in part from an explanted glycogen storage type 1b liver. Following two infusions, blood phenylalanine levels returned within the therapeutic target while the phenylalanine half-life assessed by loading tests decreased from 43 to 19 h. However, 3 months later, blood phenylalanine concentrations increased and the phenylalanine intake had to be reduced. Cell-based therapy is a promising therapeutic option in phenylketonuria, and the domino concept may solve the issue of cell sources for hepatocyte transplantation.
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Affiliation(s)
- X. Stéphenne
- Université Catholique de Louvain, Cliniques Universitaires St Luc, Service de Gastroentérologie et Hépatologie Pédiatrique, Banque D'hépatocytes, Bruxelles, Belgium
- Université Catholique de Louvain, Institut de Recherche Expérimentale et Clinique (IREC), Laboratoire D'hépatologie Pédiatrique & Thérapie Cellulaire, Brussels, Belgium
| | - F. G. Debray
- CHU & Université de Liège, Centre de Génétique Humaine, Liège, Belgium
| | - F. Smets
- Université Catholique de Louvain, Cliniques Universitaires St Luc, Service de Gastroentérologie et Hépatologie Pédiatrique, Banque D'hépatocytes, Bruxelles, Belgium
- Université Catholique de Louvain, Institut de Recherche Expérimentale et Clinique (IREC), Laboratoire D'hépatologie Pédiatrique & Thérapie Cellulaire, Brussels, Belgium
| | - N. Jazouli
- Université Catholique de Louvain, Cliniques Universitaires St Luc, Service de Gastroentérologie et Hépatologie Pédiatrique, Banque D'hépatocytes, Bruxelles, Belgium
- Université Catholique de Louvain, Institut de Recherche Expérimentale et Clinique (IREC), Laboratoire D'hépatologie Pédiatrique & Thérapie Cellulaire, Brussels, Belgium
| | - G. Sana
- Université Catholique de Louvain, Cliniques Universitaires St Luc, Service de Gastroentérologie et Hépatologie Pédiatrique, Banque D'hépatocytes, Bruxelles, Belgium
- Université Catholique de Louvain, Institut de Recherche Expérimentale et Clinique (IREC), Laboratoire D'hépatologie Pédiatrique & Thérapie Cellulaire, Brussels, Belgium
| | - T. Tondreau
- Université Catholique de Louvain, Cliniques Universitaires St Luc, Service de Gastroentérologie et Hépatologie Pédiatrique, Banque D'hépatocytes, Bruxelles, Belgium
- Université Catholique de Louvain, Institut de Recherche Expérimentale et Clinique (IREC), Laboratoire D'hépatologie Pédiatrique & Thérapie Cellulaire, Brussels, Belgium
| | - R. Menten
- Université Catholique de Louvain, Cliniques Universitaires St Luc, Unité de Radiologie Pédiatrique, Bruxelles, Belgium
| | - P. Goffette
- Université Catholique de Louvain, Cliniques Universitaires St Luc, Unité de Radiologie Pédiatrique, Bruxelles, Belgium
| | - F. Boemer
- CHU & Université de Liège, Genetic Biochemistry Laboratory, Liège, Belgium
| | - R. Schoos
- CHU & Université de Liège, Genetic Biochemistry Laboratory, Liège, Belgium
| | - S. W. Gersting
- Dr. von Hauner Children's Hospital, Division of Molecular Pediatrics, Munich, Germany
| | - M. Najimi
- Université Catholique de Louvain, Institut de Recherche Expérimentale et Clinique (IREC), Laboratoire D'hépatologie Pédiatrique & Thérapie Cellulaire, Brussels, Belgium
| | - A. C. Muntau
- Dr. von Hauner Children's Hospital, Division of Molecular Pediatrics, Munich, Germany
| | - P. Goyens
- Université Libre de Bruxelles, Unité de Nutrition et Métabolisme & Laboratoire de Pédiatrie, Bruxelles, Belgium
| | - E. M. Sokal
- Université Catholique de Louvain, Cliniques Universitaires St Luc, Service de Gastroentérologie et Hépatologie Pédiatrique, Banque D'hépatocytes, Bruxelles, Belgium
- Université Catholique de Louvain, Institut de Recherche Expérimentale et Clinique (IREC), Laboratoire D'hépatologie Pédiatrique & Thérapie Cellulaire, Brussels, Belgium
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21
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Ballhausen D, Egli D, Bickle-Graz M, Bianchi N, Bonafé L. Born at 27 weeks of gestation with classical PKU: challenges of dietetic management in a very preterm infant. Pediatr Rep 2011; 3:e26. [PMID: 22355511 PMCID: PMC3283194 DOI: 10.4081/pr.2011.e26] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Revised: 09/07/2011] [Accepted: 09/22/2011] [Indexed: 11/27/2022] Open
Abstract
Few cases of premature infants with classical phenylketonuria (PKU) have been reported. Treatment of these patients is challenging due to the lack of a phenylalanine (Phe)-free amino acid (AA) solution for parenteral nutrition. A boy born at 27 weeks of gestation with a weight of 1000 g was diagnosed with classical PKU on day 7 because of highly elevated Phe level at newborn screening (2800 µmol/L). Phe intake was suspended for 5 days and during this time intravenous glucose and lipids as well as small amounts of Phe-free formula through nasogastric tube were given. Because of insufficient weight gain attributable to deficiency of essential AA, a Phe-reduced, BCAA-enriched parenteral nutrition was added to satisfy AA requirements without overloading in Phe. Under this regimen, the boy started to gain weight, Phe plasma levels progressively reduced and normalized on day 19. At the age of 40 months, the patient shows normal growth parameters (height 25th percentile, weight 25-50(th) percentile, head circumference 50(th) percentile) with a normal result for formally tested psychomotor development (WPPSI-III). The good outcome of the patient in spite of over 2 weeks of extremely high Phe concentrations suggests that the premature brain may still have enough plasticity to recover. Lacking a Phe-free intravenous AA solution, successful management of premature infants with PKU depends on the child's tolerance of enteral nutrition. Although the coincidence of PKU and prematurity is rare, there is strong need for the development of an appropriate Phe-free amino acid solution for parenteral nutrition especially in case of gastro-intestinal complications of prematurity.
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Dawson C, Murphy E, Maritz C, Chan H, Ellerton C, Carpenter RHS, Lachmann RH. Dietary treatment of phenylketonuria: the effect of phenylalanine on reaction time. J Inherit Metab Dis 2011; 34:449-54. [PMID: 21290182 DOI: 10.1007/s10545-010-9276-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Revised: 11/30/2010] [Accepted: 12/28/2010] [Indexed: 11/24/2022]
Abstract
There is no evidence that high phenylalanine (Phe) levels have irreversible effects on the adult brain. Many adults with phenylketonuria (PKU) no longer follow a protein-restricted diet. Neuropsychological studies have shown that reaction time in adults with PKU is slower than controls. There are no data to show that this is directly related to Phe levels. Another way to assess reaction time is to measure saccadic latency. We have used a portable, head-mounted saccadometer to measure latency in the outpatient setting. Patients with PKU were split into three groups: off-diet (Phe >1,200 μmol/l), on-diet (Phe < 800 μmol/l) and maternal diet (Phe 100-400 μmol/l ). Reciprocal median latency (RML) was compared between groups. Latency was significantly slower in patients who were off-diet than in patients on-diet, on a maternal diet or in normal controls. Reaction times in both diet-treated groups were not significantly different from normal controls. In 16 women planning pregnancy we obtained values before and after they commenced the maternal diet. Stricter control of Phe levels resulted in a significant improvement in reaction times. We conclude that saccadometry is useful in monitoring PKU patients. Adult patients with PKU not on a protein-restricted diet have significantly slower reaction times than controls. In addition, off-diet patients have significantly slower reaction times than on-diet. Paired data show that effects of Phe levels on reaction time are reversible.
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Affiliation(s)
- Charlotte Dawson
- Charles Dent Metabolic Unit, National Hospital for Neurology and Neurosurgery, London, WC1N 3BG, UK
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23
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Illsinger S, Das AM. Impact of selected inborn errors of metabolism on prenatal and neonatal development. IUBMB Life 2010; 62:403-13. [PMID: 20503433 DOI: 10.1002/iub.336] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
In general, data regarding maturational processes of different metabolic pathways in the very vulnerable fetal and neonatal period are rare. This review is to substantiate the impact of selected inborn errors of metabolism on this critical period of life and their clinical manifestation. Significant adaptation of mitochondrial/energy-, carbohydrate-, lysosomal-, and amino acid-metabolism occurs during early prenatal and neonatal development. In utero, metabolic environment has an impact on the development of the fetus as well as fetal organ maturation. Defects of distinct metabolic pathways could therefore already be of significant relevance in utero and for clinical manifestations in the early fetal and neonatal period. Disturbances of these pathways may influence intrauterine growth and health. Production of a toxic intrauterine milieu, energy-deficiency, modification of membrane function, or disturbance of the normal intrauterine expression of genes may be responsible for fetal compromise and developmental disorders. Three categories of metabolic disorders will be discussed: the "intoxication type" (classical galactosemia, ornithine transcarbamylase deficiency, and "maternal phenylketonuria"), the "storage type" (Morbus Niemann Pick type C), and the "energy deficient type" (including long-chain fatty acid oxidation disorders, pyruvate dehydrogenase deficiency, and respiratory chain defects). For these disorders, the pathophysiology of early manifestation, special aspects regarding the prenatal and neonatal period, and diagnostic as well as therapeutic options are presented.
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Affiliation(s)
- Sabine Illsinger
- Clinic for Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Germany.
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Vernon HJ, Koerner C, Johnson M, Bergner A, Hamosh A. Introduction of sapropterin dihydrochloride as standard of care in patients with phenylketonuria. Mol Genet Metab 2010; 100:229-33. [PMID: 20418136 PMCID: PMC3135651 DOI: 10.1016/j.ymgme.2010.03.022] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2010] [Revised: 03/30/2010] [Accepted: 03/30/2010] [Indexed: 11/24/2022]
Abstract
Sapropterin dihydrochloride, a synthetic, stable form of the tetrahydrobiopterin cofactor of phenylalanine hydroxylase, has been shown to reduce plasma phenylalanine (Phe) levels in a significant portion of patients with phenylketonuria (PKU). When we undertook introducing this medication to our PKU clinic population, the challenges of recalling and reconnecting with a variably treated and variably compliant patient population became apparent. We offered a trial of sapropterin to all of our clinic patients with PKU. In order to determine responsiveness, we used a two tier dose escalation protocol. After diet records were taken, and baseline plasma Phe levels were established, a 7-day trial of sapropterin at 10mg/kg/day was started. At day 8, plasma phenylalanine levels were measured. Patients were considered to be responders if they had a 30% reduction in plasma Phe. If they did not respond, the dose of sapropterin was increased to 20 mg/kg/day, and levels were rechecked again in 8 days. Patients who were not responders at this time continued sapropterin for a total of 30 days and had Phe levels checked one last time. Patients who were responders and who were on a Phe-restricted diet underwent gradual liberalization of their diet to the maximum tolerated natural protein intake while still maintaining plasma levels in the acceptable treatment range of 120-360 micromol/L. In our population, 36/39 patients with hyperphenylalaninemia (HPA) who were offered a trial of sapropterin elected to start sapropterin. Five of 36 patients were non-adherent with diet records and/or medication doses and we were unable to determine if they were responders. We were unable to categorize 2 of 31 of the patients who completed the trial as responders due to dietary issues, though they were probably responders. Of the 29 patients who completed the sapropterin trial and we could categorize, 18/29 (62%) were determined to be responders. Patients were classified based on their off-diet diagnostic plasma phenylalanine levels as classical PKU (>1200 micromol/L) and variant PKU (>400 and <1200 micromol/L). The group with variant PKU had a 100% response rate, and patients with classical PKU had a 27% response rate. For the patients in the responder group who were on Phe-restricted diet, we were able to liberalize most diets, in two cases to unrestricted protein intake. We also had unexpected beneficial findings in our clinic experience, including positive behavioral improvements in an adult severely affected by untreated PKU. Even in patients who were not considered to be responders, the introduction of sapropterin provided a tool to reconnect with patients and re-introduce beneficial dietary measures.
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Affiliation(s)
- HJ Vernon
- McKusick Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Blalock 1006, 600 North Wolfe Street, Baltimore, MD 21287, United States of America
| | - C Koerner
- McKusick Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Blalock 1006, 600 North Wolfe Street, Baltimore, MD 21287, United States of America
| | - M Johnson
- McKusick Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Blalock 1006, 600 North Wolfe Street, Baltimore, MD 21287, United States of America
| | - A Bergner
- McKusick Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Blalock 1006, 600 North Wolfe Street, Baltimore, MD 21287, United States of America
| | - A Hamosh
- McKusick Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Blalock 1006, 600 North Wolfe Street, Baltimore, MD 21287, United States of America
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Rebuffat A, Harding CO, Ding Z, Thöny B. Comparison of adeno-associated virus pseudotype 1, 2, and 8 vectors administered by intramuscular injection in the treatment of murine phenylketonuria. Hum Gene Ther 2010; 21:463-77. [PMID: 19916803 PMCID: PMC2865356 DOI: 10.1089/hum.2009.127] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2009] [Accepted: 11/15/2009] [Indexed: 12/20/2022] Open
Abstract
Phenylketonuria (PKU) is caused by hepatic phenylalanine hydroxylase (PAH) deficiency and is associated with systemic accumulation of phenylalanine (Phe). Previously we demonstrated correction of murine PKU after intravenous injection of a recombinant type 2 adeno-associated viral vector pseudotyped with type 8 capsid (rAAV2/8), which successfully directed hepatic transduction and Pah gene expression. Here, we report that liver PAH activity and phenylalanine clearance were also restored in PAH-deficient mice after simple intramuscular injection of either AAV2 pseudotype 1 (rAAV2/1) or rAAV2/8 vectors. Serotype 2 AAV vector (rAAV2/2) was also investigated, but long-term phenylalanine clearance has been observed only for pseudotypes 1 and 8. Therapeutic correction was shown in both male and female mice, albeit more effectively in males, in which correction lasted for the entire period of the experiment (>1 year). Although phenylalanine levels began to rise in female mice at about 8-10 months after rAAV2/8 injection they remained only mildly hyperphenylalaninemic thereafter and subsequent supplementation with synthetic tetrahydrobiopterin resulted in a transient decrease in blood phenylalanine. Alternatively, subsequent administration of a second vector with a different AAV pseudotype to avoid immunity against the previously administrated vector was also successful for long-term treatment of female PKU mice. Overall, this relatively less invasive gene transfer approach completes our previous studies and allows comparison of complementary strategies in the development of efficient PKU gene therapy protocols.
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Affiliation(s)
- Alexandre Rebuffat
- Division of Clinical Chemistry and Biochemistry, Department of Pediatrics, University of Zürich, CH-8032 Zürich, Switzerland
| | - Cary O. Harding
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR 97201, USA
| | - Zhaobing Ding
- Division of Clinical Chemistry and Biochemistry, Department of Pediatrics, University of Zürich, CH-8032 Zürich, Switzerland
- Present address: Institute of Bioengineering and Nanotechnology, The Nanos, 138669, Singapore
| | - Beat Thöny
- Division of Clinical Chemistry and Biochemistry, Department of Pediatrics, University of Zürich, CH-8032 Zürich, Switzerland
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Bouchlariotou S, Tsikouras P, Maroulis G. Undiagnosed maternal phenylketonuria: own clinical experience and literature review. J Matern Fetal Neonatal Med 2010; 22:943-8. [PMID: 19557660 DOI: 10.1080/14767050902994697] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Phenylketonuria (PKU) is an autosomal recessive inborn error of phenylalanine (Phe) metabolism resulting from deficiency of phenylalanine hydroxylase (PAH). Most forms of PKU are caused by mutations in the PAH gene. Untreated PKU is associated with an abnormal phenotype, which includes growth failure, seizures, global developmental delay and severe intellectual impairment. The maternal PKU (MPKU) syndrome is caused by high blood Phe concentrations during pregnancy and presents with serious foetal anomalies, especially microcephaly, congenital heart disease and mental retardation. However, since the introduction of newborn screening programs and with early dietary intervention, children born with PKU can now expect to lead relatively normal lives. We present the case of a 33-year-old woman who had been diagnosed as having PKU only after a pregnancy with MPKU embryopathy, to emphasize that undiagnosed maternal phenylketonuria still exists. On that ground, we reviewed updated literature on the pathogenesis of this syndrome, possibility of prophylaxis and treatment.
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Affiliation(s)
- Sofia Bouchlariotou
- Department of Obstetrics and Gynaecology, Democritus University of Thrace, Alexandroupolis 68100, Greece
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Prasad AN, Malinger G, Lerman-Sagie T. Primary disorders of metabolism and disturbed fetal brain development. Clin Perinatol 2009; 36:621-38. [PMID: 19732617 DOI: 10.1016/j.clp.2009.06.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
There exists a link between the in utero metabolic environment and the development of the fetal nervous system. Prenatal neurosonography offers a unique, noninvasive tool in the detection of developmental brain malformations and the ability to monitor changes over time. This article explores the association of malformations of cerebral development reported in association with inborn errors of metabolism, and speculates on potential mechanisms by which such malformations arise. The detection of cerebral malformations prenatally should lead to a search for both genetic etiologies and inborn errors of metabolism in the fetus. Improving the changes of an early diagnosis provides for timely therapeutic interventions and it is hoped a brighter future for affected children and their families.
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Affiliation(s)
- Asuri N Prasad
- Section of Clinical Neurosciences, Department of Pediatrics and Child Health, Children's Hospital of Western Ontario, London Health Sciences Centre, University of Western Ontario, B-509, 800 Commissioners Road East, London, Ontario, N6C4G5, Canada
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28
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Santillan DA, Santillan MK, Hunter SK. Cell encapsulation as a potential nondietary therapy for maternal phenylketonuria. Am J Obstet Gynecol 2009; 201:289.e1-6. [PMID: 19631922 DOI: 10.1016/j.ajog.2009.05.035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2009] [Revised: 04/27/2009] [Accepted: 05/20/2009] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The objective of this work was to determine whether cells overexpressing phenylalanine (Phe) hydroxylase (PAH) can significantly reduce Phe in vitro for potential use as a therapy for preventing maternal phenylketonuria. STUDY DESIGN Human 293T and WRL68 cell lines were transiently and stably transfected to overexpress PAH. Cells were encapsulated within microspheres of sodium alginate. Timed measurements of Phe in media were performed using tandem mass spectrometry. RESULTS Both nonencapsulated and encapsulated transiently transfected cells overexpressing PAH significantly reduced the Phe concentration in media by approximately 50% in comparison to mock-transfected cells. Cell line clones stably expressing PAH significantly decreased the Phe concentration in the media by up to 85% compared with media alone. CONCLUSION Both unencapsulated and encapsulated cells overexpressing PAH significantly reduce Phe in vitro. Studies using phenylketonuria model mice will be important in determining the ability of our therapy to prevent the teratogenic effects of elevated maternal Phe in maternal phenylketonuria.
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Abstract
BACKGROUND Phenylketonuria is an inherited metabolic disorder characterised by an absence or deficiency of the enzyme phenylalanine hydroxylase. The aim of treatment is to lower blood phenylalanine concentrations to the recommended therapeutic range to prevent developmental delay and support normal growth. Current treatment consists of a low-phenylalanine diet in combination with a protein substitute which is free from or low in phenylalanine. Guidance regarding the use, dosage, and distribution of dosage of the protein substitute over a 24-hour period is unclear, and there is variation in recommendations among treatment centres. OBJECTIVES To assess the benefits and adverse effects of protein substitute, its dosage, and distribution of dose in children and adults with phenylketonuria who are adhering to a low-phenylalanine diet. SEARCH STRATEGY We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register which consists of references identified from comprehensive electronic database searches and hand searches of relevant journals and abstract books of conference proceedings. We also contacted manufacturers of the phenylalanine-free and low-phenylalanine protein substitutes for any data from published and unpublished randomised controlled trials.Date of the most recent search of the Group's Trials Register: April 2008. SELECTION CRITERIA All randomised or quasi-randomised controlled trials comparing: any dose of protein substitute with no protein substitute; an alternative dosage; or the same dose, but given as frequent small doses throughout the day compared with the same total daily dose given as larger boluses less frequently. DATA COLLECTION AND ANALYSIS Both authors independently extracted data and assessed trial quality. MAIN RESULTS Three trials (69 participants) are included in this review. One trial investigated the use of protein substitute in 16 participants, while a further two trials investigated the dosage of protein substitute in a total of 53 participants. Due to issues with data presentation in each trial, described in full in the review, formal statistical analyses of the data were impossible. Investigators are being contacted for further information. AUTHORS' CONCLUSIONS No conclusions could be drawn about the short- or long-term use of protein substitute in phenylketonuria due to the lack of adequate or analysable trial data. Additional data and randomised controlled trials are needed to investigate the use of protein substitute in phenylketonuria. Until further evidence is available, current practice in the use of protein substitute should continue to be monitored with care.
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Affiliation(s)
- Sarah H L Yi
- Graduate Program in Nutrition & Health Sciences of the Graduate Division of Biological and Biomedical Sciences, Emory University, 2165 North Decatur Road, Decatur, Georgia 30033, USA
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30
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Hanley WB. Finding the fertile woman with phenylketonuria. Eur J Obstet Gynecol Reprod Biol 2008; 137:131-5. [DOI: 10.1016/j.ejogrb.2007.12.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2007] [Revised: 10/08/2007] [Accepted: 12/23/2007] [Indexed: 11/29/2022]
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Abstract
Phenylketonuria (PKU) is an inborn error of metabolism affecting approximately one in every 10,000 infants born in Europe and the USA. Unless treated with a phenylalanine-restricted diet beginning in infancy, PKU can be associated with mental retardation, seizures, eczema and other symptoms. Treatment prevents the most severe consequences of PKU, but compliance with the strict dietary regimen is poor, especially in adolescents and adults. Despite the decline in IQ and increased emotional problems associated with poor adherence to the diet, few novel advances in treatments for PKU have occurred since 1963, when it became the first condition for which newborn screening was available. Sparked in part by acceptance of the policy of lifelong dietary treatment, alternative therapies are being investigated. These include innovations in production of low-protein foods, psychosocial interventions, new medications, enzyme therapy and perhaps even gene therapy in the future.
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Affiliation(s)
- Jennifer Gentile
- Harvard Medical School, Division of Genetics, Children’s Hospital, 1 Autumn Street, Room 526, Boston, MA 02115, USA
| | - Matthew R Fickie
- Harvard-Partners Center for Genetics & Genomics, 77 Avenue Louis Pasteur, NRB Room 250, Boston, MA 02115, USA
| | - Susan Waisbren
- Harvard Medical School, Division of Genetics, Children’s Hospital, 1 Autumn Street, Room 526, Boston, MA 02115, USA
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Ding Z, Harding CO, Rebuffat A, Elzaouk L, Wolff JA, Thöny B. Correction of murine PKU following AAV-mediated intramuscular expression of a complete phenylalanine hydroxylating system. Mol Ther 2008; 16:673-81. [PMID: 18362925 DOI: 10.1038/mt.2008.17] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Phenylketonuria (PKU) caused by phenylalanine hydroxylase (PAH) deficiency leads to toxic accumulation of phenylalanine (Phe). PAH is predominantly expressed in liver and its activity requires a supply of tetrahydrobiopterin (BH(4)) cofactor, but we propose that expression of a complete Phe hydroxylating system (PAH plus BH(4) synthetic enzymes) in skeletal muscle will lead to therapeutic reduction of blood Phe levels in Pah(enu2) mice, a model of human PKU. In order to test this hypothesis, we first developed transgenic Pah(enu2) mice that lack liver PAH activity but coexpress, in their skeletal muscle, PAH and guanosine triphosphate cyclohydrolase I (GTPCH). The latter is responsible for the committing enzymatic step in BH(4) biosynthesis. Despite sufficient muscle enzyme expression, these mice remained hyperphenylalaninemic, thereby suggesting that expression of additional BH(4) synthetic enzymes would be necessary. A recombinant triple-cistronic adeno-associated virus-2 (AAV2) pseudotype 1 vector expressing PAH along with GTPCH and 6-pyruvoyltetrahydrobiopterin synthase (PTPS), the next step in BH(4) synthesis, was generated. Injection of this vector into the gastrocnemius muscles of Pah(enu2) mice led to stable and long-term reduction of blood Phe and reversal of PKU-associated coat hypopigmentation. We propose that muscle-directed gene therapy will be a viable alternative treatment approach to PKU and other inborn errors of metabolism.
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Affiliation(s)
- Zhaobing Ding
- Division of Clinical Chemistry and Biochemistry, Department of Pediatrics, University of Zürich, Zürich, Switzerland
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Innes AM. Molecular genetic testing and genetic counseling. HANDBOOK OF CLINICAL NEUROLOGY 2008; 87:517-531. [PMID: 18809042 DOI: 10.1016/s0072-9752(07)87028-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Affiliation(s)
- A Micheil Innes
- Department of Medical Genetics, University of Calgary, Alberta Children's Hospital, 1888 Shaganappi Trail NW, Calgary, Alberta, Canada.
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Abstract
Phenylketonuria (PKU) was first described over 70 years ago, treatment was developed 50 years ago and universal newborn PKU screening was introduced 40 years ago. Phenylalanine-restricted dietary treatment has prevented mental retardation in thousands of individuals worldwide. We acknowledge, however, that there is still much to learn in the field. The incidence of mental retardation in untreated PKU is likely to be considerably less than the original estimates. Since dietary control is suboptimal in late childhood, adolescence and adulthood, alternative methods of treatment are being explored. These include large neutral amino acids, phenylalanine ammonia lyase, tetrahydrobiopterin and gene replacement. Evidence has surfaced that the semisynthetic, low-protein diet used to treat PKU may be deficient in certain important nutrients. Maternal PKU treatment may be successful even if initiated as late as 8-10 weeks into pregnancy. A plea is made for the immediate establishment of adult treatment centers for PKU (and other inherited metabolic diseases) for long-term treatment, follow-up and research.
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Affiliation(s)
- W B Hanley
- a The Hospital for Sick Children and the Faculty of Medicine, University of Toronto, Division of Clinical & Biochemical Genetics, Department of Paediatrics, 555 University Ave, Toronto, ON M5G 1X8, Canada.
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Abstract
Mental retardation (MR) is a manifestation of a heterogeneous set of impairments and conditions that result in cognitive limitation. It is a condition of medical, educational, and social importance. Physicians identify profound, severe, and moderate MR but rarely diagnose mild MR unless it is associated with a genetic or medical syndrome. From a medical perspective, the quest for etiology and the possibility of medical or surgical intervention to minimize deterioration are paramount. Educators, on the other hand are less concerned with causation than with academic achievement and school success. The majority of cases of mild MR is identified in school settings. Finally, the public uses the label to describe poor adaptive skills. Adults with MR who hold jobs, live independently, and participate in society are not always described as having MR. Thus some individuals characterized in childhood or adolescence as having mild MR become indistinguishable from the general population in adulthood.
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Guizzetti M, Costa LG. Disruption of cholesterol homeostasis in the developing brain as a potential mechanism contributing to the developmental neurotoxicity of ethanol: an hypothesis. Med Hypotheses 2005; 64:563-7. [PMID: 15617867 DOI: 10.1016/j.mehy.2004.05.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2004] [Accepted: 05/19/2004] [Indexed: 11/28/2022]
Abstract
While excess cholesterol may have deleterious consequences, as in the case of atherosclerosis, too little cholesterol may endanger the development of the brain. Different degrees of mental retardation are often observed in inborn errors of cholesterol synthesis, such as the Smith-Lemli-Opitz syndrome or in maternal phenylketonuria, where the metabolite of accumulating phenylalanine, phenylacetate, is an inhibitor of cholesterol synthesis. Lack of cholesterol during brain development as a consequence of these genetic defects leads to severe brain damage, microencephaly and mental retardation, which are also hallmarks of the fetal alcohol syndrome (FAS). The brain relies on the in situ synthesis of cholesterol, which occurs mostly in astrocytes. Astrocyte-produced cholesterol is utilized for cell proliferation, or is released, via astrocyte-secreted high density lipoprotein-like particles containing apolipoprotein E, outside the cell, where it is taken up and utilized by neurons for dendrite outgrowth and to form synapses. We propose the hypothesis that ethanol may disrupt cholesterol homeostasis during brain development, and that this effect may be responsible, at least in part, for the central nervous system dysfunctions observed in the FAS, which include altered astrocyte proliferation, neuronal death and diminished synaptic contacts.
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Affiliation(s)
- Marina Guizzetti
- Department of Environmental and Occupational Health Sciences, School of Public Health and Community Medicine, Toxicology Program, University of Washington, Seattle, WA 98105, USA.
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Antshel KM, Waisbren SE. Developmental timing of exposure to elevated levels of phenylalanine is associated with ADHD symptom expression. JOURNAL OF ABNORMAL CHILD PSYCHOLOGY 2004; 31:565-74. [PMID: 14658738 DOI: 10.1023/a:1026239921561] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This study addresses attention deficit hyperactivity disorder (ADHD), with a focus on how the timing of a known biological insult affects ADHD symptom expression. The sample consists of children exposed to elevated levels of phenylalanine, either postnatally as in Phenylketonuria (PKU; n = 46) or prenatally as in Maternal PKU (MPKU; n = 15). Non-hyperphenylalaninemic siblings of children with PKU (n = 18) serve as controls. Results indicate that elevated levels of phenylalanine are associated with ADHD symptoms. The manifestations of the symptom expression are dependent on exposure timing: prenatal exposure is associated with a higher likelihood of expressing hyperactive/impulsive symptoms and postnatal exposure is associated with a higher likelihood of expressing inattentive symptoms. This toxicity is dose-dependent and higher levels of phenylalanine appear more detrimental.
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Affiliation(s)
- Kevin M Antshel
- Children's Hospital-Boston, Division of Psychology, Department of Psychiatry, Harvard Medical School, Longwood Avenue, Boston, Massachusetts, USA.
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39
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Abstract
Untreated pregnancies and their outcomes were studied in 10 women with histidinaemia and their 26 pregnancies. The mean maternal assigned histidine level was 727+/-186 micromol/L (range 484-1,053). Six women had classic histidinaemia (assigned level >700 micromol/L) and the remaining four had mild (atypical) histidinaemia. The pregnancies were uneventful, with only one spontaneous loss and 25 live births. Birth measurements were normal and no congenital anomalies were observed. Growth and development were normal in all offspring. IQ among the 23 offspring tested was 103+/-12 (range 79-122). Four offspring required special education for brief periods and one for several years, but this frequency, as well as that of 12% for attention deficit hyperactive disorder, was not significantly different from expected in the general population. It would appear that maternal histidinaemia, unlike maternal phenylketonuria, can be added to the list of maternal inborn errors of metabolism that are nonteratogenic.
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Affiliation(s)
- H L Levy
- Genetic Services, Children's Hospital Boston, Massachusetts 02115, USA.
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Hanley WB, Azen C, Koch R, Michals-Matalon K, Matalon R, Rouse B, Trefz F, Waisbren S, de la Cruz F. Maternal Phenylketonuria Collaborative Study (MPKUCS)--the 'outliers'. J Inherit Metab Dis 2004; 27:711-23. [PMID: 15505376 DOI: 10.1023/b:boli.0000045758.86492.54] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Analysis of outcome data from 305 of the 414 offspring from the Maternal Phenylketonuria Collaborative Study (MPKUCS), plus 70 control offspring, revealed significant deficits in the IQ (intelligence quotient), as measured by the Wechsler Intelligence Scale for Children--Revised (WISC-R), when maternal metabolic control during pregnancy was delayed and/or inadequate. There were, however, 23 'outliers' (7.5% of the 305) in which the offspring's intellectual IQ was worse (n =10) or better (n =13) than expected. The aim of this study was to determine whether collection parameters were incomplete or whether these subjects were true biological variants influenced by other undetected factors or, perhaps, by modifier genes. Among the 10 offspring whose intellectual functioning was worse than expected, additional complications were uncovered that could explain the poor outcome. Four of the 13 offspring with higher than expected IQ had mothers with mild variants of PKU in which the insult to the fetus would not be expected to be as profound. For the other nine offspring whose intellectual performance was better than expected, there was no explanation, based on the parameters studied. We hypothesize that modifier genes will, at times, protect the fetus despite high maternal concentrations of phenylalanine. Not all offspring from the same (untreated) PKU mother may be similarly affected. Finding the source of these modifiers might effect the treatment of MPKU.
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Affiliation(s)
- W B Hanley
- PKU Programme, Hospital for Sick Children, Toronto, Ontario, Canada.
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41
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Antshel KM, Waisbren SE. Timing is everything: executive functions in children exposed to elevated levels of phenylalanine. Neuropsychology 2003; 17:458-68. [PMID: 12959512 DOI: 10.1037/0894-4105.17.3.458] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
This study addresses how the timing of a known biological insult affects the developmental progression of executive functions. The sample consisted of children exposed to elevated levels of phenylalanine, either postnatally, as in phenylketonuria (PKU; n = 46), or prenatally, as in maternal PKU (n = 15). Nonhyperphenylanemic siblings of children with PKU (n = 18) served as controls. Results indicated that elevated levels of phenylalanine are toxic to the neurological systems that manage executive functions and cognitive tempo. This toxicity is dose dependent, with higher levels of phenylalanine being more detrimental. Executive function difficulties noted in PKU are consistent with attention deficit hyperactivity disorder (ADHD)-inattentive type, whereas maternal PKU offspring had executive function difficulties consistent with ADHD-combined type.
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Affiliation(s)
- Kevin M Antshel
- Department of Psychiatry, Children's Hospital--Boston and Harvard Medical School, USA.
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Postlethwaite D. Preconception health counseling for women exposed to teratogens: the role of the nurse. J Obstet Gynecol Neonatal Nurs 2003; 32:523-32. [PMID: 12903703 DOI: 10.1177/0884217503255373] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Women with unintended pregnancies who are exposed to teratogens constitute the highest risk group for fetal harm. Teratogen exposures come from substances, medications, chronic and acute diseases, and environmental factors. Nurses play a critical role in reducing unintended pregnancy and promoting preconception health. A greater understanding of the role of teratogens and strategies to improve history taking and help women prevent unintended pregnancy will improve nurses' ability to reduce teratogen exposure in women at risk.
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Mudd SH, Tangerman A, Stabler SP, Allen RH, Wagner C, Zeisel SH, Levy HL. Maternal methionine adenosyltransferase I/III deficiency: reproductive outcomes in a woman with four pregnancies. J Inherit Metab Dis 2003; 26:443-58. [PMID: 14518826 DOI: 10.1023/a:1025121326959] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Four pregnancies in a women with moderately severe deficiency of methionine adenosyltransferase I/III (MAT I/III) activity are reported. She is an apparent homozygote for a point mutation in MAT1A, the gene that encodes the catalytically active subunit of MAT I/III. This mutation reduces the activity of her expressed enzyme to some 11% of wild-type. She was the first such individual identified in the United States, and these are the first pregnancies known in anyone with this extent of MAT I/III deficiency. No adverse effects were noted in the mother. Three normal babies resulted, but fetal arrest was detected in one embryo at 10-11 weeks gestation. Plasma methionine concentrations remained virtually constant at their elevated levels of 300-350 micromol/L throughout the pregnancies. Plasma free choline was below the reference range. In view of the evidence that maternal choline delivery to the fetus is important for brain development, it was suggested the patient ingest two eggs daily from gestation week 17. Plasma choline and phosphatidylcholine tended to rise during such supplementation. Plasma cystathionine concentrations rose progressively to far above normal during these pregnancies, but not during pregnancies in control women. This may be explained by delivery of excessive methionine to the fetus, with consequent increased cystathionine synthesis by fetal tissues. Because fetal tissues lack gamma-cystathionase, presumably cystathionine accumulated abnormally in the fetus and was transferred in abnormal amounts back to the mother. Plasma and urinary concentrations of methionine transamination metabolites rose during pregnancy for reasons that remain obscure.
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Affiliation(s)
- S H Mudd
- Laboratory of Molecular Biology, National Institute of Mental Health, DIRP, Bethesda, Maryland 20892-4034, USA.
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45
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Antshel KM, Gurian EA, Waisbren SE. Maternal phenylketonuria: a case study suggesting the use of prenatal psychotherapy to help control phenylalanine levels. THE AMERICAN JOURNAL OF ORTHOPSYCHIATRY 2002; 72:577-584. [PMID: 15792042 DOI: 10.1037/0002-9432.72.4.577] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Maternal phenylketonuria (MPKU) is an increasingly common concern for health professionals involved in prenatal care. This single-participant study investigated the efficacy of prenatal psychotherapy in improving metabolic control, an important consideration in MPKU pregnancies. Results indicated a robust and positive relationship between psychotherapy and metabolic control. Levels of negative mood and levels of phenylalanine control were also strongly and positively correlated. Implications for treating MPKU are discussed, and prenatal psychotherapy is forwarded as a means of improving birth outcomes in this population.
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Affiliation(s)
- Kevin M Antshel
- Department of Psychiatry, Children's Hospital Boston, Boston, Massachusetts, USA.
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46
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Costa LG, Guizzetti M, Burry M, Oberdoerster J. Developmental neurotoxicity: do similar phenotypes indicate a common mode of action? A comparison of fetal alcohol syndrome, toluene embryopathy and maternal phenylketonuria. Toxicol Lett 2002; 127:197-205. [PMID: 12052659 DOI: 10.1016/s0378-4274(01)00501-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Developmental neurotoxicity can be ascribed to in utero exposure to exogenous substances or to exposure of the fetus to endogenous compounds that accumulate because of genetic mutations. One of the best recognized human neuroteratogens is ethanol. The Fetal Alcohol Syndrome (FAS) is characterized by growth deficiency, particular facial features, and central nervous system (CNS) dysfunctions (mental retardation, microencephaly and brain malformations). Abuse of toluene by pregnant women can lead to an embryopathy (fetal solvent syndrome, (FSS)) whose characteristics are similar to FAS. Phenylketonuria (PKU) is a genetic defect in phenylalanine (Phe) metabolism. Offspring of phenylketonuric mothers not under strict dietary control are born with maternal PKU (mPKU), a syndrome with similar characteristics as FAS and FSS. While ethanol has been shown to cause neuronal death, no such evidence is available for toluene or Phe and/or its metabolites. On the other hand, alterations in astrocyte proliferation and maturation have been found, mostly in in vitro studies, which may represent a potential common mode of action for at least some of the CNS effects found in FAS, mPKU, and FSS. Further in vivo and in vitro studies should validate this hypothesis and elucidate possible molecular targets.
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Affiliation(s)
- L G Costa
- Toxicology Program, University of Washington, 4225 Roosevelt Way NE, #100, Seattle 98105-6099, USA.
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47
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Levy HL, Guldberg P, Güttler F, Hanley WB, Matalon R, Rouse BM, Trefz F, Azen C, Allred EN, de la Cruz F, Koch R. Congenital heart disease in maternal phenylketonuria: report from the Maternal PKU Collaborative Study. Pediatr Res 2001; 49:636-42. [PMID: 11328945 DOI: 10.1203/00006450-200105000-00005] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The frequency and types of congenital heart disease in offspring from pregnancies in women with hyperphenylalaninemia were examined in the international prospective Maternal Phenylketonuria Collaborative Study. Relationships of congenital heart disease in offspring to the basal blood phenylalanine level in the mother, metabolic control through diet during pregnancy, and phenylalanine hydroxylase mutations in mother and offspring were determined. The 416 offspring from 412 maternal phenylketonuria pregnancies that produced live births and 100 offspring from the 99 control pregnancies were included in this examination. Thirty-four of the 235 offspring (14%; 95% CI, 10.2 to 19.6%) from pregnancies in phenylketonuric women with a basal phenylalanine level > or = 900 microM (15 mg/dL) [normal blood phenylalanine < 120 microM (2 mg/dL)] and not in metabolic control [phenylalanine level < or = 600 microM (10 mg/dL)] by the eighth gestational week had congenital heart disease compared with one control offspring (1%) with congenital heart disease. One offspring among the 50 (2%) from mothers with non-phenylketonuria mild hyperphenylalaninemia also had congenital heart disease. Coarctation of the aorta and hypoplastic left heart syndrome were overrepresented compared with expected percentages among those with congenital heart disease in the general population. A basal maternal phenylalanine level > 1800 microM (30 mg/dL) significantly increased the risk for bearing a child with congenital heart disease (p = 0.003). Phenylalanine hydroxylase mutations in the mothers and offspring did not have an independent relationship to congenital heart disease but were related through the basal maternal phenylalanine levels. The data in this study indicate that a basal maternal phenylalanine level of 900 microM may be a threshold for congenital heart disease, that women with the most severe degree of phenylketonuria are at highest risk for bearing such a child, and that prevention of the congenital heart disease requires initiation of the low phenylalanine diet before conception or early in pregnancy with metabolic control no later than the eighth gestational week.
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Affiliation(s)
- H L Levy
- Division of Genetics and Neuroepidemiology Unit, Children's Hospital, Boston, Massachusetts 02115, USA.
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48
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Infante JP, Huszagh VA. Impaired arachidonic (20:4n-6) and docosahexaenoic (22:6n-3) acid synthesis by phenylalanine metabolites as etiological factors in the neuropathology of phenylketonuria. Mol Genet Metab 2001; 72:185-98. [PMID: 11243724 DOI: 10.1006/mgme.2001.3148] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The recent literature on polyunsaturated fatty acid metabolism in phenylketonuria (PKU) is critically analyzed. The data suggest that developmental impairment of the accretion of brain arachidonic (20:4n-6) and docosahexaenoic (22:6n-3, DHA) acids is a major etiological factor in the microcephaly and mental retardation of uncontrolled PKU and maternal PKU. These fatty acids appear to be synthesized by the recently elucidated carnitine-dependent, channeled, mitochondrial fatty acid desaturases for which alpha-tocopherolquinone (alpha-TQ) is an essential enzyme cofactor. alpha-TQ can be synthesized either de novo or from alpha-tocopherol. The fetus and newborn would primarily rely on de novo alpha-TQ synthesis for these mitochondrial desaturases because of low maternal transfer of alpha-tocopherol. Homogentisate, a pivotal intermediate in the de novo pathway of alpha-TQ synthesis, is synthesized by 4-hydroxyphenylpyruvate dioxygenase. The major catabolic products of excess phenylalanine, viz. phenylpyruvate and phenyllactate, are proposed to inhibit alpha-TQ synthesis at the level of the dioxygenase reaction by competing with its 4-hydroxyphenylpyruvate substrate, thus leading to a developmental impairment of 20:4n-6 and 22:6n-3 synthesis in uncontrolled PKU and fetuses of PKU mothers. The data suggest that dietary supplementation with carnitine, 20:4n-6, and 22:6n-3 may have therapeutic value for PKU mothers and for PKU patients who have been shown to have a low plasma status of these essential metabolites.
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Affiliation(s)
- J P Infante
- Institute for Theoretical Biochemistry and Molecular Biology, Ithaca, New York 14852, USA.
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49
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Abstract
Diet has long been recognized as the primary treatment modality for individuals with phenylketonuria (PKU) during infancy and childhood. Recent findings from the Maternal PKU Collaborative Study clearly indicate that dietary restriction of phenylalanine is also necessary to prevent the adverse effects of an elevated plasma phenylalanine concentration during pregnancy, which include microcephaly, physical anomalies, and mental retardation.
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Affiliation(s)
- N F Sheard
- Department of Nutrition & Food Sciences, University of Vermont, Burlington 05405, USA
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50
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Abstract
BeWo choriocarcinoma cells were cultured onto solid microcarrier beads, packed into columns and superfused. Unidirectional influx of l -phenylalanine (l -phe) and l -leucine (l -leu) across the microvillous border of the cells was studied using a rapid paired-tracer dilution technique. Influx of l -phe and l -leu comprised both saturable and non-saturable components. K(m)values for l -phe and l -leu were 0.57+/-0.01 m m and 0.05+/-0.01 m m, respectively, with V(max)values of 120.4+/-0.5 nmol/mg/min and 41. 7+/-0.2 nmol/mg/min. Non-saturable uptake components were 29.0+/-0.1 nmol/mg/m m and 37.9+/-0.1 nmol/mg/min/m m respectively. l -leu uptake was found to be sodium-independent. The uptake of l -[(3)H]phe was strongly inhibited (90-100 per cent) by unlabelled l -phe, d -phe, l -leu or 2-aminoendobicyclo-[2,2, 1]-heptane-2-carboxylic acid (BCH) but not by l -arginine (l -arg) or methyl alpha-aminoisobutric acid (Me-AIB). Pre-incubation of Bewo cultures for 24 h in the presence of an additional 1.2 m ml -phe (simulating maternal phenylketonuria) significantly reduced both the K(m)and V(max)components of l -phe influx. l -arg (2 m m) had no effect on l -leu influx whereas 2 m ml -phe completely inhibited saturable l -leu influx. These data suggest that the microvillous border of differentiated BeWo cells transport large neutral amino acids predominantly via system L rather than by B(0) or y(+)L transporters.
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Affiliation(s)
- B M Eaton
- Department of Maternal and Fetal Medicine, Imperial College School of Medicine, Chelsea and Westminster Hospital, London, UK.
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