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Vonada A, Wakefield L, Martinez M, Harding CO, Grompe M, Tiyaboonchai A. Complete correction of murine phenylketonuria by selection-enhanced hepatocyte transplantation. Hepatology 2024; 79:1088-1097. [PMID: 37824086 DOI: 10.1097/hep.0000000000000631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 09/18/2023] [Indexed: 10/13/2023]
Abstract
BACKGROUND AND AIMS Hepatocyte transplantation for genetic liver diseases has several potential advantages over gene therapy. However, the low efficiency of cell engraftment has limited its clinical implementation. This problem could be overcome by selectively expanding transplanted donor cells until they replace enough of the liver mass to achieve therapeutic benefit. We previously described a gene therapy method to selectively expand hepatocytes deficient in cytochrome p450 reductase (Cypor) using acetaminophen (APAP). Because Cypor is required for the transformation of APAP to a hepatotoxic metabolite, Cypor-deficient cells are protected from toxicity and are able to expand following APAP-induced liver injury. Here, we apply this selection system to correct a mouse model of phenylketonuria by cell transplantation. APPROACH AND RESULTS Hepatocytes from a wild-type donor animal were edited in vitro to create Cypor deficiency and then transplanted into phenylketonuric animals. Following selection with APAP, blood phenylalanine concentrations were fully normalized and remained stable following APAP withdrawal. Cypor-deficient hepatocytes expanded from < 1% to ~14% in corrected animals, and they showed no abnormalities in blood chemistries, liver histology, or drug metabolism. CONCLUSIONS We conclude that APAP-mediated selection of transplanted hepatocytes is a potential therapeutic for phenylketonuria with long-term efficacy and a favorable safety profile.
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Affiliation(s)
- Anne Vonada
- Oregon Stem Cell Center, Oregon Health & Science University, Portland, Oregon, USA
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, Oregon, USA
| | - Leslie Wakefield
- Oregon Stem Cell Center, Oregon Health & Science University, Portland, Oregon, USA
- Department of Pediatrics, Oregon Health & Science University, Portland, Oregon, USA
| | - Michael Martinez
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, Oregon, USA
| | - Cary O Harding
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, Oregon, USA
- Department of Pediatrics, Oregon Health & Science University, Portland, Oregon, USA
| | - Markus Grompe
- Oregon Stem Cell Center, Oregon Health & Science University, Portland, Oregon, USA
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, Oregon, USA
- Department of Pediatrics, Oregon Health & Science University, Portland, Oregon, USA
| | - Amita Tiyaboonchai
- Oregon Stem Cell Center, Oregon Health & Science University, Portland, Oregon, USA
- Department of Pediatrics, Oregon Health & Science University, Portland, Oregon, USA
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2
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Deng IB, Follett J, Bu M, Farrer MJ. DNAJC12 in Monoamine Metabolism, Neurodevelopment, and Neurodegeneration. Mov Disord 2024; 39:249-258. [PMID: 38014588 DOI: 10.1002/mds.29677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 10/04/2023] [Accepted: 11/09/2023] [Indexed: 11/29/2023] Open
Abstract
Recent studies show that pathogenic variants in DNAJC12, a co-chaperone for monoamine synthesis, may cause mild hyperphenylalaninemia with infantile dystonia, young-onset parkinsonism, developmental delay and cognitive deficits. DNAJC12 has been included in newborn screening, most revealingly in Spain, and those results highlight the importance of genetic diagnosis and early intervention in combating human disease. However, practitioners may be unaware of these advances and it is probable that many patients, especially adults, have yet to receive molecular testing for DNAJC12. Hence, this review summarizes genotype-phenotype relationships and treatment paradigms for patients with pathogenic variants in DNAJC12. It provides an overview of the structure of DNAJC12 protein, known genetic variants, domains, and binding partners, and elaborates on its role in monoamine synthesis, disease etiology, and pathogenesis. © 2023 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Isaac Bul Deng
- Department of Neurology, University of Florida, Gainesville, Florida, USA
| | - Jordan Follett
- Department of Neurology, University of Florida, Gainesville, Florida, USA
| | - Mengfei Bu
- Department of Neurology, University of Florida, Gainesville, Florida, USA
| | - Matthew J Farrer
- Department of Neurology, University of Florida, Gainesville, Florida, USA
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3
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Manek R, Zhang YV, Berthelette P, Hossain M, Cornell CS, Gans J, Anarat-Cappillino G, Geller S, Jackson R, Yu D, Singh K, Ryan S, Bangari DS, Xu EY, Kyostio-Moore SRM. Blood phenylalanine reduction reverses gene expression changes observed in a mouse model of phenylketonuria. Sci Rep 2021; 11:22886. [PMID: 34819582 PMCID: PMC8613214 DOI: 10.1038/s41598-021-02267-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 11/09/2021] [Indexed: 12/02/2022] Open
Abstract
Phenylketonuria (PKU) is a genetic deficiency of phenylalanine hydroxylase (PAH) in liver resulting in blood phenylalanine (Phe) elevation and neurotoxicity. A pegylated phenylalanine ammonia lyase (PEG-PAL) metabolizing Phe into cinnamic acid was recently approved as treatment for PKU patients. A potentially one-time rAAV-based delivery of PAH gene into liver to convert Phe into tyrosine (Tyr), a normal way of Phe metabolism, has now also entered the clinic. To understand differences between these two Phe lowering strategies, we evaluated PAH and PAL expression in livers of PAHenu2 mice on brain and liver functions. Both lowered brain Phe and increased neurotransmitter levels and corrected animal behavior. However, PAL delivery required dose optimization, did not elevate brain Tyr levels and resulted in an immune response. The effect of hyperphenylalanemia on liver functions in PKU mice was assessed by transcriptome and proteomic analyses. We observed an elevation in Cyp4a10/14 proteins involved in lipid metabolism and upregulation of genes involved in cholesterol biosynthesis. Majority of the gene expression changes were corrected by PAH and PAL delivery though the role of these changes in PKU pathology is currently unclear. Taken together, here we show that blood Phe lowering strategy using PAH or PAL corrects both brain pathology as well as previously unknown lipid metabolism associated pathway changes in liver.
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Affiliation(s)
- Rachna Manek
- Genomic Medicine Unit, Sanofi, Framingham, MA, USA.
| | - Yao V Zhang
- Genomic Medicine Unit, Sanofi, Framingham, MA, USA
| | | | | | | | - Joseph Gans
- Translational Sciences, Sanofi, Framingham, MA, USA
| | | | - Sarah Geller
- Pre-Development Sciences NA, Analytical R&D, Sanofi, Framingham, MA, USA
| | | | - Dan Yu
- Genomic Medicine Unit, Sanofi, Framingham, MA, USA
| | - Kuldeep Singh
- Global Discovery Pathology, Sanofi, Framingham, MA, USA
| | - Sue Ryan
- Global Discovery Pathology, Sanofi, Framingham, MA, USA
| | | | - Ethan Y Xu
- Translational Sciences, Sanofi, Framingham, MA, USA
- Excision BioTherapeutics, Cambridge, MA, USA
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4
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Khani S, Barzegari M, Esmaeilizadeh Z, Farsian P, Alaei M, Salehpour S, Setoodeh A, Rohani F, Samavat A, Zekri A, Mirzazadeh R, Sadeghi S, Khatami S. The treatment and clinical follow-up outcome in Iranian patients with tetrahydrobiopterin deficiency. J Pediatr Endocrinol Metab 2021; 34:1157-1167. [PMID: 34214291 DOI: 10.1515/jpem-2021-0155] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 05/12/2021] [Indexed: 11/15/2022]
Abstract
OBJECTIVES This study aimed to evaluate the biochemical factors, genetic mutations, outcome of treatment, and clinical follow-up data of Iranian patients with tetrahydrobiopterin (BH4) deficiency from April/2016 to March/2020. METHODS Forty-seven BH4 deficiency patients were included in the study and underwent biochemical and genetic analyses. The clinical outcomes of the patients were evaluated after long-term treatment. RESULTS Out of the 47 (25 females and 22 males) BH4 deficiency patients enrolled in the study, 23 were Dihydropteridine reductase (DHPR) deficient patients, 23 were 6-pyruvoyl-tetrahydropterin synthase (PTPS) deficient patients, and one was GTP-Cyclohydrolase 1 deficiency (GTPCH-1) patient. No clinical symptoms were observed in 10 of the DHPR deficient patients (before and after the treatment). Also, most patients diagnosed at an early age had a proper response to the treatment. However, drug therapy did not improve clinical symptoms in three of the patients diagnosed at the age of over 10 years. Also, 16 PTPS deficiency patients who were detected within 6 months and received treatment no clinical symptoms were presented. One of the patients was detected with GTPCH deficiency. Despite being treated with BH4, this patient suffered from a seizure, movement disorder, mental retardation, speech difficulty, and hypotonia. CONCLUSIONS The study results showed that neonatal screening should be carried out in all patients with hyperphenylalaninemia because early diagnosis and treatment can reduce symptoms and prevent neurological impairments. Although the BH4 deficiency outcomes are highly variable, early diagnosis and treatment in the first months of life are crucial for good outcomes.
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Affiliation(s)
- Soghra Khani
- Department of Biochemistry, Pasteur Institute of Iran, Tehran, Iran
| | - Mina Barzegari
- Department of Biochemistry, Pasteur Institute of Iran, Tehran, Iran
| | | | - Pantea Farsian
- Department of Biochemistry, Pasteur Institute of Iran, Tehran, Iran
| | - Mohammadreza Alaei
- Mofid Children's Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Shadab Salehpour
- Genomic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Aria Setoodeh
- Growth and Development Research Center, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Farzaneh Rohani
- Department of Pediatrics Endocrinology and Metabolism, Ali Asghar Children's Hospital, Iran University of Medical Sciences, Tehran, Iran
| | - Ashraf Samavat
- Genetics Office, CDC, Ministry of Health of Iran, Tehran, Iran
| | - Ali Zekri
- Department of Medical Genetics and Molecular Biology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | | | - Sedigheh Sadeghi
- Department of Biochemistry, Pasteur Institute of Iran, Tehran, Iran
| | - Shohreh Khatami
- Department of Biochemistry, Pasteur Institute of Iran, Tehran, Iran
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5
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Lopez A, Havranek B, Papadantonakis GA, Islam SM. In silico screening and molecular dynamics simulation of deleterious PAH mutations responsible for phenylketonuria genetic disorder. Proteins 2021; 89:683-696. [PMID: 33491267 DOI: 10.1002/prot.26051] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 01/08/2021] [Accepted: 01/21/2021] [Indexed: 12/23/2022]
Abstract
Phenylketonuria (PKU) is a genetic disorder that if left untreated can lead to behavioral problems, epilepsy, and even mental retardation. PKU results from mutations within the phenylalanine-4-hydroxylase (PAH) gene that encodes for the PAH protein. The study of all PAH causing mutations is improbable using experimental techniques. In this study, a collection of in silico resources, sorting intolerant from tolerant, Polyphen-2, PhD-SNP, and MutPred were used to identify possible pathogenetic and deleterious PAH non-synonymous single nucleotide polymorphisms (nsSNPs). We identified two variants of PAH, I65N and L311P, to be the most deleterious and disease causing nsSNPs. Molecular dynamics (MD) simulations were carried out to characterize these point mutations on the atomic level. MD simulations revealed increased flexibility and a decrease in the hydrogen bond network for both mutants compared to the native protein. Free energy calculations using the MM/GBSA approach found that BH4 , a drug-based therapy for PKU patients, had a higher binding affinity for I65N and L311P mutants compared to the wildtype protein. We also identify important residues in the BH4 binding pocket that may be of interest for the rational drug design of other PAH drug-based therapies. Lastly, free energy calculations also determined that the I65N mutation may impair the dimerization of the N-terminal regulatory domain of PAH.
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Affiliation(s)
- Andrea Lopez
- Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Brandon Havranek
- Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois, USA
| | | | - Shahidul M Islam
- Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois, USA
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6
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Himmelreich N, Blau N, Thöny B. Molecular and metabolic bases of tetrahydrobiopterin (BH 4) deficiencies. Mol Genet Metab 2021; 133:123-136. [PMID: 33903016 DOI: 10.1016/j.ymgme.2021.04.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 04/09/2021] [Accepted: 04/09/2021] [Indexed: 01/01/2023]
Abstract
Tetrahydrobiopterin (BH4) deficiency is caused by genetic variants in the three genes involved in de novo cofactor biosynthesis, GTP cyclohydrolase I (GTPCH/GCH1), 6-pyruvoyl-tetrahydropterin synthase (PTPS/PTS), sepiapterin reductase (SR/SPR), and the two genes involved in cofactor recycling, carbinolamine-4α-dehydratase (PCD/PCBD1) and dihydropteridine reductase (DHPR/QDPR). Dysfunction in BH4 metabolism leads to reduced cofactor levels and may result in systemic hyperphenylalaninemia and/or neurological sequelae due to secondary deficiency in monoamine neurotransmitters in the central nervous system. More than 1100 patients with BH4 deficiency and 800 different allelic variants distributed throughout the individual genes are tabulated in database of pediatric neurotransmitter disorders PNDdb. Here we provide an update on the molecular-genetic analysis and structural considerations of these variants, including the clinical courses of the genotypes. From a total of 324 alleles, 11 are associated with the autosomal recessive form of GTPCH deficiency presenting with hyperphenylalaninemia (HPA) and neurotransmitter deficiency, 295 GCH1 variant alleles are detected in the dominant form of L-dopa-responsive dystonia (DRD or Segawa disease) while phenotypes of 18 alleles remained undefined. Autosomal recessive variants observed in the PTS (199 variants), PCBD1 (32 variants), and QDPR (141 variants) genes lead to HPA concomitant with central monoamine neurotransmitter deficiency, while SPR deficiency (104 variants) presents without hyperphenylalaninemia. The clinical impact of reported variants is essential for genetic counseling and important for development of precision medicine.
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Affiliation(s)
- Nastassja Himmelreich
- Center for Child and Adolescent Medicine, Dietmar-Hopp Metabolic Center, Division 1, Heidelberg, Germany
| | - Nenad Blau
- Division of Metabolism, University Children's Hospital Zürich, Zürich, Switzerland.
| | - Beat Thöny
- Division of Metabolism and Children's Research Centre, University Children's Hospital Zürich, Zürich, Switzerland.
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7
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van Wegberg A, Evers R, Burgerhof J, van Dam E, Heiner-Fokkema MR, Janssen M, de Vries MC, van Spronsen FJ. Effect of BH4 on blood phenylalanine and tyrosine variations in patients with phenylketonuria. Mol Genet Metab 2021; 133:49-55. [PMID: 33766497 DOI: 10.1016/j.ymgme.2021.02.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 02/26/2021] [Accepted: 02/26/2021] [Indexed: 02/06/2023]
Abstract
BACKGROUND In patients with phenylketonuria, stability of blood phenylalanine and tyrosine concentrations might influence brain chemistry and therefore patient outcome. This study prospectively investigated the effects of tetrahydrobiopterin (BH4), as a chaperone of phenylalanine hydroxylase on diurnal and day-to-day variations of blood phenylalanine and tyrosine concentrations. METHODS Blood phenylalanine and tyrosine were measured in dried blood spots (DBS) four times daily for 2 days (fasting, before lunch, before dinner, evening) and once daily (fasting) for 6 days in a randomized cross-over design with a period with BH4 and a period without BH4. The sequence was randomized. Eleven proven BH4 responsive PKU patients participated, 5 of them used protein substitutes during BH4 treatment. Natural protein intake and protein substitute dosing was adjusted during the period without BH4 in order to keep DBS phenylalanine levels within target range. Patients filled out a 3-day food diary during both study periods. Variations of DBS phenylalanine and Tyr were expressed in standard deviations (SD) and coefficient of variation (CV). RESULTS BH4 treatment did not significantly influence day-to-day phenylalanine and tyrosine variations nor diurnal phenylalanine variations, but decreased diurnal tyrosine variations (median SD 17.6 μmol/l, median CV 21.3%, p = 0.01) compared to diet only (median SD 34.2 μmol/l, median CV 43.2%). Consequently, during BH4 treatment diurnal phenylalanine/tyrosine ratio variation was smaller, while fasting tyrosine levels tended to be higher. CONCLUSION BH4 did not impact phenylalanine variation but decreased diurnal tyrosine and phenylalanine/tyrosine ratio variations, possibly explained by less use of protein substitute and increased tyrosine synthesis.
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Affiliation(s)
- Amj van Wegberg
- Division of Metabolic Diseases, Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, the Netherlands
| | - Raf Evers
- Division of Metabolic Diseases, Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, the Netherlands
| | - Jgm Burgerhof
- Department of Epidemiology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - E van Dam
- Division of Metabolic Diseases, Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, the Netherlands
| | - M R Heiner-Fokkema
- Department of Laboratory Medicine, Laboratory of Metabolic Diseases, University of Groningen, University Medical Centre Groningen, the Netherlands
| | - McH Janssen
- Department of Internal Medicine, Radboudumc, Nijmegen, the Netherlands
| | - M C de Vries
- Department of Pediatrics, Radboudumc Nijmegen, the Netherlands
| | - F J van Spronsen
- Division of Metabolic Diseases, Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, the Netherlands.
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Gundorova P, Kuznetcova IA, Baydakova GV, Stepanova AA, Itkis YS, Kakaulina VS, Alferova IP, Lyazina LV, Andreeva LP, Kanivets I, Zakharova EY, Kutsev SI, Polyakov AV. BH4-deficient hyperphenylalaninemia in Russia. PLoS One 2021; 16:e0249608. [PMID: 33822819 PMCID: PMC8023510 DOI: 10.1371/journal.pone.0249608] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 03/22/2021] [Indexed: 02/07/2023] Open
Abstract
A timely detection of patients with tetrahydrobiopterin (BH4) -deficient types of hyperphenylalaninemia (HPABH4) is important for assignment of correct therapy, allowing to avoid complications. Often HPABH4 patients receive the same therapy as phenylalanine hydroxylase (PAH) -deficiency (phenylketonuria) patients—dietary treatment—and do not receive substitutive BH4 therapy until the diagnosis is confirmed by molecular genetic means. In this study, we present a cohort of 30 Russian patients with HPABH4 with detected variants in genes causing different types of HPA. Family diagnostics and biochemical urinary pterin spectrum analyses were carried out. HPABH4A is shown to be the prevalent type, 83.3% of all HPABH4 cases. The mutation spectrum for the PTS gene was defined, the most common variants in Russia were p.Thr106Met—32%, p.Asn72Lys—20%, p.Arg9His—8%, p.Ser32Gly—6%. We also detected 7 novel PTS variants and 3 novel QDPR variants. HPABH4 prevalence was estimated to be 0.5–0.9% of all HPA cases in Russia, which is significantly lower than in European countries on average, China, and Saudi Arabia. The results of this research show the necessity of introducing differential diagnostics for HPABH4 into neonatal screening practice.
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Affiliation(s)
| | | | | | | | | | - Victoria S. Kakaulina
- Federal State Budgetary Institution of Medical Department of Moscow “Morozov Children’s City Clinical Hospital of Medical Department of Moscow”, Moscow, Russia
| | - Irina P. Alferova
- Municipal Autonomous Health Care Institution of the Order of the Red Banner of Labor “Clinical Hospital № 1”, Chelyabinsk, Russia
| | - Lidya V. Lyazina
- Saint Petersburg State Public Health Institution "Medical Genetic Diagnostic Center”, Saint Petersburg, Russia
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9
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Evers RAF, van Wegberg AMJ, Ahring K, Beblo S, Bélanger-Quintana A, Bosch AM, Burlina A, Campistol J, Coskun T, Feillet F, Giżewska M, Huijbregts SCJ, Kearney S, Langeveld M, Leuzzi V, Maillot F, Muntau AC, Rocha JC, Romani C, Trefz FK, MacDonald A, van Spronsen FJ. Defining tetrahydrobiopterin responsiveness in phenylketonuria: Survey results from 38 countries. Mol Genet Metab 2021; 132:215-219. [PMID: 33610470 DOI: 10.1016/j.ymgme.2021.01.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/28/2021] [Accepted: 01/29/2021] [Indexed: 11/21/2022]
Abstract
BACKGROUND A subset of patients with phenylketonuria benefit from treatment with tetrahydrobiopterin (BH4), although there is no consensus on the definition of BH4 responsiveness. The aim of this study therefore was to gain insight into the definitions of long-term BH4 responsiveness being used around the world. METHODS We performed a web-based survey targeting healthcare professionals involved in the treatment of PKU patients. Data were analysed according to geographical region (Europe, USA/Canada, other). RESULTS We analysed 166 responses. Long-term BH4 responsiveness was commonly defined using natural protein tolerance (95.6%), improvement of metabolic control (73.5%) and increase in quality of life (48.2%). When a specific value for a reduction in phenylalanine concentrations was reported (n = 89), 30% and 20% were most frequently used as cut-off values (76% and 19% of respondents, respectively). When a specific relative increase in natural protein tolerance was used to define long-term BH4 responsiveness (n = 71), respondents most commonly reported cut-off values of 30% and 100% (28% of respondents in both cases). Respondents from USA/Canada (n = 50) generally used less strict cut-off values compared to Europe (n = 96). Furthermore, respondents working within the same center answered differently. CONCLUSION The results of this study suggest a very heterogeneous situation on the topic of defining long-term BH4 responsiveness, not only at a worldwide level but also within centers. Developing a strong evidence- and consensus-based definition would improve the quality of BH4 treatment.
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Affiliation(s)
- R A F Evers
- University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Division of Metabolic Diseases, the Netherlands
| | - A M J van Wegberg
- University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Division of Metabolic Diseases, the Netherlands
| | - K Ahring
- Department of PKU, Copenhagen University Hospital, Denmark
| | - S Beblo
- Center for Pediatric Research Leipzig, Department of Women and Child Health, Hospital for Children and Adolescents, University Hospitals, Germany
| | - A Bélanger-Quintana
- Metabolic Diseases Unit, Department of Pediatrics, Hospital Ramon y Cajal, Madrid, Spain
| | - A M Bosch
- Department of Pediatrics, Division of Metabolic Disorders, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - A Burlina
- Division of Inherited Metabolic Diseases, Department of Integrated Diagnostics, University Hospital of Padova, Padova, Italy
| | - J Campistol
- Neuropaediatrics Department, Hospital Sant Joan de Déu, University of Barcelona, Barcelona, Spain
| | - T Coskun
- Hacettepe University Faculty of Medicine, Department of Pediatrics, Division of Pediatric Nutrition & Metabolism, Hacettepe, Ankara, Turkey
| | - F Feillet
- Inborn Errors of Metabolism, Pediatric unit, University Hospital of Nancy, INSERM UMR_S 1256, Nutrition, Genetics, and Environmental Risk Exposure (NGERE), Nancy, France
| | - M Giżewska
- Department of Pediatrics, Endocrinology, Diabetology, Metabolic Diseases and Cardiology of the Developmental Age, Pomeranian Medical University, Szczecin, Poland
| | - S C J Huijbregts
- Department of Clinical Child and Adolescent Studies-Neurodevelopmental Disorders, Faculty of Social Sciences, Leiden University, Leiden, Netherlands
| | - S Kearney
- Clinical Psychology Department, Birmingham Children's Hospital, Birmingham, UK
| | - M Langeveld
- Department of Endocrinology and Metabolism, Amterdam UMC, University of Amsterdam, AZ, Amsterdam, the Netherlands
| | - V Leuzzi
- Department of Human Neuroscience, Unit of Child Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy
| | - F Maillot
- Department of Internal Medicine, CHRU de Tours, Université de Tours, Tours, France
| | - A C Muntau
- University Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - J C Rocha
- Centro de Referência na área de Doenças Hereditárias do Metabolismo, Centro Hospitalar Universitário do Porto - CHUP, Porto, Portugal; Centre for Health Technology and Services Research (CINTESIS), Portugal; Nutrition & Metabolism, Nova Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
| | - C Romani
- School of Life and Health Sciences, Aston University, Birmingham, UK
| | - F K Trefz
- University Children's Hospital, Dietmar-Hoppe Metabolic Centre, Heidelberg, Germany
| | - A MacDonald
- Dietetic Department, Birmingham Children's Hospital, Birmingham, UK
| | - F J van Spronsen
- University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Division of Metabolic Diseases, the Netherlands.
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10
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Dobrowolski SF, Sudano C, Phua YL, Tourkova IL, Spridik K, Goetzman ES, Vockley J, Blair HC. Mesenchymal stem cell energy deficit and oxidative stress contribute to osteopenia in the Pah enu2 classical PKU mouse. Mol Genet Metab 2021; 132:173-179. [PMID: 33602601 PMCID: PMC9795491 DOI: 10.1016/j.ymgme.2021.01.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/25/2021] [Accepted: 01/26/2021] [Indexed: 12/31/2022]
Abstract
Osteopenia occurs in a subset of phenylalanine hydroxylase (PAH) deficient phenylketonuria (PKU) patients. While osteopenia is not fully penetrant in patients, the Pahenu2 classical PKU mouse is universally osteopenic, making it an ideal model of the phenotype. Pahenu2 Phe management, with a Phe-fee amino acid defined diet, does not improve bone density as histomorphometry metrics remain indistinguishable from untreated animals. Previously, we demonstrated Pahenu2 mesenchymal stem cells (MSCs) display impaired osteoblast differentiation. Oxidative stress is recognized in PKU patients and PKU animal models. Pahenu2 MSCs experience oxidative stress determined by intracellular superoxide over-representation. The deleterious impact of oxidative stress on mitochondria is recognized. Oximetry applied to Pahenu2 MSCs identified mitochondrial stress by increased basal respiration with concurrently reduced maximal respiration and respiratory reserve. Proton leak secondary to mitochondrial complex 1 dysfunction is a recognized superoxide source. Respirometry applied to Pahenu2 MSCs, in the course of osteoblast differentiation, identified a partial complex 1 deficit. Pahenu2 MSCs treated with the antioxidant resveratrol demonstrated increased mitochondrial mass by MitoTracker green labeling. In hyperphenylalaninemic conditions, resveratrol increased in situ alkaline phosphatase activity suggesting partial recovery of Pahenu2 MSCs osteoblast differentiation. Up-regulation of oxidative energy production is required for osteoblasts differentiation. Our data suggests impaired Pahenu2 MSC developmental competence involves an energy deficit. We posit energy support and oxidative stress reduction will enable Pahenu2 MSC differentiation in the osteoblast lineage to subsequently increase bone density.
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Affiliation(s)
- Steven F Dobrowolski
- Department of Pathology, University of Pittsburgh, School of Medicine, Pittsburgh, PA 15224, United States of America.
| | - Cayla Sudano
- Department of Pathology, University of Pittsburgh, School of Medicine, Pittsburgh, PA 15224, United States of America
| | - Yu Leng Phua
- Division of Medical Genetics, Children's Hospital of Pittsburgh, Pittsburgh, PA 15224, United States of America
| | - Irina L Tourkova
- Department of Pathology, University of Pittsburgh, School of Medicine, Pittsburgh, PA 15224, United States of America; Pittsburgh Veteran's Affairs Medical Center, Pittsburgh, PA 15261, United States of America
| | - Kayla Spridik
- Department of Pathology, University of Pittsburgh, School of Medicine, Pittsburgh, PA 15224, United States of America
| | - Eric S Goetzman
- Division of Medical Genetics, Children's Hospital of Pittsburgh, Pittsburgh, PA 15224, United States of America
| | - Jerry Vockley
- Division of Medical Genetics, Children's Hospital of Pittsburgh, Pittsburgh, PA 15224, United States of America
| | - Harry C Blair
- Department of Pathology, University of Pittsburgh, School of Medicine, Pittsburgh, PA 15224, United States of America; Pittsburgh Veteran's Affairs Medical Center, Pittsburgh, PA 15261, United States of America
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11
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Clocksin HE, Hawks ZW, White DA, Christ SE. Inter- and intra-tract analysis of white matter abnormalities in individuals with early-treated phenylketonuria (PKU). Mol Genet Metab 2021; 132:11-18. [PMID: 33334682 DOI: 10.1016/j.ymgme.2020.12.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 12/02/2020] [Accepted: 12/02/2020] [Indexed: 11/22/2022]
Abstract
Even with early and continuous treatment, individuals with phenylketonuria (PKU) may exhibit abnormalities of cortical white matter (WM). The present study utilizes a new analysis approach called Automated Fiber-Tract Quantification (AFQ) to advance our understanding of the tract-specific patterns of change in WM abnormalities in individuals with early-treated PKU (ETPKU). Diffusion Tensor Imaging (DTI) data from a sample of 22 individuals with ETPKU and a demographically-matched sample of 21 healthy individuals without PKU was analyzed using AFQ. In addition, a subsample of 8 individuals with ETPKU was reevaluated six months later after demonstrating a significant reduction in blood phe levels following initiation of sapropterin treatment. Within-tract AFQ analyses revealed significant location-by-group interactions for several WM tracts throughout the brain. In most cases, ETPKU-related disruptions in mean diffusivity (MD) were more apparent in posterior (as compared to anterior) aspects of a given tract. Reduction in blood phe levels with the aforementioned ETPKU subsample was associated with a similar pattern of improvement (posterior-to-anterior) within most tracts. Taken together, these findings suggest that there is a systematic pattern of change in WM abnormalities in individuals with ETPKU in a posterior-to-anterior manner along individual WM tracts.
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Affiliation(s)
- Hayley E Clocksin
- Department of Psychological Sciences, University of Missouri, Columbia, MO, 65211, USA
| | - Zoë W Hawks
- Department of Psychological and Brain Sciences, Washington University in St. Louis, St. Louis, MO, 63130, USA
| | - Desirée A White
- Department of Psychological and Brain Sciences, Washington University in St. Louis, St. Louis, MO, 63130, USA
| | - Shawn E Christ
- Department of Psychological Sciences, University of Missouri, Columbia, MO, 65211, USA.
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12
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Manzoni F, Salvatici E, Burlina A, Andrews A, Pasquali M, Longo N. Retrospective analysis of 19 patients with 6-Pyruvoyl Tetrahydropterin Synthase Deficiency: Prolactin levels inversely correlate with growth. Mol Genet Metab 2020; 131:380-389. [PMID: 33234470 PMCID: PMC7749858 DOI: 10.1016/j.ymgme.2020.11.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 11/10/2020] [Accepted: 11/11/2020] [Indexed: 11/27/2022]
Abstract
BACKGROUND Pyruvoyl Tetrahydropterin Synthase (PTPS) Deficiency is the most common form of BH4 deficiency resulting in hyperphenylalaninemia. It can have variable clinical severity and there is limited information on the clinical presentation, natural history and effectiveness of newborn screening for this condition. METHODS Retrospective data (growth and clinical parameters, biochemical and genetic testing results, treatment) were collected from 19 patients with PTPS deficiency in different centers, to evaluate biochemical and clinical outcomes. Descriptive statistics was used for qualitative variables, while linear regression analysis was used to correlate quantitative variables. RESULTS Patients with PTPS deficiency had an increased incidence of prematurity (4/18) with an average gestational age only mildly reduced (37.8 ± 2.4 weeks) and low birth weight (-1.14 ± 0.97 SD below that predicted for gestational age). With time, weight and height approached normal. VALUES All patients were identified by newborn screening for an elevated phenylalanine level. However, phenylalanine levels were normal in two whose testing was performed at or before 24 h of age. Sapropterin dihydrochloride treatment normalized phenylalanine levels. Molecular testing identified novel variants in the PTS gene, some of which present in more than one affected family. The neurotransmitter derivatives 5-hydroxyindoleacetic acid (5HIAA) and homovanillic acid (HVA) in the CSF were decreased in most cases except in 2 families with the peripheral form of PTPS deficiency. With time, HVA and 5HIAA became abnormally low in two of these patients requiring therapy. Prolactin (whose secretion is inhibited by dopamine) levels were elevated in several patients with PTPS deficiency and inversely correlated with the z-scores for height (p < 0.01) and weight (p < 0.05). Most patients with PTPS deficiency had delayed development early in life, improving around school age with IQs mostly in the normal range, with a small decline in older individuals. From a neurological standpoint, most patients had normal brain MRI and minor EEG anomalies, although some had persistent neurological symptoms. DISCUSSION Patients with PTPS deficiency have not only an increased incidence of prematurity, but also decreased birth weight when corrected for gestational age. Hyperphenylalaninemia can be absent in the first day of life. Therapy with sapropterin dihydrochloride normalizes phenylalanine levels and neurotransmitter precursors can improve CSF neurotransmitter metabolites levels. Insufficient dopaminergic stimulation (as seen from elevated prolactin) might result in decreased height in patients with PTPS deficiency. Despite early delays in development, many patients can achieve independence in adult life, with usually normal neuroimaging and EEG.
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Affiliation(s)
- Francesca Manzoni
- Division of Medical Genetics/Pediatrics, University of Utah, Salt Lake City, UT, USA; Clinical Department of Neuropsychiatry, San Paolo Hospital, University of Milan, Milan, Italy; Division of Inherited Metabolic Diseases, Department of Diagnostic Services, University Hospital, Padua, Italy
| | - Elisabetta Salvatici
- Clinical Department of Pediatrics, San Paolo Hospital, University of Milan, Milan, Italy
| | - Alberto Burlina
- Division of Inherited Metabolic Diseases, Department of Diagnostic Services, University Hospital, Padua, Italy
| | - Ashley Andrews
- Division of Medical Genetics/Pediatrics, University of Utah, Salt Lake City, UT, USA
| | - Marzia Pasquali
- Division of Medical Genetics/Pediatrics, University of Utah, Salt Lake City, UT, USA; ARUP Laboratories, Salt Lake City, UT, USA; Department of Pathology, University of Utah, Salt Lake City, UT, USA
| | - Nicola Longo
- Division of Medical Genetics/Pediatrics, University of Utah, Salt Lake City, UT, USA; ARUP Laboratories, Salt Lake City, UT, USA; Department of Pathology, University of Utah, Salt Lake City, UT, USA..
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13
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Richards DY, Winn SR, Dudley S, Fedorov L, Rimann N, Thöny B, Harding CO. A novel Pah-exon1 deleted murine model of phenylalanine hydroxylase (PAH) deficiency. Mol Genet Metab 2020; 131:306-315. [PMID: 33051130 PMCID: PMC8173763 DOI: 10.1016/j.ymgme.2020.09.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 09/16/2020] [Accepted: 09/23/2020] [Indexed: 12/26/2022]
Abstract
Phenylalanine hydroxylase (PAH) deficiency, colloquially known as phenylketonuria (PKU), is among the most common inborn errors of metabolism and in the past decade has become a target for the development of novel therapeutics such as gene therapy. PAH deficient mouse models have been key to new treatment development, but all prior existing models natively express liver PAH polypeptide as inactive or partially active PAH monomers, which complicates the experimental assessment of protein expression following therapeutic gene, mRNA, protein, or cell transfer. The mutant PAH monomers are able to form hetero-tetramers with and inhibit the overall holoenzyme activity of wild type PAH monomers produced from a therapeutic vector. Preclinical therapeutic studies would benefit from a PKU model that completely lacks both PAH activity and protein expression in liver. In this study, we employed CRISPR/Cas9-mediated gene editing in fertilized mouse embryos to generate a novel mouse model that lacks exon 1 of the Pah gene. Mice that are homozygous for the Pah exon 1 deletion are viable, severely hyperphenylalaninemic, accurately replicate phenotypic features of untreated human classical PKU and lack any detectable liver PAH activity or protein. This model of classical PKU is ideal for further development of gene and cell biologics to treat PKU.
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Affiliation(s)
- Daelyn Y Richards
- Department of Medical and Molecular Genetics, Oregon Health & Science University, Portland, USA
| | - Shelley R Winn
- Department of Medical and Molecular Genetics, Oregon Health & Science University, Portland, USA
| | - Sandra Dudley
- Department of Medical and Molecular Genetics, Oregon Health & Science University, Portland, USA
| | - Lev Fedorov
- Transgenic Mouse Models Core, Oregon Health and Science University, Portland, USA
| | - Nicole Rimann
- Division of Metabolism, University Children's Hospital, Steinweissstrasse 75, Zurich CH-8032, Switzerland
| | - Beat Thöny
- Division of Metabolism, University Children's Hospital, Steinweissstrasse 75, Zurich CH-8032, Switzerland
| | - Cary O Harding
- Department of Medical and Molecular Genetics, Oregon Health & Science University, Portland, USA.
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14
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Manti F, Nardecchia F, Banderali G, Burlina A, Carducci C, Carducci C, Donati MA, Gueraldi D, Paci S, Pochiero F, Porta F, Ortolano R, Rovelli V, Schiaffino MC, Spada M, Blau N, Leuzzi V. Long-term clinical outcome of 6-pyruvoyl-tetrahydropterin synthase-deficient patients. Mol Genet Metab 2020; 131:155-162. [PMID: 32651154 DOI: 10.1016/j.ymgme.2020.06.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 06/17/2020] [Accepted: 06/18/2020] [Indexed: 12/14/2022]
Abstract
INTRODUCTION 6-Pyruvoyl-tetrahydropterin synthase deficiency (PTPSd) is a rare autosomal recessive disorder of synthesis of biogenic amines, which is characterized by variable neurological impairment and hyperphenylalaninemia. We aimed to assess the long-term clinical outcome of this disorder and the factors affecting it. METHODS At total of 28 PTPSd patients (aged 19.9 ± 10.9 years) underwent clinical (neurological and psychiatric) and neuropsychological assessment (BRIEF, VABS-II, and IQ). Based on CSF homovanillic (HVA) and 5-hydroxyindolacetic acid (5-HIAA) and pterin concentrations at diagnosis, patients were classified as having either a severe [SF; low level of CSF, HVA, and 5-HIAA with altered neopterin/biopterin (Neo/Bio)] or mild form (MF; normal HVA and 5-HIAA with altered Neo/Bio) of PTPSd. RESULTS Approximately 36% of patients had MF PTPSd. At the last examination, 43% of patients had movement disorders (2 MF, 10 SF), 43% of patients had variable degrees of intellectual disability (SF only), 39% met the criteria for a psychiatric disorder (3 MF, 9 SF). Applying a linear regression model, we found that HVA and phenylalanine levels at birth had a significant influence on IQ, BRIEF, and VABS-II variability. Lastly, 5-HIAA further contributed to VABS-II variability. The disease showed a self-limiting clinical course and its treatment, although delayed, is effective in improving the neurological status. CONCLUSIONS Neurodevelopmental impairment due to PTPSd shows a self-limiting course. A continuous improvement in the neurological condition has been observed in patients receiving treatment, even when delayed. The severity of brain biogenic amine depletion at diagnosis predicts neurological and psychiatric outcomes.
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Affiliation(s)
- Filippo Manti
- Department of Human Neuroscience, Unit of Child Neurology and Psychiatry, Sapienza University, Rome, Italy
| | - Francesca Nardecchia
- Department of Human Neuroscience, Unit of Child Neurology and Psychiatry, Sapienza University, Rome, Italy
| | - Giuseppe Banderali
- Department of Pediatrics, University of Milan, San Paolo Hospital, Santi Paolo e Carlo ASST, Milan, Italy
| | - Alberto Burlina
- Division of Inherited Metabolic Diseases, Department of Paediatrics, University Hospital of Padova, Padova, Italy
| | - Carla Carducci
- Department of Experimental Medicine, Sapienza University of Rome, Italy
| | - Claudia Carducci
- Department of Experimental Medicine, Sapienza University of Rome, Italy
| | | | - Daniela Gueraldi
- Division of Inherited Metabolic Diseases, Department of Paediatrics, University Hospital of Padova, Padova, Italy
| | - Sabrina Paci
- Department of Pediatrics, University of Milan, San Paolo Hospital, Santi Paolo e Carlo ASST, Milan, Italy
| | | | - Francesco Porta
- Department of Pediatrics, AOU Città della Salute e della Scienza di Torino, University of Torino, Italy
| | - Rita Ortolano
- Department of Medical and Surgical Sciences, Pediatric Unit, Regional Centre for Expanded Newborn Screening, S. Orsola-Malpighi University Hospital, Bologna, Italy
| | - Valentina Rovelli
- Department of Pediatrics, University of Milan, San Paolo Hospital, Santi Paolo e Carlo ASST, Milan, Italy
| | | | - Marco Spada
- Department of Pediatrics, AOU Città della Salute e della Scienza di Torino, University of Torino, Italy
| | - Nenad Blau
- Division of Metabolism, University Children's Hospital Zürich, Switzerland
| | - Vincenzo Leuzzi
- Department of Human Neuroscience, Unit of Child Neurology and Psychiatry, Sapienza University, Rome, Italy.
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15
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Burton BK, Longo N, Vockley J, Grange DK, Harding CO, Decker C, Li M, Lau K, Rosen O, Larimore K, Thomas J. Pegvaliase for the treatment of phenylketonuria: Results of the phase 2 dose-finding studies with long-term follow-up. Mol Genet Metab 2020; 130:239-246. [PMID: 32593547 DOI: 10.1016/j.ymgme.2020.06.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 05/08/2020] [Accepted: 06/11/2020] [Indexed: 01/28/2023]
Abstract
BACKGROUND Phenylketonuria (PKU) is characterized by a deficiency in phenylalanine hydroxylase (PAH) that may lead to elevated blood phenylalanine (Phe) and significant neurocognitive and neuropsychological comorbidities. Pegvaliase (PALYNZIQ®, BioMarin Pharmaceutical Inc.) is a PEGylated recombinant Anabaena variabilis phenylalanine ammonia lyase (PAL), which converts Phe to trans-cinnamic acid and ammonia, and was approved in May 2018 in the United States and in May 2019 in the European Union for decreasing blood Phe levels in adults with PKU with blood Phe levels >600 μmol/L. The efficacy and safety of pegvaliase was assessed in two phase 2 dose-finding studies in adults with PKU (PAL-002, NCT00925054, and PAL-004, NCT01212744). Participants completing these studies could enroll in a long-term extension study (PAL-003, NCT00924703). METHODS Participants in PAL-002 received pegvaliase 0.001, 0.003, 0.01, 0.03, or 0.1 mg/kg weekly for 8 weeks, then continued treatment for a further 8 weeks with dose and/or frequency adjusted to achieve blood Phe concentrations of 60 to 600 μmol/L. Participants in PAL-004 received pegvaliase 0.001 to 0.4 mg/kg 5 days/week for 13 weeks, with modifications made to the starting dose in response to safety and/or efficacy, followed by 3 additional weeks of follow-up assessments. The maximum allowable daily dose in both studies was 1.0 mg/kg/day (5.0 mg/kg/week). Participants who completed any of the phase 2 studies (PAL-002; PAL-004; or a third phase 2 study, 165-205) were eligible to enroll in an open-label, multicenter, long-term extension study (PAL-003, NCT00924703). RESULTS Thirty-seven of the 40 enrolled participants completed PAL-002 and 15 of the 16 enrolled participants completed PAL-004. Mean blood Phe at baseline was 1311.0 (standard deviation [SD] 354) μmol/L in PAL-002 and 1482.1 (SD 363.5) μmol/L in PAL-004. Mean blood Phe did not substantially decrease with pegvaliase treatment in PAL-002 (-206.3 [SD 287.1] μmol/L at Week 16) or PAL-004 (-410.8 [SD 653.7] μmol/L at Week 13). In PAL-004, mean blood Phe dropped from baseline by 929.1 μmol/L (SD 691.1) by Week 2; subsequent to dose modifications and interruptions, this early decrease in mean Phe level was not sustained. With increased pegvaliase dose and duration in PAL-003, mean blood Phe levels steadily decreased from baseline, with mean reductions by Week 120 of 68.8% (SD 44.2%) in PAL-002 participants and 75.9% (SD 32.4%) in PAL-004 participants. All participants in PAL-002 and PAL-004 reported ≥1 adverse event (AE), with higher exposure-adjusted event rates in PAL-004. The majority of AEs were mild (87.2% in PAL-002, 86.7% in PAL-004) or moderate (12.4% in PAL-002, 13.3% in PAL-004). The most commonly reported AEs in PAL-002 were injection site reaction (50.0% of participants), headache (42.1%), injection site erythema (36.8%), nausea (34.2%), and arthralgia (29.0%), and in PAL-004 were arthralgia (75.0%), headache (62.5%), dizziness (56.3%), injection site erythema (56.3%), and injection site reaction (50.0%). CONCLUSIONS In two phase 2 dose-finding studies, pegvaliase did not lead to substantial blood Phe reductions. Higher and more frequent pegvaliase dosing in PAL-004 led to a substantial initial drop in blood Phe, but an increase in the number of hypersensitivity AEs and dose reductions or interruptions. With increased dose and duration of treatment in PAL-003, mean blood Phe reduction was substantial and sustained, and the frequency of hypersensitivity AEs decreased and stabilized. Together, these studies led to the development of an induction-titration-maintenance regimen that has been approved for pegvaliase, with patients starting at a low weekly dose that gradually increases in dose and frequency until they achieve a standard non-weight-based daily maintenance dose. This regimen has been tested in a third phase 2 study, as well as in two successful phase 3 studies of pegvaliase.
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Affiliation(s)
- Barbara K Burton
- Department of Pediatrics, Division of Genetics, Birth Defects & Metabolism, Ann & Robert H. Lurie Children's Hospital of Chicago, 225 E Chicago Ave, Chicago, IL 60611, United States of America.
| | - Nicola Longo
- Department of Pediatrics, Division of Medical Genetics, University of Utah, 295 Chipeta Way, Salt Lake City, UT 84108, United States of America.
| | - Jerry Vockley
- Department of Pediatrics, Division of Medical Genetics, University of Pittsburgh and Children's Hospital of Pittsburgh, 4401 Penn Ave, Pittsburgh, PA 15224, United States of America.
| | - Dorothy K Grange
- Department of Pediatrics, Division of Genetics and Genomic Medicine, Washington University, 660 S Euclid Ave, St. Louis, MO 63110, United States of America.
| | - Cary O Harding
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR 97239, United States of America.
| | - Celeste Decker
- Research and Development, BioMarin Pharmaceutical Inc., 105 Digital Dr, Novato, CA 94949, United States of America
| | - Mingjin Li
- Research and Development, BioMarin Pharmaceutical Inc., 105 Digital Dr, Novato, CA 94949, United States of America.
| | - Kelly Lau
- Research and Development, BioMarin Pharmaceutical Inc., 105 Digital Dr, Novato, CA 94949, United States of America.
| | - Orli Rosen
- Research and Development, BioMarin Pharmaceutical Inc., 105 Digital Dr, Novato, CA 94949, United States of America.
| | - Kevin Larimore
- Research and Development, BioMarin Pharmaceutical Inc., 105 Digital Dr, Novato, CA 94949, United States of America.
| | - Janet Thomas
- Department of Pediatrics, Section of Clinical Genetics and Metabolism, University of Colorado School of Medicine, 12605 E 16th St, Aurora, CO 80045, United States of America.
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16
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Sarodaya N, Suresh B, Kim KS, Ramakrishna S. Protein Degradation and the Pathologic Basis of Phenylketonuria and Hereditary Tyrosinemia. Int J Mol Sci 2020; 21:ijms21144996. [PMID: 32679806 PMCID: PMC7404301 DOI: 10.3390/ijms21144996] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 07/10/2020] [Accepted: 07/13/2020] [Indexed: 12/15/2022] Open
Abstract
A delicate intracellular balance among protein synthesis, folding, and degradation is essential to maintaining protein homeostasis or proteostasis, and it is challenged by genetic and environmental factors. Molecular chaperones and the ubiquitin proteasome system (UPS) play a vital role in proteostasis for normal cellular function. As part of protein quality control, molecular chaperones recognize misfolded proteins and assist in their refolding. Proteins that are beyond repair or refolding undergo degradation, which is largely mediated by the UPS. The importance of protein quality control is becoming ever clearer, but it can also be a disease-causing mechanism. Diseases such as phenylketonuria (PKU) and hereditary tyrosinemia-I (HT1) are caused due to mutations in PAH and FAH gene, resulting in reduced protein stability, misfolding, accelerated degradation, and deficiency in functional proteins. Misfolded or partially unfolded proteins do not necessarily lose their functional activity completely. Thus, partially functional proteins can be rescued from degradation by molecular chaperones and deubiquitinating enzymes (DUBs). Deubiquitination is an important mechanism of the UPS that can reverse the degradation of a substrate protein by covalently removing its attached ubiquitin molecule. In this review, we discuss the importance of molecular chaperones and DUBs in reducing the severity of PKU and HT1 by stabilizing and rescuing mutant proteins.
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Affiliation(s)
- Neha Sarodaya
- Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul 04763, Korea; (N.S.); (B.S.)
| | - Bharathi Suresh
- Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul 04763, Korea; (N.S.); (B.S.)
| | - Kye-Seong Kim
- Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul 04763, Korea; (N.S.); (B.S.)
- College of Medicine, Hanyang University, Seoul 04763, Korea
- Correspondence: (K.-S.K.); or (S.R.)
| | - Suresh Ramakrishna
- Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul 04763, Korea; (N.S.); (B.S.)
- College of Medicine, Hanyang University, Seoul 04763, Korea
- Correspondence: (K.-S.K.); or (S.R.)
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Lilleväli H, Pajusalu S, Wojcik MH, Goodrich J, Collins RL, Murumets Ü, Tammur P, Blau N, Lilleväli K, Õunap K. Genome sequencing identifies a homozygous inversion disrupting QDPR as a cause for dihydropteridine reductase deficiency. Mol Genet Genomic Med 2020; 8:e1154. [PMID: 32022462 PMCID: PMC7196484 DOI: 10.1002/mgg3.1154] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 01/10/2020] [Accepted: 01/11/2020] [Indexed: 02/06/2023] Open
Abstract
Background Dihydropteridine reductase (DHPR) is one of the key enzymes for maintaining in the organism the supply of tetrahydrobiopterin (BH4), an essential cofactor for aromatic amino acid hydroxylases. Its dysfunction causes the condition of hyperphenylalaninemia together with the lack of neurotransmitters. Methods We report a patient with biochemically diagnosed DHPR deficiency, with extensive molecular investigations undertaken to detect variations in quinoid dihydropteridine reductase (QDPR) gene. Sanger sequencing of QDPR coding regions, exome sequencing, QDPR mRNA PCR, and karyotyping were followed by trio genome sequencing. Results Short‐read genome sequencing revealed a homozygous 9‐Mb inversion disrupting QDPR. Structural variant breakpoints in chromosome 4 were located to intron 2 of QDPR at Chr4(GRCh38):g.17505522 and in intron 8 of the ACOX3 gene, Chr4(GRCh38):g.8398067). Both nonrelated parents carried the variant in heterozygous state. The inversion was not present in gnomAD structural variant database. Conclusion Identification of the exact breakpoints now allows further straightforward molecular genetic testing of potential carriers of the inversion. This study extends the pathogenic variant spectrum of DHPR deficiency and highlights the role of structural variants in recessive metabolic disorders. To our knowledge, this is the first report on a large, canonical (rather than complex) homozygous pathogenic inversion detected by genome sequencing.
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Affiliation(s)
- Hardo Lilleväli
- Department of Clinical Genetics, United LaboratoriesTartu University HospitalTartuEstonia
- Institute of Biomedicine and Translational MedicineUniversity of TartuTartuEstonia
| | - Sander Pajusalu
- Department of Clinical Genetics, United LaboratoriesTartu University HospitalTartuEstonia
- Department of GeneticsYale University School of MedicineNew HavenCTUSA
- Department of Clinical GeneticsInstitute of Clinical MedicineUniversity of TartuTartuEstonia
| | - Monica H. Wojcik
- The Broad Institute of MIT and HarvardCambridgeMAUSA
- Divisions of Genetics and Genomics and Newborn MedicineDepartment of PediatricsChildren’s HospitalBostonMAUSA
| | - Julia Goodrich
- The Broad Institute of MIT and HarvardCambridgeMAUSA
- Divisions of Genetics and Genomics and Newborn MedicineDepartment of PediatricsChildren’s HospitalBostonMAUSA
| | - Ryan L. Collins
- The Broad Institute of MIT and HarvardCambridgeMAUSA
- Program in Bioinformatics and Integrative GenomicsDivision of Medical SciencesHarvard Medical SchoolBostonMAUSA
| | - Ülle Murumets
- Department of Clinical Genetics, United LaboratoriesTartu University HospitalTartuEstonia
| | - Pille Tammur
- Department of Clinical Genetics, United LaboratoriesTartu University HospitalTartuEstonia
| | - Nenad Blau
- Dietmar‐Hopp Metabolic CenterUniversity of HeidelbergHeidelbergGermany
- Division of MetabolismUniversity Children’s HospitalZürichSwitzerland
| | - Kersti Lilleväli
- Institute of Biomedicine and Translational MedicineUniversity of TartuTartuEstonia
| | - Katrin Õunap
- Department of Clinical Genetics, United LaboratoriesTartu University HospitalTartuEstonia
- Department of Clinical GeneticsInstitute of Clinical MedicineUniversity of TartuTartuEstonia
- The Broad Institute of MIT and HarvardCambridgeMAUSA
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Sergi C, Lam J, Persad R. Clostridium ventriculi Infection in a Child with Phenylketonuria. Ann Clin Lab Sci 2020; 50:134-135. [PMID: 32161022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Disabled individuals may be at risk for common and rare infections. We report on a 13-year-old female who had a diagnosis of phenylketonuria (PKU). The child received a percutaneous endoscopic gastrostomy (PEG) feeding tube at five years of age for the supplementation of her specialized formula. After eight years, she no longer required the gastrostomy tube for formula supplementation, and she presented for the closure of the gastrocutaneous fistula tract. The histological examination revealed acute and chronic inflammation and colonization by gram-positive bacteria with a characteristic tetrad packet arrangement known as Clostridium ventriculi (formerly Sarcina ventriculi). A review of the literature evidenced the rarity of this infection in children. This patient is the 11th case of such infection in literature, and the first patient affected with PKU. Physically and mentally disabled children are particularly vulnerable to infection because of their different feeding abilities, toilet needs, and sanitary arrangements.
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Affiliation(s)
- Consolato Sergi
- Department of Laboratory Medicine and Pathology, University of Alberta, Stollery Children's Hospital, Edmonton, AB, Canada
| | - Jennifer Lam
- Department of Pediatric Surgery, University of Alberta, Stollery Children's Hospital, Edmonton, AB, Canada
| | - Rabin Persad
- Department of Pediatric Gastroenterology, University of Alberta, Stollery Children's Hospital, Edmonton, AB, Canada
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Grisch-Chan HM, Schwank G, Harding CO, Thöny B. State-of-the-Art 2019 on Gene Therapy for Phenylketonuria. Hum Gene Ther 2019; 30:1274-1283. [PMID: 31364419 PMCID: PMC6763965 DOI: 10.1089/hum.2019.111] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 07/22/2019] [Indexed: 12/21/2022] Open
Abstract
Phenylketonuria (PKU) is considered to be a paradigm for a monogenic metabolic disorder but was never thought to be a primary application for human gene therapy due to established alternative treatment. However, somewhat unanticipated improvement in neuropsychiatric outcome upon long-term treatment of adults with PKU with enzyme substitution therapy might slowly change this assumption. In parallel, PKU was for a long time considered to be an excellent test system for experimental gene therapy of a Mendelian autosomal recessive defect of the liver due to an outstanding mouse model and the easy to analyze and well-defined therapeutic end point, that is, blood l-phenylalanine concentration. Lifelong treatment by targeting the mouse liver (or skeletal muscle) was achieved using different approaches, including (1) recombinant adeno-associated viral (rAAV) or nonviral naked DNA vector-based gene addition, (2) genome editing using base editors delivered by rAAV vectors, and (3) by delivering rAAVs for promoter-less insertion of the PAH-cDNA into the Pah locus. In this article we summarize the gene therapeutic attempts of correcting a mouse model for PKU and discuss the future implications for human gene therapy.
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Affiliation(s)
- Hiu Man Grisch-Chan
- Division of Metabolism, University Children's Hospital Zurich and Children's Research Centre, Zurich, Switzerland
| | - Gerald Schwank
- Department of Biology, Institute for Molecular Health Sciences, ETH Zurich, Zurich, Switzerland
| | - Cary O. Harding
- Department of Molecular and Medical Genetics, School of Medicine, Oregon Science and Health University, Portland, Oregon
| | - Beat Thöny
- Division of Metabolism, University Children's Hospital Zurich and Children's Research Centre, Zurich, Switzerland
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20
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Azabdaftari A, van der Giet M, Schuchardt M, Hennermann JB, Plöckinger U, Querfeld U. The cardiovascular phenotype of adult patients with phenylketonuria. Orphanet J Rare Dis 2019; 14:213. [PMID: 31492166 PMCID: PMC6731621 DOI: 10.1186/s13023-019-1188-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 08/30/2019] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Patients with Phenylketonuria (PKU) are exposed to multiple cardiovascular risk factors, but the clinical significance of these abnormalities is yet unknown. The purpose of this study was to characterize the cardiovascular phenotype in adult patients with PKU by clinical and dietary data, measurements of biochemical markers, and non-invasive examination of vascular functions. RESULTS Twenty-three adult patients with PKU (age: 18-47 y; 30.8 ± 8.4 y) and 28 healthy controls (age: 18-47 y; 30.1 ± 9.1 y) were included in this study. PKU patients had significantly higher systolic and diastolic blood pressure, increased resting heart rate and a higher body mass index. Total cholesterol and non-HDL cholesterol levels were significantly increased in PKU patients, whereas plasma levels of HDL cholesterol and its subfraction HDL2 (but not HDL3) were significantly decreased. The inflammatory markers C-reactive protein and serum amyloid A protein and the serum oxidative stress marker malondialdehyde were significantly higher in patients with PKU. Venous occlusion plethysmography showed marked reduction in post-ischemic blood flow and the carotid to femoral pulse wave velocity was significantly increased demonstrating endothelial dysfunction and increased vascular stiffness. CONCLUSIONS This study shows that the cardiovascular phenotype of adult PKU patients is characterized by an accumulation of traditional cardiovascular risk factors, high levels of inflammatory and oxidative stress markers, endothelial dysfunction and vascular stiffness. These data indicate the need for early cardiovascular risk reduction in patients with PKU.
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Affiliation(s)
- Aline Azabdaftari
- Department of Pediatrics, Division of Gastroenterology, Nephrology and Metabolic Diseases, Charité - Universitätsmedizin Berlin, Campus Virchow-Klinikum, Augstenburger Platz 1, 13353, Berlin, Germany
| | - Markus van der Giet
- Department of Nephrology, Charité - Universitätsmedizin Berlin, Campus Benjamin Franklin, Hindenburgdamm 30, 12203, Berlin, Germany
| | - Mirjam Schuchardt
- Department of Nephrology, Charité - Universitätsmedizin Berlin, Campus Benjamin Franklin, Hindenburgdamm 30, 12203, Berlin, Germany
| | - Julia B Hennermann
- Villa Metabolica, Department of Pediatric and Adolescent Medicine, University Medical Center Mainz, Langenbeckstr, 1, 55131, Mainz, Germany
| | - Ursula Plöckinger
- Interdisciplinary Center of Metabolism: Endocrinology, Diabetes and Metabolism, Charité - Universitätsmedizin Berlin, Campus Virchow-Klinikum, Augustenburger Platz 1, 13353, Berlin, Germany
| | - Uwe Querfeld
- Department of Pediatrics, Division of Gastroenterology, Nephrology and Metabolic Diseases, Charité - Universitätsmedizin Berlin, Campus Virchow-Klinikum, Augstenburger Platz 1, 13353, Berlin, Germany.
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21
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Pecimonova M, Kluckova D, Csicsay F, Reblova K, Krahulec J, Procházkova D, Skultety L, Kadasi L, Soltysova A. Structural and Functional Impact of Seven Missense Variants of Phenylalanine Hydroxylase. Genes (Basel) 2019; 10:E459. [PMID: 31208052 PMCID: PMC6628251 DOI: 10.3390/genes10060459] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Revised: 06/12/2019] [Accepted: 06/13/2019] [Indexed: 11/17/2022] Open
Abstract
The molecular genetics of well-characterized inherited diseases, such as phenylketonuria (PKU) and hyperphenylalaninemia (HPA) predominantly caused by mutations in the phenylalanine hydroxylase (PAH) gene, is often complicated by the identification of many novel variants, often with no obvious impact on the associated disorder. To date, more than 1100 PAH variants have been identified of which a substantial portion have unknown clinical significance. In this work, we study the functionality of seven yet uncharacterized PAH missense variants p.Asn167Tyr, p.Thr200Asn, p.Asp229Gly, p.Gly239Ala, p.Phe263Ser, p.Ala342Pro, and p.Ile406Met first identified in the Czech PKU/HPA patients. From all tested variants, three of them, namely p.Asn167Tyr, p.Thr200Asn, and p.Ile406Met, exerted residual enzymatic activity in vitro similar to wild type (WT) PAH, however, when expressed in HepG2 cells, their protein level reached a maximum of 72.1% ± 4.9%, 11.2% ± 4.2%, and 36.6% ± 7.3% compared to WT PAH, respectively. Remaining variants were null with no enzyme activity and decreased protein levels in HepG2 cells. The chaperone-like effect of applied BH4 precursor increased protein level significantly for p.Asn167Tyr, p.Asp229Gly, p.Ala342Pro, and p.Ile406Met. Taken together, our results of functional characterization in combination with in silico prediction suggest that while p.Asn167Tyr, p.Thr200Asn, and p.Ile406Met PAH variants have a mild impact on the protein, p.Asp229Gly, p.Gly239Ala, p.Phe263Ser, and p.Ala342Pro severely affect protein structure and function.
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Affiliation(s)
- Martina Pecimonova
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, Ilkovicova 6, 842 15 Bratislava, Slovakia.
| | - Daniela Kluckova
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, Ilkovicova 6, 842 15 Bratislava, Slovakia.
| | - Frantisek Csicsay
- Insitute of Virology, Biomedical Research Center, Slovak Academy of Sciences, Dubravska cesta 9, 845 05 Bratislava, Slovakia.
| | - Kamila Reblova
- Central European Institute of Technology, Masaryk University, 625 00 Brno, Czech Republic.
| | - Jan Krahulec
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, Ilkovicova 6, 842 15 Bratislava, Slovakia.
| | - Dagmar Procházkova
- Department of Pediatrics, Medical Faculty of Masaryk University and University Hospital Brno, Černopolní 9, 625 00 Brno, Czech Republic.
| | - Ludovit Skultety
- Insitute of Virology, Biomedical Research Center, Slovak Academy of Sciences, Dubravska cesta 9, 845 05 Bratislava, Slovakia.
| | - Ludevit Kadasi
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, Ilkovicova 6, 842 15 Bratislava, Slovakia.
- Institute for Clinical and Translational Research, Biomedical Research Center, Slovak Academy of Sciences, Dubravska cesta 9, 845 05 Bratislava, Slovakia.
| | - Andrea Soltysova
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, Ilkovicova 6, 842 15 Bratislava, Slovakia.
- Institute for Clinical and Translational Research, Biomedical Research Center, Slovak Academy of Sciences, Dubravska cesta 9, 845 05 Bratislava, Slovakia.
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22
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Kure S, Shintaku H. Tetrahydrobipterin-responsive phenylalanine hydroxylase deficiency. J Hum Genet 2019; 64:67-71. [PMID: 30504912 DOI: 10.1038/s10038-018-0529-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 10/16/2018] [Accepted: 10/19/2018] [Indexed: 11/08/2022]
Affiliation(s)
- Shigeo Kure
- Department of Pediatrics, Tohoku University Graduate School of Medicine, Sendai, Japan.
| | - Haruo Shintaku
- Department of Pediatrics, Osaka City University Graduate School of Medicine, Osaka, Japan
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Dobrowolski SF, Tourkova IL, Robinson LJ, Secunda C, Spridik K, Blair HC. A bone mineralization defect in the Pah enu2 model of classical phenylketonuria involves compromised mesenchymal stem cell differentiation. Mol Genet Metab 2018; 125:193-199. [PMID: 30201326 PMCID: PMC6542264 DOI: 10.1016/j.ymgme.2018.08.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 08/20/2018] [Accepted: 08/20/2018] [Indexed: 11/29/2022]
Abstract
Osteopenia is observed in some patients affected by phenylalanine hydroxylase (PAH) deficient phenylketonuria (PKU). Bone density studies, in diverse PKU patient cohorts, have demonstrated bone disease is neither fully penetrant nor uniform in bone density loss. Biochemical assessment has generated a muddled perspective regarding mechanisms of the PKU bone phenotype where the participation of hyperphenylalaninemia remains unresolved. Osteopenia is realized in the Pahenu2 mouse model of classical PKU; although, characterization is incomplete. We characterized the Pahenu2 bone phenotype and assessed the effect of hyperphenylalaninemia on bone differentiation. Employing Pahenu2 and control animals, cytology, static and dynamic histomorphometry, and biochemistry were applied to further characterize the bone phenotype. These investigations demonstrate Pahenu2 bone density is decreased 33% relative to C57BL/6; bone volume/total volume was similarly decreased; trabecular thickness was unchanged while increased trabecular spacing was observed. Dynamic histomorphometry demonstrated a 25% decrease in mineral apposition. Biochemically, control and PKU animals have similar plasma cortisol, adrenocorticotropic hormone, and 25-hydroxyvitamin D. PKU animals show moderately increased plasma parathyroid hormone while plasma calcium and phosphate are reduced. These data are consistent with a mineralization defect. The effect of hyperphenylalaninemia on bone maturation was assessed in vitro employing bone-derived mesenchymal stem cells (MSCs) and their differentiation into bone. Using standard culture conditions, PAH deficient MSCs differentiate into bone as assessed by in situ alkaline phosphatase activity and mineral staining. However, PAH deficient MSCs cultured in 1200 μM PHE (metric defining classical PKU) show significantly reduced mineralization. These data are the first biological evidence demonstrating a negative impact of hyperphenylalaninemia upon bone maturation. In PAH deficient MSCs, expression of Col1A1 and Rankl are suppressed by hyperphenylalaninemia consistent with reduced bone formation and bone turnover. Osteopenia is intrinsic to PKU pathology in untreated Pahenu2 animals and our data suggests PHE toxicity participates by inhibiting mineralization in the course of MSC bone differentiation.
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Affiliation(s)
- Steven F Dobrowolski
- Department of Pathology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States.
| | - Irina L Tourkova
- Department of Pathology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Lisa J Robinson
- Department of Pathology, Ruby Memorial Hospital, West Virginia University, Morgantown, WV, United States
| | - Cassandra Secunda
- Department of Pathology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Kayla Spridik
- Department of Pathology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Harry C Blair
- Department of Pathology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States; Veteran's Affairs Medical Center, Pittsburgh, PA, United States
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Zori R, Thomas JA, Shur N, Rizzo WB, Decker C, Rosen O, Li M, Schweighardt B, Larimore K, Longo N. Induction, titration, and maintenance dosing regimen in a phase 2 study of pegvaliase for control of blood phenylalanine in adults with phenylketonuria. Mol Genet Metab 2018; 125:217-227. [PMID: 30146451 DOI: 10.1016/j.ymgme.2018.06.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Revised: 05/30/2018] [Accepted: 06/20/2018] [Indexed: 11/21/2022]
Abstract
BACKGROUND Phenylketonuria (PKU) is caused by a deficiency in phenylalanine hydroxylase enzyme activity that leads to phenylalanine (Phe) accumulation in the blood and brain. Elevated blood Phe levels are associated with complications in adults, including neurological, psychiatric, and cognitive issues. Even with nutrition and pharmacological management, the majority of adults with PKU do not maintain blood Phe levels at or below guideline recommended levels. Pegvaliase, PEGylated recombinant Anabaena variabilis phenylalanine ammonia lyase (PAL), converts Phe to trans-cinnamic acid and ammonia, and is an investigational enzyme substitution therapy to lower blood Phe in adults with PKU. METHODS Pegvaliase was administered using an induction, titration, and maintenance dosing regimen in adults with PKU naïve to pegvaliase treatment. Doses were gradually increased until blood Phe ≤ 600 μmol/L was achieved. The maintenance dose was the dose at which participants achieved and sustained blood Phe ≤ 600 μmol/L for at least 4 weeks without dose modification. Analyses were performed for participants who achieved (Group A, n = 11) and did not achieve (Group B, n = 13) maintenance dose during the first 24 weeks of study treatment. RESULTS Baseline mean blood Phe for Group A and Group B were 1135 μmol/L and 1198 μmol/L, respectively. Mean blood Phe ≤ 600 μmol/L was achieved for Group A by Week 11 (mean blood Phe of 508 ± 483 μmol/L) and for Group B by Week 48 (mean blood Phe of 557 ± 389 μmol/L). The most common adverse events involved hypersensitivity reactions, which were mostly mild to moderate in severity and decreased over time. One participant in Group B had four acute systemic hypersensitivity events of anaphylaxis consistent with clinical National Institute of Allergy and Infectious Disease/Food Allergy and Anaphylaxis Network criteria; all events were non-IgE mediated and resolved without sequelae, with pegvaliase dosing discontinued after the fourth event. The incidence and titers of anti-drug antibodies were generally lower in Group A compared to Group B. CONCLUSIONS Pegvaliase administered with an induction, titration, and maintenance dosing regimen demonstrated substantial efficacy at reducing blood Phe in both Group A and Group B by Week 48, with a manageable safety profile in most participants. Blood Phe reduction due to pegvaliase appears to be related to dose, treatment duration, and individual immune response; given additional time on treatment and dose titration, later Phe responders (Group B) achieved benefit similar to early Phe responders (Group A), with similar long-term safety profiles.
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Affiliation(s)
- Roberto Zori
- Department of Pediatrics in the College of Medicine, University of Florida, Gainesville, FL, USA.
| | - Janet A Thomas
- Clinical Genetics and Metabolism, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Natasha Shur
- Pediatrics Genetics Group, Albany Medical Center, Albany, NY, USA
| | - William B Rizzo
- Department of Pediatrics, University of Nebraska Medical Center, Omaha, NE, USA
| | | | - Orli Rosen
- BioMarin Pharmaceutical Inc., Novato, CA, USA
| | - Mingjin Li
- BioMarin Pharmaceutical Inc., Novato, CA, USA
| | | | | | - Nicola Longo
- Division of Medical Genetics, University of Utah, Salt Lake City, UT, USA
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25
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González MJ, Polo MR, Ripollés P, Gassió R, Ormazabal A, Sierra C, Roura RC, Artuch R, Campistol J. White matter microstructural damage in early treated phenylketonuric patients. Orphanet J Rare Dis 2018; 13:188. [PMID: 30367646 PMCID: PMC6203973 DOI: 10.1186/s13023-018-0912-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 09/12/2018] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Despite dietary intervention, individuals with early treated phenylketonuria (ETPKU) could present neurocognitive deficits and white matter (WM) abnormalities. The aim of the present study was to evaluate the microstructural integrity of WM pathways across the whole brain in a cohort of paediatric ETPKU patients compared with healthy controls (HCs), by collecting DTI-MRI (diffusion tensor magnetic resonance imaging) data and diffusion values (mean diffusivity (MD), radial diffusivity (RD) and fractional anisotropy (FA)). METHODS DTI-MRI data and diffusion values (MD, RD, FA) from WM tracts across the whole brain were analized using Tract Based Spatial Statistics (TBSS), in 15 paediatrics TPKU patients (median age: 12 years) and compared with 11 HCs. Areas showing abnormal values in the patient group were correlated (Pearson) with age, lifetime Phe values, last year median and mean Phe, concurrent Phe values in plasma, urine neurotransmitters status biomarkers, and with a processing speed task. RESULTS ETPKU showed bilaterally decreased MD values compared with HCs in the body and splenium of the corpus callosum, superior longitudinal fasciculus, corona radiata and in the posterior limb of the internal capsule. RD values followed a similar pattern, although decreased RD values in PKU patients were also found in the anterior limb of the internal capsule and in the cerebral peduncle. Decreased MD and RD values within the aforementioned regions had significant negative correlations with age, last year median and mean Phe and concurrent Phe values. No correlations were found with monoamines in urine or processing speed task. CONCLUSIONS ETPKU patients showed MD and RD values significantly decreased across the whole brain when compared with HCs, and this damage was associated with high Phe values and the age of patients. Despite this microstructural damage, no affectation in processing speed was observed in patients with good metabolic control. DTI-MRI sequences could be used as a technique to quantify WM damage that is difficult to be detect in T1 or T2-weighted images, but also to quantify damage of WM through the follow up of patients with poor metabolic control in prospective studies.
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Affiliation(s)
- María Julieta González
- Neuropediatric Department, PKU Follow Up Unit, Hospital Sant Joan de Déu (HSJD), Institut de Recerca Sant Joan de Deu (IRSJD), Passeig Sant Joan de Deu 2, Postal code, 08950 Barcelona, Spain
| | - Mónica Rebollo Polo
- Neuroimaging Section, HSJD, IRSJD, Passeig Sant Joan de Deu 2, Postal code, 08950 Barcelona, Spain
| | - Pablo Ripollés
- Neuroimaging Section, HSJD, IRSJD, Passeig Sant Joan de Deu 2, Postal code, 08950 Barcelona, Spain
- Department of Psychology, New York University, 6 Washington Place, 10003 New York, USA
| | - Rosa Gassió
- Neuropediatric Department, PKU Follow Up Unit, Hospital Sant Joan de Déu (HSJD), Institut de Recerca Sant Joan de Deu (IRSJD), Passeig Sant Joan de Deu 2, Postal code, 08950 Barcelona, Spain
| | - Aída Ormazabal
- Clinical Biochemistry Department, HSJD, IRSJD, UB, (CIBERER-ISCIII), Passeig Sant Joan de Deu 2, 08950 Barcelona, Spain
| | - Cristina Sierra
- Clinical Biochemistry Department, HSJD, IRSJD, UB, (CIBERER-ISCIII), Passeig Sant Joan de Deu 2, 08950 Barcelona, Spain
| | - Roser Colomé Roura
- Neuropediatric Department, PKU Follow Up Unit, Hospital Sant Joan de Déu (HSJD), Institut de Recerca Sant Joan de Deu (IRSJD), Passeig Sant Joan de Deu 2, Postal code, 08950 Barcelona, Spain
| | - Rafael Artuch
- Clinical Biochemistry Department, HSJD, IRSJD, UB, (CIBERER-ISCIII), Passeig Sant Joan de Deu 2, 08950 Barcelona, Spain
| | - Jaume Campistol
- Neuropediatric Department, PKU Follow Up Unit, Hospital Sant Joan de Déu (HSJD), Institut de Recerca Sant Joan de Deu (IRSJD), Passeig Sant Joan de Deu 2, Postal code, 08950 Barcelona, Spain
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26
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Himmelreich N, Shen N, Okun JG, Thiel C, Hoffmann GF, Blau N. Relationship between genotype, phenylalanine hydroxylase expression and in vitro activity and metabolic phenotype in phenylketonuria. Mol Genet Metab 2018; 125:86-95. [PMID: 30037505 DOI: 10.1016/j.ymgme.2018.06.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 06/21/2018] [Accepted: 06/22/2018] [Indexed: 01/22/2023]
Abstract
Residual phenylalanine hydroxylase (PAH) activity is the main determinant of the metabolic phenotype in phenylketonuria (PKU). The genotypic heterogeneity of PKU, involving >1000 PAH variants and over 2500 different genotypes, makes genotype-based phenotype prediction challenging. While a relationship between PAH variants and the metabolic phenotype is well established, we questioned the importance of PAH expression and residual in vitro activity for the metabolic phenotype. Thirty-four PAH variants (p.F39 L, p.A47V, p.D59Y, p.I65S, p.R68G, p.R68S, p.E76G, p.A104D, p.D143G, p.R155H, p.R176L, p.V190A, p.G218 V, p.R241C, p.R243Q, p.P244L, p.R252W, p.R261Q, p.E280K, p.R297H, p.A300S, p.I306V, p.A309V, p.L311P, p.A313T, p.L348 V, p.V388 M, A403V, p.R408Q, p.R408W, p.R413P, p.D415N, p.Y417H, and p.A434D) were transiently transfected into COS-7 cells, and expression of PAH was investigated. Expression patterns were compared with in vitro PAH activity and allelic phenotype values (APVs). In vitro PAH activity was significantly higher (p < .01) in variants associated with mild hyperphenylalaninemia (PAH activity = 52.1 ± 8.5%; APV = 6.7-10.0) than that in classic PKU variants (PAH activity = 21.1 ± 7.0%; APV = 0-2.7). Mild PKU variants (PAH activity = 40.2 ± 7.6%; APV = 2.8-6.6) were not significantly different from mild hyperphenylalaninemia, but there was a difference (p < .048) compared with classic PKU phenotypes.
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Affiliation(s)
- Nastassja Himmelreich
- Center for Child and Adolescent Medicine, and Dietmar-Hopp Metabolic Center, University of Heidelberg, Heidelberg, Germany
| | - Nan Shen
- Center for Child and Adolescent Medicine, and Dietmar-Hopp Metabolic Center, University of Heidelberg, Heidelberg, Germany; Department of Rehabilitation Medicine, Xin Hua Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jürgen G Okun
- Center for Child and Adolescent Medicine, and Dietmar-Hopp Metabolic Center, University of Heidelberg, Heidelberg, Germany
| | - Christian Thiel
- Center for Child and Adolescent Medicine, and Dietmar-Hopp Metabolic Center, University of Heidelberg, Heidelberg, Germany
| | - Georg F Hoffmann
- Center for Child and Adolescent Medicine, and Dietmar-Hopp Metabolic Center, University of Heidelberg, Heidelberg, Germany
| | - Nenad Blau
- Center for Child and Adolescent Medicine, and Dietmar-Hopp Metabolic Center, University of Heidelberg, Heidelberg, Germany.
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Huijbregts SCJ, Bosch AM, Simons QA, Jahja R, Brouwers MCGJ, De Sonneville LMJ, De Vries MC, Hofstede FC, Hollak CEM, Janssen MCH, Langendonk JG, Rubio-Gozalbo ME, Van der Meere JJ, Van der Ploeg AT, Van Spronsen FJ. The impact of metabolic control and tetrahydrobiopterin treatment on health related quality of life of patients with early-treated phenylketonuria: A PKU-COBESO study. Mol Genet Metab 2018; 125:96-103. [PMID: 30007854 DOI: 10.1016/j.ymgme.2018.07.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 07/05/2018] [Accepted: 07/06/2018] [Indexed: 11/20/2022]
Abstract
The aim of this study was to examine Health-Related Quality of Life (HRQoL) of patients with Phenylketonuria (PKU) in three different age groups and to investigate the impact of metabolic control and tetrahydrobiopterin (BH4) treatment on HRQoL of these patients. Participants were 90 early-treated patients aged 7 to 40 years (M = 21.0, SD = 10.1) and 109 controls aged 7 to 40.8 years (M = 19.4, SD = 8.6). HRQoL was assessed with the (generic) TNO-AZL questionnaires. Overall, good HRQoL was reported for children below 12 years of age, although they were judged to be less autonomic than their healthy counterparts. Adolescents aged 12-15 years showed poorer HRQoL in the domain "cognitive functioning" compared to controls. For adults ≥16 years, poorer age-controlled HRQoL was found for the domains cognition, depressive moods, and anger, with a further trend for the domain "pain". With respect to metabolic control, only for adult PKU-patients robust associations were observed, indicating poorer functioning, most notably in the domains cognition, sleep, pain, sexuality and anger, with higher historical and concurrent Phe-levels. With respect to BH4-use, effects on HRQoL were again only observed for adult PKU-patients. After controlling for age and historical Phe-levels, small but significant differences in favor of adult BH4-users compared to non-users were observed for HRQoL-categories happiness, anger, and social functioning. Together, these results show that, particularly for adult PKU-patients, HRQoL-problems are evident and that many of these problems are related to (history of) metabolic control. Beneficial effects of BH4-use appear to be limited to those associated with relief from the practical burdens related to the strict dietary treatment regimen, i.e. general mood and sociability, whereas metabolic control is more strongly related to basic physical and cognitive functioning.
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Affiliation(s)
- Stephan C J Huijbregts
- Department of Clinical Child and Adolescent Studies, Leiden University, Leiden, the Netherlands; Leiden Institute for Brain and Cognition, Leiden University Medical Centre, Leiden, the Netherlands.
| | - Annet M Bosch
- Department of Pediatrics, Emma Children's Hospital, Academic Medical Center, University of Amsterdam, the Netherlands
| | - Quirine A Simons
- Department of Clinical Child and Adolescent Studies, Leiden University, Leiden, the Netherlands
| | - Rianne Jahja
- Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | | | - Leo M J De Sonneville
- Department of Clinical Child and Adolescent Studies, Leiden University, Leiden, the Netherlands
| | - Maaike C De Vries
- Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
| | - Floris C Hofstede
- Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Carla E M Hollak
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Academic Medical Center, Amsterdam, the Netherlands
| | | | | | | | - Jaap J Van der Meere
- Department of Developmental and Clinical Neuropsychology, University of Groningen, Groningen, the Netherlands
| | | | - Francjan J Van Spronsen
- Department of Pediatrics, Emma Children's Hospital, Academic Medical Center, University of Amsterdam, the Netherlands
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28
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Evers RAF, van Wegberg AMJ, van Dam E, de Vries MC, Janssen MCH, van Spronsen FJ. Anthropomorphic measurements and nutritional biomarkers after 5 years of BH 4 treatment in phenylketonuria patients. Mol Genet Metab 2018; 124:238-242. [PMID: 30078395 DOI: 10.1016/j.ymgme.2018.06.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Revised: 06/17/2018] [Accepted: 06/17/2018] [Indexed: 10/28/2022]
Affiliation(s)
- Roeland A F Evers
- University of Groningen, University Medical Center Groningen, Division of Metabolic Diseases, PO box 30.001, 9700 RB Groningen, The Netherlands
| | - Annemiek M J van Wegberg
- University of Groningen, University Medical Center Groningen, Division of Metabolic Diseases, PO box 30.001, 9700 RB Groningen, The Netherlands; Radboud University Medical Center Nijmegen, Department of Gastroenterology and Hepatology-Dietetics, PO box 9101, 6500 HB Nijmegen, The Netherlands
| | - Esther van Dam
- University of Groningen, University Medical Center Groningen, Division of Metabolic Diseases, PO box 30.001, 9700 RB Groningen, The Netherlands
| | - Maaike C de Vries
- Radboud University Medical Center Nijmegen, Department of Pediatrics, PO box 9101, 6500 HB Nijmegen, The Netherlands
| | - Mirian C H Janssen
- Radboud University Medical Center, Department of Internal Medicine, PO box 9101, 6500 HB Nijmegen, The Netherlands
| | - Francjan J van Spronsen
- University of Groningen, University Medical Center Groningen, Division of Metabolic Diseases, PO box 30.001, 9700 RB Groningen, The Netherlands.
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29
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Levy HL, Sarkissian CN, Scriver CR. Phenylalanine ammonia lyase (PAL): From discovery to enzyme substitution therapy for phenylketonuria. Mol Genet Metab 2018; 124:223-229. [PMID: 29941359 DOI: 10.1016/j.ymgme.2018.06.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 06/06/2018] [Accepted: 06/07/2018] [Indexed: 01/17/2023]
Abstract
Phenylketonuria (PKU) is a genetic inborn error in metabolism that impacts many people globally, with profound individual and societal consequences when left untreated. The journey of phenylalanine ammonia lyase (PAL) from plant enzyme to enzyme substitution therapy for PKU is a fascinating story that illustrates the importance of collaboration between basic scientists and industry in the drug development process. The story begins with the curiosity of plant physiologists about the origin of lignin, a polymer involved in maintaining the rigidity of plants. They learned that the critical element in this synthesis was an intermediary enzyme that deaminates phenylalanine to cinnamic acid and ammonia (later called phenylalanine ammonia lyase or PAL). Recognition of this ability to metabolize phenylalanine led to subsequent consideration of PAL as a treatment for PKU. This was initially attempted as enteral therapy with extracted enzyme, but that showed only minimal efficacy. Crucially, further development of PAL as a therapy for PKU required quantities of enzyme that could only be obtained after successfully cloning the gene, expressing the enzyme in vitro and modifying the protein via PEGylation to enable parenteral administration of this non-mammalian enzyme. Ultimately, PEGylated PAL was developed as an enzyme substitution therapy for PKU now approved under the name "Palynziq." The multidisciplinary academic-industrial partnership engaged throughout this process has been key to the successful pursuit of this therapeutic possibility and serves as a model for the development of future innovative therapies.
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Affiliation(s)
- Harvey L Levy
- Division of Genetics and Genomics, Boston Children's Hospital, 1 Autumn St., Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA.
| | | | - Charles R Scriver
- Department of Human Genetics, McGill University, Montreal, Quebec H3A 0C7, Canada.
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30
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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] [What about the content of this article? (0)] [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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31
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CHEN T, ZHAO Z, JIANG P, SHU Q. [Research progress on phenotype and genotype of hyperphenylalaninemia]. Zhejiang Da Xue Xue Bao Yi Xue Ban 2018; 47:219-226. [PMID: 30226320 PMCID: PMC10393690 DOI: 10.3785/j.issn.1008-9292.2018.06.01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 04/24/2018] [Indexed: 06/08/2023]
Abstract
Hyperphenylalaninemia(HPA), an autosomal recessive disease, is the most common inborn error of amino acid metabolism, caused by the deficiency of phenylalanine hydroxylase(PAH) or tetrahydrobiopterin(BH4) which induced by mutations of genes. The accumulation of the clinical database and genetic information will enhance the development of novel personalized medicine and to provide more accurate and timely diagnostic and therapeutic approaches for HPA. This paper summarizes the correlations between HPA metabolism and PAH, BH4, pathogenic genes and their distributions in HPA, as well as the phenotypes and genotypes of HPA, so as to provide reference for personalized medicine for HPA.
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Affiliation(s)
| | | | | | - Qiang SHU
- 舒强(1965-), 男, 博士, 主任医师, 教授, 博士生导师, 主要从事出生缺陷综合防治研究; E-mail:
;
https://orcid.org/0000-0002-4106-6255
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32
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Eichinger A, Danecka MK, Möglich T, Borsch J, Woidy M, Büttner L, Muntau AC, Gersting SW. Secondary BH4 deficiency links protein homeostasis to regulation of phenylalanine metabolism. Hum Mol Genet 2018; 27:1732-1742. [PMID: 29514280 DOI: 10.1093/hmg/ddy079] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 02/28/2018] [Indexed: 01/01/2023] Open
Abstract
Metabolic control of phenylalanine concentrations in body fluids is essential for cognitive development and executive function. The hepatic phenylalanine hydroxylating system is regulated by the ratio of l-phenylalanine, which is substrate of phenylalanine hydroxylase (PAH), to the PAH cofactor tetrahydrobiopterin (BH4). Physiologically, phenylalanine availability is governed by nutrient intake, whereas liver BH4 is kept at constant level. In phenylketonuria, PAH deficiency leads to elevated blood phenylalanine and is often caused by PAH protein misfolding with loss of function. Here, we report secondary hepatic BH4 deficiency in Pah-deficient mice. Alterations in de novo synthesis and turnover of BH4 were ruled out as molecular causes. We demonstrate that kinetically instable and aggregation-prone variant Pah proteins trap BH4, shifting the pool of free BH4 towards bound BH4. Interference of PAH protein misfolding with metabolite-based control of l-phenylalanine turnover suggests a mechanistic link between perturbation of protein homeostasis and disturbed regulation of metabolic pathways.
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Affiliation(s)
- Anna Eichinger
- Molecular Pediatrics, Dr von Hauner Children's Hospital, Ludwig-Maximilians-Universität, Munich, Germany
| | | | - Tamara Möglich
- Molecular Pediatrics, Dr von Hauner Children's Hospital, Ludwig-Maximilians-Universität, Munich, Germany
| | - Julia Borsch
- Molecular Pediatrics, Dr von Hauner Children's Hospital, Ludwig-Maximilians-Universität, Munich, Germany
| | - Mathias Woidy
- University Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Lars Büttner
- Molecular Pediatrics, Dr von Hauner Children's Hospital, Ludwig-Maximilians-Universität, Munich, Germany
| | - Ania C Muntau
- University Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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33
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Abstract
Phenylketonuria (PKU) is an autosomal recessive disorder caused by the deficiency of phenylalanine hydroxylase enzyme that catalyzes the conversion of L-phenylalanine to L-tyrosine using tetrahydrobiopterin (BH4) as a cofactor. Among aminoacidopathies, PKU is one of the most prevalent disorders in different populations. It may be caused by deficiency of BH4 or mutations in PAH. About 98% of PKU patients have mutations in the PAH, while the remaining have BH4 deficiency. If PKU is diagnosed earlier in life using advance analytical techniques (e.g., high performance liquid chromatography, mass spectrometry, and polymerase chain reaction), then it is potentially treatable by special diets (L-phenylalanine-free medical formula). However, some complications such as vitamin B12 deficiency, cardiovascular problems, and neurodevelopmental problems have been reported in PKU patients when they ate special diets for a long period. Hence, special diet alone is not a good option for proper treatment. Next generation therapies require structure-function based development. For therapies which target PAH gene (e.g., gene therapy, RNAi, gene editing), a lot of research has yet to be done. Treatment with BH4 therapy is safe and effective but only in BH4-responsive PKU patients. Therefore, research efforts should be focused on the development of more targeted pharmacological and genetic therapies especially PAH gene therapy, which can reduce the burden or deleterious effects of this disease in affected patients.
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Affiliation(s)
- Muhammad Wasim
- Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Jhang Road, P.O. Box 577, Faisalabad, Pakistan; Pakistan Institute of Engineering and Applied Sciences (PIEAS), Nilore, Islamabad, Pakistan
| | - Fazli Rabbi Awan
- Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Jhang Road, P.O. Box 577, Faisalabad, Pakistan; Pakistan Institute of Engineering and Applied Sciences (PIEAS), Nilore, Islamabad, Pakistan
| | - Haq Nawaz Khan
- Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Jhang Road, P.O. Box 577, Faisalabad, Pakistan; Pakistan Institute of Engineering and Applied Sciences (PIEAS), Nilore, Islamabad, Pakistan
| | - Hina Ayesha
- Department of Pediatrics, DHQ Hospital, Faisalabad Medical University, Faisalabad, Pakistan
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34
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Blau N, Martinez A, Hoffmann GF, Thöny B. DNAJC12 deficiency: A new strategy in the diagnosis of hyperphenylalaninemias. Mol Genet Metab 2018; 123:1-5. [PMID: 29174366 DOI: 10.1016/j.ymgme.2017.11.005] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 11/16/2017] [Accepted: 11/16/2017] [Indexed: 01/17/2023]
Abstract
Patients with hyperphenylalaninemia (HPA) are detected through newborn screening for phenylketonuria (PKU). HPA is known to be caused by deficiencies of the enzyme phenylalanine hydroxylase (PAH) or its cofactor tetrahydrobiopterin (BH4). Current guidelines for the differential diagnosis of HPA would, however, miss a recently described DNAJC12 deficiency. The co-chaperone DNAJC12 is, together with the 70kDa heat shock protein (HSP70), responsible for the proper folding of PAH. All DNAJC12-deficient patients investigated to date responded to a challenge with BH4 by lowering their blood phenylalanine levels. In addition, the patients presented with low levels of biogenic amine in CSF and responded to supplementation with BH4, L-dopa/carbidopa and 5-hydroxytryptophan. The phenotypic spectrum ranged from mild autistic features or hyperactivity to severe intellectual disability, dystonia and parkinsonism. Late diagnosis result in permanent neurological disability, while early diagnosed and treated patients develop normally. Molecular diagnostics for DNAJC12 variants are thus mandatory in all patients in which deficiencies of PAH and BH4 are genetically excluded.
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Affiliation(s)
- Nenad Blau
- Dietmar-Hopp-Metabolic Center, University Children's Hospital, Heidelberg, Germany.
| | - Aurora Martinez
- Department of Biomedicine and K.G. Jebsen Centre for Neuropsychiatric Disorders, University of Bergen, Bergen, Norway
| | - Georg F Hoffmann
- Dietmar-Hopp-Metabolic Center, University Children's Hospital, Heidelberg, Germany
| | - Beat Thöny
- Division of Metabolism, University Children's Hospital Zürich, Zürich, Switzerland
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35
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Winn SR, Scherer T, Thöny B, Ying M, Martinez A, Weber S, Raber J, Harding CO. Blood phenylalanine reduction corrects CNS dopamine and serotonin deficiencies and partially improves behavioral performance in adult phenylketonuric mice. Mol Genet Metab 2018; 123:6-20. [PMID: 29331172 PMCID: PMC5786171 DOI: 10.1016/j.ymgme.2017.10.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 10/17/2017] [Accepted: 10/17/2017] [Indexed: 01/12/2023]
Abstract
Central nervous system (CNS) deficiencies of the monoamine neurotransmitters dopamine and serotonin have been implicated in the pathophysiology of neuropsychiatric dysfunction in human phenylketonuria (PKU). In this study, we confirmed the occurrence of brain dopamine and serotonin deficiencies in association with severe behavioral alterations and cognitive impairments in hyperphenylalaninemic C57BL/6-Pahenu2/enu2 mice, a model of human PKU. Phenylalanine-reducing treatments, including either dietary phenylalanine restriction or liver-directed gene therapy, initiated during adulthood were associated with increased brain monoamine content along with improvements in nesting behavior but without a change in the severe cognitive deficits exhibited by these mice. At euthanasia, there was in Pahenu2/enu2 brain a significant reduction in the protein abundance and maximally stimulated activities of tyrosine hydroxylase (TH) and tryptophan hydroxylase 2 (TPH2), the rate limiting enzymes catalyzing neuronal dopamine and serotonin synthesis respectively, in comparison to levels seen in wild type brain. Phenylalanine-reducing treatments initiated during adulthood did not affect brain TH or TPH2 content or maximal activity. Despite this apparent fixed deficit in striatal TH and TPH2 activities, initiation of phenylalanine-reducing treatments yielded substantial correction of brain monoamine neurotransmitter content, suggesting that phenylalanine-mediated competitive inhibition of already constitutively reduced TH and TPH2 activities is the primary cause of brain monoamine deficiency in Pahenu2 mouse brain. We propose that CNS monoamine deficiency may be the cause of the partially reversible adverse behavioral effects associated with chronic HPA in Pahenu2 mice, but that phenylalanine-reducing treatments initiated during adulthood are unable to correct the neuropathology and attendant cognitive deficits that develop during juvenile life in late-treated Pahenu2/enu2 mice.
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Affiliation(s)
- Shelley R Winn
- Department of Medical and Molecular Genetics, Oregon Health & Science University, Mailstop L-103, 3181 Sam Jackson Park Rd., Portland, OR 97239, USA
| | - Tanja Scherer
- Department of Pediatrics, University of Zurich, Steinweissstrasse 75, Zurich CH-8032, Switzerland
| | - Beat Thöny
- Department of Pediatrics, University of Zurich, Steinweissstrasse 75, Zurich CH-8032, Switzerland
| | - Ming Ying
- Department of Biomedicine, KG Jebsen Centre for Neuropsychiatric Disorders, University of Bergen, 5009 Bergen, Norway
| | - Aurora Martinez
- Department of Biomedicine, KG Jebsen Centre for Neuropsychiatric Disorders, University of Bergen, 5009 Bergen, Norway
| | - Sydney Weber
- Department of Behavioral Neuroscience, Oregon Health & Science University, 3181 Sam Jackson Park Rd., Portland, OR 97239, USA
| | - Jacob Raber
- Department of Behavioral Neuroscience, Oregon Health & Science University, 3181 Sam Jackson Park Rd., Portland, OR 97239, USA; Department of Neurology, Division of Neuroscience, ONPRC, Oregon Health & Science University, 3181 Sam Jackson Park Rd., Portland, OR 97239, USA; Department of Radiation Medicine, Division of Neuroscience, ONPRC, Oregon Health & Science University, 3181 Sam Jackson Park Rd., Portland, OR 97239, USA
| | - Cary O Harding
- Department of Medical and Molecular Genetics, Oregon Health & Science University, Mailstop L-103, 3181 Sam Jackson Park Rd., Portland, OR 97239, USA.
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36
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Goldfinger M, Zeile WL, Corado CR, O'Neill CA, Tsuruda LS, Laipis PJ, Cooper JD. Partial rescue of neuropathology in the murine model of PKU following administration of recombinant phenylalanine ammonia lyase (pegvaliase). Mol Genet Metab 2017; 122:33-35. [PMID: 28506393 DOI: 10.1016/j.ymgme.2017.04.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 04/27/2017] [Accepted: 04/27/2017] [Indexed: 01/07/2023]
Abstract
Pegylated recombinant phenylalanine ammonia lyase (pegvaliase) is an enzyme substitution therapy being evaluated for the treatment of phenylketonuria (PKU). PKU is characterized by elevated plasma phenylalanine, which is thought to lead to a deficiency in monoamine neurotransmitters and ultimately, neurocognitive dysfunction. A natural history evaluation in a mouse model of PKU demonstrated a profound decrease in tyrosine hydroxylase (TH) immunoreactivity in several brain regions, beginning at 4weeks of age. Following treatment with pegvaliase, the number of TH positive neurons was increased in several brain regions compared to placebo treated ENU2 mice.
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Affiliation(s)
- Marc Goldfinger
- King's College London, Institute of Psychiatry, Psychology & Neuroscience, Maurice Wohl Clinical Neuroscience Institute, 5 Cutcombe Road, London SE5 9RX, UK
| | | | - Carley R Corado
- BioMarin Pharmaceutical, Inc., 105 Digital Drive, Novato, CA 94949, USA
| | - Charles A O'Neill
- BioMarin Pharmaceutical, Inc., 105 Digital Drive, Novato, CA 94949, USA
| | - Laurie S Tsuruda
- BioMarin Pharmaceutical, Inc., 105 Digital Drive, Novato, CA 94949, USA
| | | | - Jonathan D Cooper
- King's College London, Institute of Psychiatry, Psychology & Neuroscience, Maurice Wohl Clinical Neuroscience Institute, 5 Cutcombe Road, London SE5 9RX, UK.
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37
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Bell SM, Wendt DJ, Zhang Y, Taylor TW, Long S, Tsuruda L, Zhao B, Laipis P, Fitzpatrick PA. Formulation and PEGylation optimization of the therapeutic PEGylated phenylalanine ammonia lyase for the treatment of phenylketonuria. PLoS One 2017; 12:e0173269. [PMID: 28282402 PMCID: PMC5345807 DOI: 10.1371/journal.pone.0173269] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 02/11/2017] [Indexed: 01/03/2023] Open
Abstract
Phenylketonuria (PKU) is a genetic metabolic disease in which the decrease or loss of phenylalanine hydroxylase (PAH) activity results in elevated, neurotoxic levels of phenylalanine (Phe). Due to many obstacles, PAH enzyme replacement therapy is not currently an option. Treatment of PKU with an alternative enzyme, phenylalanine ammonia lyase (PAL), was first proposed in the 1970s. However, issues regarding immunogenicity, enzyme production and mode of delivery needed to be overcome. Through the evaluation of PAL enzymes from multiple species, three potential PAL enzymes from yeast and cyanobacteria were chosen for evaluation of their therapeutic potential. The addition of polyethylene glycol (PEG, MW = 20,000), at a particular ratio to modify the protein surface, attenuated immunogenicity in an animal model of PKU. All three PEGylated PAL candidates showed efficacy in a mouse model of PKU (BTBR Pahenu2) upon subcutaneous injection. However, only PEGylated Anabaena variabilis (Av) PAL-treated mice demonstrated sustained low Phe levels with weekly injection and was the only PAL evaluated that maintained full enzymatic activity upon PEGylation. A PEGylated recombinant double mutant version of AvPAL (Cys503Ser/Cys565Ser), rAvPAL-PEG, was selected for drug development based on its positive pharmacodynamic profile and favorable expression titers. PEGylation was shown to be critical for rAvPAL-PEG efficacy as under PEGylated rAvPAL had a lower pharmacodynamic effect. rAvPAL and rAvPAL-PEG had poor stability at 4°C. L-Phe and trans-cinnamate were identified as activity stabilizing excipients. rAvPAL-PEG is currently in Phase 3 clinical trials to assess efficacy in PKU patients.
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Affiliation(s)
- Sean M. Bell
- BioMarin Pharmaceutical, Novato, California, United States of America
- * E-mail:
| | - Dan J. Wendt
- BioMarin Pharmaceutical, Novato, California, United States of America
| | - Yanhong Zhang
- BioMarin Pharmaceutical, Novato, California, United States of America
| | - Timothy W. Taylor
- BioMarin Pharmaceutical, Novato, California, United States of America
| | - Shinong Long
- BioMarin Pharmaceutical, Novato, California, United States of America
| | - Laurie Tsuruda
- BioMarin Pharmaceutical, Novato, California, United States of America
| | - Bin Zhao
- BioMarin Pharmaceutical, Novato, California, United States of America
| | - Phillip Laipis
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida, United States of America
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38
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Abstract
Purpose: Phenylketonuria (PKU) patients were examined by different MR techniques to explain the pathological changes observed in periventricular white brain matter using conventional MR imaging. Material and Methods: Fifteen patients with treated classical PKU were examined by 1H spectroscopy, relaxometry and diffusion imaging on a whole-body 1.5-T MR imager. Results: Known PKU lesions characterized by T2 enhancement in periventricular white matter were observed in all patients. The MR spectra from the lesioned areas showed a significant decrease in choline concentration. The mean ADC of water decreased and tortuosity increased in PKU lesions compared to control data. Conclusion: The results support the following hypothesis: The T2 increase in the PKU lesion reflects a raised concentration of free water molecules (about 15%) that have an increased trajectory between collisions compared to the same region in controls. The increase in water mobility might be explained by changes in extracellular space volume and myelin sheaths, which, presumably, have a different geometry with more hydrophobic sites in PKU patients. The changes result in increased tortuosity and may be confirmed by the loss of anisotropy in PKU lesions.
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Affiliation(s)
- M Dezortová
- MR Unit, Department of Diagnostic and Interventional Radiology, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
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Hinton CF, Homer CJ, Thompson AA, Williams A, Hassell KL, Feuchtbaum L, Berry SA, Comeau AM, Therrell BL, Brower A, Harris KB, Brown C, Monaco J, Ostrander RJ, Zuckerman AE, Kaye C, Dougherty D, Greene C, Green NS. A framework for assessing outcomes from newborn screening: on the road to measuring its promise. Mol Genet Metab 2016; 118:221-9. [PMID: 27268406 PMCID: PMC4970906 DOI: 10.1016/j.ymgme.2016.05.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 05/28/2016] [Indexed: 10/21/2022]
Abstract
UNLABELLED Newborn screening (NBS) is intended to identify congenital conditions prior to the onset of symptoms in order to provide early intervention that leads to improved outcomes. NBS is a public health success, providing reduction in mortality and improved developmental outcomes for screened conditions. However, it is less clear to what extent newborn screening achieves the long-term goals relating to improved health, growth, development and function. We propose a framework for assessing outcomes for the health and well-being of children identified through NBS programs. The framework proposed here, and this manuscript, were approved for publication by the Secretary of Health and Human Services' Advisory Committee on Heritable Disorders in Newborns and Children (ACHDNC). This framework can be applied to each screened condition within the Recommended Uniform Screening Panel (RUSP), recognizing that the data elements and measures will vary by condition. As an example, we applied the framework to sickle cell disease and phenylketonuria (PKU), two diverse conditions with different outcome measures and potential sources of data. Widespread and consistent application of this framework across state NBS and child health systems is envisioned as useful to standardize approaches to assessment of outcomes and for continuous improvement of the NBS and child health systems. SIGNIFICANCE Successful interventions for newborn screening conditions have been a driving force for public health newborn screening for over fifty years. Organizing interventions and outcome measures into a standard framework to systematically assess outcomes has not yet come into practice. This paper presents a customizable outcomes framework for organizing measures for newborn screening condition-specific health outcomes, and an approach to identifying sources and challenges to populating those measures.
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Affiliation(s)
- Cynthia F Hinton
- Centers for Disease Control and Prevention, Atlanta, GA, United States.
| | - Charles J Homer
- Office of the Assistant Secretary for Planning and Evaluation, Washington, DC, United States
| | - Alexis A Thompson
- Department of Pediatrics, Northwestern University, Chicago, IL, United States
| | - Andrea Williams
- Children's Sickle Cell Foundation, Inc., Pittsburgh, PA, United States
| | | | - Lisa Feuchtbaum
- California Department of Public Health, Richmond, CA, United States
| | - Susan A Berry
- Department of Pediatrics, University of Minnesota, United States
| | - Anne Marie Comeau
- New England Newborn Screening Program and Department of Pediatrics, University of Massachusetts Medical School, Boston, MA, United States
| | - Bradford L Therrell
- Department of Pediatrics, University of Texas Health Science Center, San Antonio, TX, United States
| | - Amy Brower
- American College of Medical Genetics and Genomics, Bethesda, MD, United States
| | | | | | - Jana Monaco
- Organic Acidemia Association, Woodbridge, VA, United States
| | - Robert J Ostrander
- Department of Family Medicine, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Alan E Zuckerman
- Department of Pediatrics and Department of Family Medicine, Georgetown University, Washington, DC, United States
| | - Celia Kaye
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, United States
| | - Denise Dougherty
- Agency for Healthcare Research and Quality, Rockville, MD, United States
| | - Carol Greene
- Department of Pediatrics, University of Maryland, Baltimore, MD, United States
| | - Nancy S Green
- Department of Pediatrics, Columbia University, New York, NY, United States
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Preissler T, Bristot IJ, Costa BML, Fernandes EK, Rieger E, Bortoluzzi VT, de Franceschi ID, Dutra-Filho CS, Moreira JCF, Wannmacher CMD. Phenylalanine induces oxidative stress and decreases the viability of rat astrocytes: possible relevance for the pathophysiology of neurodegeneration in phenylketonuria. Metab Brain Dis 2016; 31:529-37. [PMID: 26573865 DOI: 10.1007/s11011-015-9763-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 11/09/2015] [Indexed: 01/05/2023]
Abstract
The aim of this study was to investigate the effects of phenylalanine on oxidative stress and some metabolic parameters in astrocyte cultures from newborn Wistar rats. Astrocytes were cultured under four conditions: control (0.4 mM phenylalanine concentration in the Dulbecco's Modified Eagle Medium (DMEM) solution), Phe addition to achieve 0.5, 1.0 or 1.5 mM final phenylalanine concentrations. After 72 h the astrocytes were separated for the biochemical measurements. Overall measure of mitochondrial function by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and cell viability measured by lactate dehydrogenase (LDH) assays indicated that phenylalanine induced cell damage at the three concentrations tested. The alteration on the various parameters of oxidative stress indicated that phenylalanine was able to induce free radicals production. Therefore, our results strongly suggest that Phe at concentrations usually found in PKU induces oxidative stress and consequently cell death in astrocytes cultures. Considering the importance of the astrocytes for brain function, it is possible that these astrocytes alterations may contribute to the brain damage found in PKU patients.
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Affiliation(s)
- Thales Preissler
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600-Anexo, CEP, Porto Alegre, RS, 90035-003, Brazil
| | - Ivi Juliana Bristot
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600-Anexo, CEP, Porto Alegre, RS, 90035-003, Brazil
| | - Bruna May Lopes Costa
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600-Anexo, CEP, Porto Alegre, RS, 90035-003, Brazil
| | - Elissa Kerli Fernandes
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600-Anexo, CEP, Porto Alegre, RS, 90035-003, Brazil
| | - Elenara Rieger
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600-Anexo, CEP, Porto Alegre, RS, 90035-003, Brazil
| | - Vanessa Trindade Bortoluzzi
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600-Anexo, CEP, Porto Alegre, RS, 90035-003, Brazil
| | - Itiane Diehl de Franceschi
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600-Anexo, CEP, Porto Alegre, RS, 90035-003, Brazil
| | - Carlos Severo Dutra-Filho
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600-Anexo, CEP, Porto Alegre, RS, 90035-003, Brazil
| | - José Claudio Fonseca Moreira
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600-Anexo, CEP, Porto Alegre, RS, 90035-003, Brazil
| | - Clovis Milton Duval Wannmacher
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600-Anexo, CEP, Porto Alegre, RS, 90035-003, Brazil.
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Christ SE, Price MH, Bodner KE, Saville C, Moffitt AJ, Peck D. Morphometric analysis of gray matter integrity in individuals with early-treated phenylketonuria. Mol Genet Metab 2016; 118:3-8. [PMID: 26947918 DOI: 10.1016/j.ymgme.2016.02.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 02/15/2016] [Accepted: 02/15/2016] [Indexed: 11/23/2022]
Abstract
The most widely-reported neurologic finding in individuals with early-treated phenylketonuria (PKU) is abnormality in the white matter of the brain. In contrast, much less is known regarding the impact of PKU on cortical gray matter (GM) structures. Presently, we applied advanced morphometric methods to the analysis of high-resolution structural MRI images from a sample of 19 individuals with early-treated PKU and an age- and gender-matched comparison group of 22 healthy individuals without PKU. Data analysis revealed decreased GM volume in parietal cortex for the PKU group compared with the non-PKU group. A similar trend was observed for occipital GM volume. There was no evidence of group-related differences in frontal or temporal GM volume. Within the PKU group, we also found a significant relationship between blood phenylalanine levels and GM volume for select posterior cortical sub-regions. Taken together with previous research on white matter and gray matter abnormalities in PKU, the present findings point to the posterior cortices as the primary site of neurostructural changes related to early-treated PKU.
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Affiliation(s)
- Shawn E Christ
- Department of Psychological Sciences, University of Missouri, Columbia, MO, United States.
| | - Mason H Price
- Department of Psychological Sciences, University of Missouri, Columbia, MO, United States
| | - Kimberly E Bodner
- Department of Psychological Sciences, University of Missouri, Columbia, MO, United States
| | - Christopher Saville
- Department of Psychological Sciences, University of Missouri, Columbia, MO, United States
| | - Amanda J Moffitt
- Department of Human Development and Family Studies, University of Missouri, Columbia, MO, United States
| | - Dawn Peck
- Department of Child Health, University of Missouri, Columbia, MO, United States
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Mastrangelo M, Chiarotti F, Berillo L, Caputi C, Carducci C, Di Biasi C, Manti F, Nardecchia F, Leuzzi V. The outcome of white matter abnormalities in early treated phenylketonuric patients: A retrospective longitudinal long-term study. Mol Genet Metab 2015; 116:171-7. [PMID: 26283467 DOI: 10.1016/j.ymgme.2015.08.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 08/08/2015] [Indexed: 11/29/2022]
Abstract
BACKGROUND Pathogenesis and clinical consequences of white matter abnormalities on magnetic resonance imaging (MRI) in phenylketonuric (PKU) patients are incompletely known. OBJECTIVE To study white matter alterations progression and outcome and its relationships with phenylalanine levels and intelligence quotient (IQ) in early treated PKU subjects who underwent serial MRIs during a prolonged follow-up. METHODS 47 early treated PKU patients (mean age 25.1 ± 5.6 years; range 12-37 years) have been enrolled when two or more consecutive brain MRIs, a complete biochemical history, and MRI-concurrent blood phenylalanine levels were available. The severity and extension of white matter abnormalities were expressed in a computed score. Consecutive IQ assessments were available in 24 patients. We analyzed intra- and interindividual white matter alterations variations and their relationship with quality of biochemical control and cognitive outcome. RESULTS Early treated PKU patients showed a high rate of white matter alterations with a relevant increase in frequency/severity from the second decade of life onwards. Age and quality of dietary control before or between subsequent examinations showed an independent cumulative effect on white matter alterations outcome. No significant association was found between white matter alterations and cognitive outcome. A remarkable interindividual variability was found and several patients disclosed incongruity between the trajectory of white matter alterations and biochemical control. About 30% of white matter alterations variability remains unexplained by the disease-associated determinants. CONCLUSIONS The evolution of white matter alterations is not significantly affected by intellectual outcome and is affected by aging, chronic exposure to phenylalanine, and unknown individual factors.
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Affiliation(s)
- Mario Mastrangelo
- Department of Paediatrics, Child Neurology and Psychiatry, Sapienza University of Rome.
| | - Flavia Chiarotti
- Section of NeuroToxicology and Neuroendocrinology, Department of Cell Biology and Neuroscience, National Institute of Health, Rome.
| | - Luana Berillo
- Department of Paediatrics, Child Neurology and Psychiatry, Sapienza University of Rome.
| | - Caterina Caputi
- Department of Paediatrics, Child Neurology and Psychiatry, Sapienza University of Rome.
| | - Claudia Carducci
- Department of Experimental Medicine, "Sapienza University of Rome".
| | - Claudio Di Biasi
- Department of Emergency Radiology, "Sapienza University of Rome"
| | - Filippo Manti
- Department of Paediatrics, Child Neurology and Psychiatry, Sapienza University of Rome.
| | - Francesca Nardecchia
- Department of Paediatrics, Child Neurology and Psychiatry, Sapienza University of Rome; Department of Physiology and Pharmacology, "Sapienza University of Rome".
| | - Vincenzo Leuzzi
- Department of Paediatrics, Child Neurology and Psychiatry, Sapienza University of Rome.
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Miao XN, Siu KL, Cai H. Nifedipine attenuation of abdominal aortic aneurysm in hypertensive and non-hypertensive mice: Mechanisms and implications. J Mol Cell Cardiol 2015; 87:152-9. [PMID: 26254182 DOI: 10.1016/j.yjmcc.2015.07.031] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 07/28/2015] [Accepted: 07/30/2015] [Indexed: 02/07/2023]
Abstract
Rupture of abdominal aortic aneurysm (AAA) is a lethal event. No oral medicine has been available to prevent or treat AAA. We have recently identified a novel mechanism of eNOS uncoupling by which AAA develops, in angiotensin II (Ang II) infused hyperphenylalaninemia 1 (hph-1) mice. Using this unique model we investigated effects on AAA formation of the L-type calcium channel blocker nifedipine, in view of the unclear relationship between hypertension and AAA, and unclear mechanisms of aneurysm protective effects of some blood pressure lowering drugs. Six-month old hph-1 mice were infused with Ang II (0.7 mg/kg/day) for 2 weeks, and fed nifedipine chow at two different doses (5 and 20 mg/kg/day). While the high dose of nifedipine reduced blood pressure, the lower dose had no effect. Interestingly, the incidence rate of AAA dropped from 71% to 7 and 12.5% for low and high dose nifedipine, respectively. Expansion of abdominal aorta, determined by ultrasound imaging, was abolished by both doses of nifedipine, which recoupled eNOS completely to improve NO bioavailability. Both also abrogated aortic superoxide production. Of note, Ang II activation of NADPH oxidase in vascular smooth muscle cells and endothelial cells, known to uncouple eNOS, was also attenuated by nifedipine. Although low dose was a sub-pressor while the high dose reduced blood pressure via inhibition of calcium channels, both doses were highly effective in preventing AAA by preserving eNOS coupling activity to eliminate sustained oxidative stress from uncoupled eNOS. These data demonstrate that oral treatment of nifedipine is highly effective in preserving eNOS function to attenuate AAA formation. Nifedipine may be used for AAA prevention either at low dose in AAA risk group, or at high dose in patients with co-existing hypertension.
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Affiliation(s)
- Xiao Niu Miao
- Divisions of Molecular Medicine and Cardiology, Departments of Anesthesiology and Medicine, Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90025, USA; School of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, PR China
| | - Kin Lung Siu
- Divisions of Molecular Medicine and Cardiology, Departments of Anesthesiology and Medicine, Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90025, USA
| | - Hua Cai
- Divisions of Molecular Medicine and Cardiology, Departments of Anesthesiology and Medicine, Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90025, USA.
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Papassin J, Pierunek J, Corne C, Besson G. Phenylketonuria, an unusual diagnosis of mental retardation in an adult patient. Rev Neurol (Paris) 2015; 171:739-40. [PMID: 26184060 DOI: 10.1016/j.neurol.2015.04.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Revised: 04/15/2015] [Accepted: 04/18/2015] [Indexed: 11/18/2022]
Affiliation(s)
- J Papassin
- Service de neurologie générale, CHU de Grenoble, avenue Maquis-du-Grésivaudan, 38700 La Tronche, France.
| | - J Pierunek
- Laboratoire de biochimie génétique et moléculaire, CHU de Grenoble, 38043 Grenoble cedex 09, France
| | - C Corne
- Laboratoire de biochimie génétique et moléculaire, CHU de Grenoble, 38043 Grenoble cedex 09, France
| | - G Besson
- Service de neurologie générale, CHU de Grenoble, avenue Maquis-du-Grésivaudan, 38700 La Tronche, France
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Nardecchia F, Manti F, Chiarotti F, Carducci C, Carducci C, Leuzzi V. Neurocognitive and neuroimaging outcome of early treated young adult PKU patients: A longitudinal study. Mol Genet Metab 2015; 115:84-90. [PMID: 25952249 DOI: 10.1016/j.ymgme.2015.04.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 04/22/2015] [Accepted: 04/25/2015] [Indexed: 10/23/2022]
Abstract
The aim of the study was to explore the outcome of neurocognitive deficits and neuroimaging correlates in young adult early treated phenylketonuric (PKU) patients. We conducted a longitudinal study of 14 PKU patients that were assessed for IQ and neuropsychological functioning including executive functions (EF) over 14 years of follow-up (age range at 1st and 2nd assessments were 7.8-13.5 and 22.2-27.7 years, respectively). The IQ of all 14 PKU patients was within the normal range. With respect to the 1st assessment, mean IQ at follow-up did not decrease significantly. Compared to control subjects (n = 14), mean IQ of patients was significantly lower (p = .0005). Throughout adolescence and early adulthood there was an improvement of neuropsychological functioning of PKU patients in spite of the relaxation of diet, however some deficits were still detectable when compared to controls. All patients that underwent a second MRI scan showed white matter alterations ranging from mild to severe which was correlated neither with IQ nor with EF scoring. Cognitive, neuropsychological and neuroimaging outcome was influenced from life-long and/or second decade of life metabolic control. Nevertheless patients' developmental trajectories were in some cases independent from metabolic control. Our results support the hypothesis of an individual vulnerability to phenylalanine. However, as long as individual factors that account for the vulnerability to Phe are not recognized, strict dietary control is recommended for all the patients also in the second decade of life.
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Affiliation(s)
- Francesca Nardecchia
- Department of Pediatrics and Child and Adolescent Neuropsychiatry, SAPIENZA University of Rome, Via dei Sabelli 108, 00185 Rome, Italy; Department of Physiology and Pharmacology, SAPIENZA University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy.
| | - Filippo Manti
- Department of Pediatrics and Child and Adolescent Neuropsychiatry, SAPIENZA University of Rome, Via dei Sabelli 108, 00185 Rome, Italy.
| | - Flavia Chiarotti
- Istituto Superiore di Sanità, Department of Cell Biology and Neuroscience, Viale Regina Elena 299, 00161 Rome, Italy.
| | - Claudia Carducci
- Department of Experimental Medicine, SAPIENZA University of Rome, Viale del Policlinico 155, 00161 Rome, Italy.
| | - Carla Carducci
- Department of Experimental Medicine, SAPIENZA University of Rome, Viale del Policlinico 155, 00161 Rome, Italy.
| | - Vincenzo Leuzzi
- Department of Pediatrics and Child and Adolescent Neuropsychiatry, SAPIENZA University of Rome, Via dei Sabelli 108, 00185 Rome, Italy.
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Seki M, Takizawa T, Suzuki S, Shimizu T, Shibata H, Ishii T, Hasegawa T, Suzuki N. Adult phenylketonuria presenting with subacute severe neurologic symptoms. J Clin Neurosci 2015; 22:1361-3. [PMID: 25913748 DOI: 10.1016/j.jocn.2015.02.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 01/21/2015] [Accepted: 02/03/2015] [Indexed: 11/18/2022]
Abstract
We report a 48-year-old Japanese woman with phenylketonuria (PKU) who presented with severe neurological symptoms more than 30 years after discontinuation of dietary treatment. She was diagnosed with PKU at 6-years-old and was treated with a phenylalanine restricted diet until she was 15 years old. When she was 48-years-old she started having difficulty walking. After several months, she presented with severe disturbance of consciousness and was admitted. She was diagnosed as having neurological complications associated with PKU. We observed temporal changes in her laboratory data, brain MRI and single-photon emission computed tomography (SPECT) scan findings. Brain MRI on T2-weighted, fluid-attenuated inversion recovery and diffusion-weighted images revealed high intensity lesions in her bilateral frontal lobes and 123I-IMP SPECT showed marked and diffuse hypoperfusion in the bilateral cerebrum and cerebellum. After the resumption of dietary treatment, serum phenylalanine concentrations immediately decreased to the normal range. However, her neurological symptoms took longer to improve. We also found no clear temporal association between MRI findings and clinical severity. SPECT abnormalities showed marked improvement after treatment. It is well known that PKU patients who discontinue the dietary restriction from their childhood develop minor neurological impairments. However, PKU patients with late-onset severe neurological symptoms are very rare. To our knowledge, this is the first report regarding SPECT findings of PKU patients with late-onset severe neurological deterioration.
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Affiliation(s)
- M Seki
- Department of Neurology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.
| | - T Takizawa
- Department of Neurology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - S Suzuki
- Department of Neurology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - T Shimizu
- Department of Neurology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - H Shibata
- Department of Pediatrics, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - T Ishii
- Department of Pediatrics, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - T Hasegawa
- Department of Pediatrics, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - N Suzuki
- Department of Neurology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
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47
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Affiliation(s)
- Beat Thöny
- 1 Division of Metabolism, Department of Pediatrics, University of Zürich , CH-8032 Zürich, Switzerland
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48
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Stojiljkovic M, Klaassen K, Djordjevic M, Sarajlija A, Kecman B, Ugrin M, Zukic B, Desviat LR, Pavlovic S, Perez B. Tetrahydrobiopterin deficiency among Serbian patients presenting with hyperphenylalaninemia. J Pediatr Endocrinol Metab 2015; 28:477-80. [PMID: 25418970 DOI: 10.1515/jpem-2014-0297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 09/29/2014] [Indexed: 11/15/2022]
Abstract
Hyperphenylalaninemia (HPA) [phenylketonuria (PKU) and tetrahydrobiopterin (BH4) deficiencies] is rare inborn metabolic disease characterized by elevated phenylalanine level in body fluids. In Serbia, 62 HPA patients have been identified through newborn screening since 1983. However, pterin pattern analysis is not performed. We present a patient initially diagnosed and treated as classical PKU. At 3 years of age, during infection with H1N1 influenza A virus, the patient first developed a neurologic crisis with encephalopathy and dystonic movements. We suspected that the patient is the first case of BH4 deficiency identified in Serbia. Genetic analyses showed that the patient does not have disease-causing variants of the PAH gene and carries a p.Asp136Val mutation in homozygous state in the PTS gene. For patients with treatable rare diseases, like PKU and BH4 deficiencies, correct diagnosis is crucial for the implementation of optimal treatment. If biochemical tests needed for differential diagnosis are not available, our experience emphasizes the necessity of immediate genetic testing after newborn screening.
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49
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Hood A, Antenor-Dorsey JAV, Rutlin J, Hershey T, Shimony JS, McKinstry RC, Grange DK, Christ SE, Steiner R, White DA. Prolonged exposure to high and variable phenylalanine levels over the lifetime predicts brain white matter integrity in children with phenylketonuria. Mol Genet Metab 2015; 114:19-24. [PMID: 25481106 PMCID: PMC4277899 DOI: 10.1016/j.ymgme.2014.11.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 11/04/2014] [Accepted: 11/06/2014] [Indexed: 10/24/2022]
Abstract
In this study, we retrospectively examined the microstructural white matter integrity of children with early- and continuously-treated PKU (N=36) in relation to multiple indices of phenylalanine (Phe) control over the lifetime. White matter integrity was assessed using mean diffusivity (MD) from diffusion tensor imaging (DTI). Eight lifetime indices of Phe control were computed to reflect average Phe (mean, index of dietary control), variability in Phe (standard deviation, standard error of estimate, % spikes), change in Phe with age (slope), and prolonged exposure to Phe (mean exposure, standard deviation exposure). Of these indices, mean Phe, mean exposure, and standard deviation exposure were the most powerful predictors of widespread microstructural white matter integrity compromise. Findings from the two previously unexamined exposure indices reflected the accumulative effects of elevations and variability in Phe. Given that prolonged exposure to elevated and variable Phe was particularly detrimental to white matter integrity, Phe should be carefully monitored and controlled throughout childhood, without liberalization of Phe control as children with PKU age.
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Affiliation(s)
- Anna Hood
- Department of Psychology, Washington University, Campus Box 1125, St. Louis, MO 63130, USA
| | - Jo Ann V Antenor-Dorsey
- Department of Psychiatry, Washington University School of Medicine, Campus Box 8134, St. Louis, MO 63110, USA
| | - Jerrel Rutlin
- Department of Psychiatry, Washington University School of Medicine, Campus Box 8134, St. Louis, MO 63110, USA
| | - Tamara Hershey
- Department of Psychiatry, Washington University School of Medicine, Campus Box 8134, St. Louis, MO 63110, USA; Mallinckrodt Institute of Radiology, Washington University School of Medicine, Campus Box 8131, St. Louis, MO 63110, USA; Department of Neurology, Washington University School of Medicine, Campus Box 8111, St. Louis, MO 63110, USA
| | - Joshua S Shimony
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, Campus Box 8131, St. Louis, MO 63110, USA
| | - Robert C McKinstry
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, Campus Box 8131, St. Louis, MO 63110, USA; Department of Pediatrics, Washington University School of Medicine, Campus Box 8116, St. Louis, MO 63110, USA
| | - Dorothy K Grange
- Department of Pediatrics, Washington University School of Medicine, Campus Box 8116, St. Louis, MO 63110, USA
| | - Shawn E Christ
- Department of Psychological Sciences, University of Missouri, 210 McAlester Hall, Columbia, MO 65211, USA
| | - Robert Steiner
- Department of Pediatrics, Institute on Development and Disability, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd., Portland, OR, 97239 USA; Department of Molecular & Medical Genetics, Institute on Development and Disability, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd., Portland, OR 97239, USA
| | - Desiree A White
- Department of Psychology, Washington University, Campus Box 1125, St. Louis, MO 63130, USA.
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Lucaccioni L, Schwahn BC, Donaldson M, Giacomozzi C. Central precocious puberty in a 3 year-old girl with Phenylketonuria: a rare association? BMC Endocr Disord 2014; 14:38. [PMID: 24773629 PMCID: PMC4013055 DOI: 10.1186/1472-6823-14-38] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 04/08/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Central precocious puberty (CPP) and phenylketonuria (PKU) are two rare conditions, the latter being the rarer. To date, only one case featuring both these conditions has been reported, and hyperphenylalaninemia was assumed triggering CPP. CASE PRESENTATION We present a 3.2 years old girl referred with a 12 months history of breast and pubic hair development, and vaginal discharge. Hyperphenylalaninemia had been identified by newborn screening and PKU subsequently confirmed by plasma amino acid and genetic analysis. Early dietary control of plasma phenylalanine had been excellent afterwards, resulting in phenylalanine concentrations consistently within the recommended range. Clinical scenario, hormonal assessment and imaging were in keeping with true idiopathic central precocious puberty. Treatment with long lasting gonadotropin-releasing hormone analogue led to regression of secondary sexual characteristics. CONCLUSION We describe for the first time CPP in a girl affected with PKU but with persistently well controlled blood phenylalanine concentrations. This finding is in contrast to a previous report which suggested persistently high phenylalaninemia levels as potential trigger for CPP in PKU patients. Our report, together with the lack of evidence in published cohort studies of children with PKU, strongly suggests this rare association is coincidental and independent of the presence of severe hyperphenylalaninemia.
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Affiliation(s)
- Laura Lucaccioni
- Paediatric Unit, Department of Medical and Surgical Sciences for the Children and Adults, University of Modena & Reggio Emilia, via del Pozzo n. 71, 41125 Modena, Italy
- Paediatric Endocrinology Unit, Royal Hospital for Sick Children, Dalnair St, Yorkhill, G3 8SJ Glasgow, UK
| | - Bernd C Schwahn
- Metabolic Unit, Royal Hospital for Sick Children, Dalnair St, Yorkhill, G3 8SJ Glasgow, UK
| | - Malcolm Donaldson
- Paediatric Endocrinology Unit, Royal Hospital for Sick Children, Dalnair St, Yorkhill, G3 8SJ Glasgow, UK
| | - Claudio Giacomozzi
- Paediatric Endocrinology Unit, Royal Hospital for Sick Children, Dalnair St, Yorkhill, G3 8SJ Glasgow, UK
- Dipartimento di Medicina Pediatrica, Bambino Gesù Children's Hospital, Piazza S. Onofiro 4, 00165 Rome, Italy
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