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The Utility of Genomic Testing for Hyperphenylalaninemia. J Clin Med 2022; 11:jcm11041061. [PMID: 35207333 PMCID: PMC8879487 DOI: 10.3390/jcm11041061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 02/08/2022] [Accepted: 02/16/2022] [Indexed: 12/10/2022] Open
Abstract
Hyperphenylalaninemia (HPA), the most common amino acid metabolism disorder, is caused by defects in enzymes involved in phenylalanine metabolism, with the consequent accumulation of phenylalanine and its secondary metabolites in body fluids and tissues. Clinical manifestations of HPA include mental retardation, and its early diagnosis with timely treatment can improve the prognosis of affected patients. Due to the genetic complexity and heterogeneity of HPA, high-throughput molecular technologies, such as next-generation sequencing (NGS), are becoming indispensable tools to fully characterize the etiology, helping clinicians to promptly identify the exact patients’ genotype and determine the appropriate treatment. In this review, after a brief overview of the key enzymes involved in phenylalanine metabolism, we represent the wide spectrum of genes and their variants associated with HPA and discuss the utility of genomic testing for improved diagnosis and clinical management of HPA.
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102
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Glycomacropeptide in PKU-Does It Live Up to Its Potential? Nutrients 2022; 14:nu14040807. [PMID: 35215457 PMCID: PMC8875363 DOI: 10.3390/nu14040807] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/30/2022] [Accepted: 02/07/2022] [Indexed: 02/01/2023] Open
Abstract
The use of casein glycomacropeptide (CGMP) as a protein substitute in phenylketonuria (PKU) has grown in popularity. CGMP is derived from κ casein and is a sialic-rich glycophosphopeptide, formed by the action of chymosin during the production of cheese. It comprises 20–25% of total protein in whey products and has key biomodulatory properties. In PKU, the amino acid sequence of CGMP has been adapted by adding the amino acids histidine, leucine, methionine, tyrosine and tryptophan naturally low in CGMP. The use of CGMP compared to mono amino acids (L-AAs) as a protein substitute in the treatment of PKU promises several potential clinical benefits, although any advantage is supported only by evidence from non-PKU conditions or PKU animal models. This review examines if there is sufficient evidence to support the bioactive properties of CGMP leading to physiological benefits when compared to L-AAs in PKU, with a focus on blood phenylalanine control and stability, body composition, growth, bone density, breath odour and palatability.
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103
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Krämer J, Kang R, Grimm LM, De Cola L, Picchetti P, Biedermann F. Molecular Probes, Chemosensors, and Nanosensors for Optical Detection of Biorelevant Molecules and Ions in Aqueous Media and Biofluids. Chem Rev 2022; 122:3459-3636. [PMID: 34995461 PMCID: PMC8832467 DOI: 10.1021/acs.chemrev.1c00746] [Citation(s) in RCA: 109] [Impact Index Per Article: 54.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Synthetic molecular probes, chemosensors, and nanosensors used in combination with innovative assay protocols hold great potential for the development of robust, low-cost, and fast-responding sensors that are applicable in biofluids (urine, blood, and saliva). Particularly, the development of sensors for metabolites, neurotransmitters, drugs, and inorganic ions is highly desirable due to a lack of suitable biosensors. In addition, the monitoring and analysis of metabolic and signaling networks in cells and organisms by optical probes and chemosensors is becoming increasingly important in molecular biology and medicine. Thus, new perspectives for personalized diagnostics, theranostics, and biochemical/medical research will be unlocked when standing limitations of artificial binders and receptors are overcome. In this review, we survey synthetic sensing systems that have promising (future) application potential for the detection of small molecules, cations, and anions in aqueous media and biofluids. Special attention was given to sensing systems that provide a readily measurable optical signal through dynamic covalent chemistry, supramolecular host-guest interactions, or nanoparticles featuring plasmonic effects. This review shall also enable the reader to evaluate the current performance of molecular probes, chemosensors, and nanosensors in terms of sensitivity and selectivity with respect to practical requirement, and thereby inspiring new ideas for the development of further advanced systems.
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Affiliation(s)
- Joana Krämer
- Institute
of Nanotechnology, Karlsruhe Institute of
Technology (KIT), Hermann-von-Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Rui Kang
- Institute
of Nanotechnology, Karlsruhe Institute of
Technology (KIT), Hermann-von-Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Laura M. Grimm
- Institute
of Nanotechnology, Karlsruhe Institute of
Technology (KIT), Hermann-von-Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Luisa De Cola
- Institute
of Nanotechnology, Karlsruhe Institute of
Technology (KIT), Hermann-von-Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
- Dipartimento
DISFARM, University of Milano, via Camillo Golgi 19, 20133 Milano, Italy
- Department
of Molecular Biochemistry and Pharmacology, Instituto di Ricerche Farmacologiche Mario Negri, IRCCS, 20156 Milano, Italy
| | - Pierre Picchetti
- Institute
of Nanotechnology, Karlsruhe Institute of
Technology (KIT), Hermann-von-Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
- P.P.: email,
| | - Frank Biedermann
- Institute
of Nanotechnology, Karlsruhe Institute of
Technology (KIT), Hermann-von-Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
- F.B.: email,
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104
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van der Goot E, Vink SN, van Vliet D, van Spronsen FJ, Falcao Salles J, van der Zee EA. Gut-Microbiome Composition in Response to Phenylketonuria Depends on Dietary Phenylalanine in BTBR Pah enu2 Mice. Front Nutr 2022; 8:735366. [PMID: 35059423 PMCID: PMC8763796 DOI: 10.3389/fnut.2021.735366] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 11/17/2021] [Indexed: 01/03/2023] Open
Abstract
Phenylketonuria (PKU) is a metabolic disorder caused by a hepatic enzyme deficiency causing high blood and brain levels of the amino acid Phenylalanine (Phe), leading to severe cognitive and psychological deficits that can be prevented, but not completely, by dietary treatment. The behavioral outcome of PKU could be affected by the gut-microbiome-brain axis, as diet is one of the major drivers of the gut microbiome composition. Gut-microbiome alterations have been reported in treated patients with PKU, although the question remains whether this is due to PKU, the dietary treatment, or their interaction. We, therefore, examined the effects of dietary Phe restriction on gut-microbiome composition and relationships with behavioral outcome in mice. Male and female BTBR Pahenu2 mice received either a control diet (normal protein, “high” Phe), liberalized Phe-restricted (33% natural protein restriction), or severe Phe-restricted (75% natural protein restriction) diet with protein substitutes for 10 weeks (n = 14 per group). Their behavioral performance was examined in an open field test, novel and spatial object location tests, and a balance beam. Fecal samples were collected and sequenced for the bacterial 16S ribosomal RNA (rRNA) region. Results indicated that PKU on a high Phe diet reduced Shannon diversity significantly and altered the microbiome composition compared with wild-type animals. Phe-restriction prevented this loss in Shannon diversity but changed community composition even more than the high-Phe diet, depending on the severity of the restriction. Moreover, on a taxonomic level, we observed the highest number of differentially abundant genera in animals that received 75% Phe-restriction. Based on correlation analyses with differentially abundant taxa, the families Entereococacceae, Erysipelotrichaceae, Porphyromonadaceae, and the genus Alloprevotella showed interesting relationships with either plasma Phe levels and/or object memory. According to our results, these bacterial taxa could be good candidates to start examining the microbial metabolic potential and probiotic properties in the context of PKU. We conclude that PKU leads to an altered gut microbiome composition in mice, which is least severe on a liberalized Phe-restricted diet. This may suggest that the current Phe-restricted diet for PKU patients could be optimized by taking dietary effects on the microbiome into account.
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Affiliation(s)
- Els van der Goot
- Molecular Neurobiology, Groningen Institute for Evolutionary Sciences, University of Groningen, Groningen, Netherlands.,Microbial Ecology Cluster, Groningen Institute for Evolutionary Sciences, University of Groningen, Groningen, Netherlands
| | - Stefanie N Vink
- Microbial Ecology Cluster, Groningen Institute for Evolutionary Sciences, University of Groningen, Groningen, Netherlands
| | - Danique van Vliet
- Department of Pediatrics, Beatrix Children's Hospital, University Medical Center Groningen, Groningen, Netherlands
| | - Francjan J van Spronsen
- Department of Pediatrics, Beatrix Children's Hospital, University Medical Center Groningen, Groningen, Netherlands
| | - Joana Falcao Salles
- Microbial Ecology Cluster, Groningen Institute for Evolutionary Sciences, University of Groningen, Groningen, Netherlands
| | - Eddy A van der Zee
- Molecular Neurobiology, Groningen Institute for Evolutionary Sciences, University of Groningen, Groningen, Netherlands
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105
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Krude H, Berner R, Hoffmann GF. Diagnostik seltener Erkrankungen in der Pädiatrie. Monatsschr Kinderheilkd 2022. [DOI: 10.1007/s00112-021-01354-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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106
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Borges AC, Broersen K, Leandro P, Fernandes TG. Engineering Organoids for in vitro Modeling of Phenylketonuria. Front Mol Neurosci 2022; 14:787242. [PMID: 35082602 PMCID: PMC8784555 DOI: 10.3389/fnmol.2021.787242] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/29/2021] [Indexed: 12/15/2022] Open
Abstract
Phenylketonuria is a recessive genetic disorder of amino-acid metabolism, where impaired phenylalanine hydroxylase function leads to the accumulation of neurotoxic phenylalanine levels in the brain. Severe cognitive and neuronal impairment are observed in untreated/late-diagnosed patients, and even early treated ones are not safe from life-long sequelae. Despite the wealth of knowledge acquired from available disease models, the chronic effect of Phenylketonuria in the brain is still poorly understood and the consequences to the aging brain remain an open question. Thus, there is the need for better predictive models, able to recapitulate specific mechanisms of this disease. Human induced pluripotent stem cells (hiPSCs), with their ability to differentiate and self-organize in multiple tissues, might provide a new exciting in vitro platform to model specific PKU-derived neuronal impairment. In this review, we gather what is known about the impact of phenylalanine in the brain of patients and highlight where hiPSC-derived organoids could contribute to the understanding of this disease.
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Affiliation(s)
- Alice C. Borges
- Department of Bioengineering and iBB – Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
- Associate Laboratory i4HB – Institute for Health and Bioeconomy, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Kerensa Broersen
- Department of Applied Stem Cell Technologies, Faculty of Science and Technology, Technical Medical Centre, University of Twente, Enschede, Netherlands
| | - Paula Leandro
- Faculty of Pharmacy, iMed.ULisboa - Research Institute for Medicines, Universidade de Lisboa, Lisbon, Portugal
| | - Tiago G. Fernandes
- Department of Bioengineering and iBB – Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
- Associate Laboratory i4HB – Institute for Health and Bioeconomy, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
- *Correspondence: Tiago G. Fernandes,
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107
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OUP accepted manuscript. Nutr Rev 2022; 80:2100-2112. [DOI: 10.1093/nutrit/nuac024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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108
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Peng D, Ganye Z, Gege S, Yanjie X, Ning L, Xiangdong K. Clinical application of non-invasive prenatal diagnosis of phenylketonuria based on haplotypes via paired-end molecular tags and weighting algorithm. BMC Med Genomics 2021; 14:294. [PMID: 34920737 PMCID: PMC8684071 DOI: 10.1186/s12920-021-01141-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 12/01/2021] [Indexed: 11/11/2022] Open
Abstract
Background Phenylketonuria (PKU) is a metabolic disease that can cause severe and irreversible brain damage without treatment. Methods Here we developed a non-invasive prenatal diagnosis (NIPD) technique based on haplotypes via paired-end molecular tags and weighting algorithm and applied it to the NIPD of PKU to evaluate its accuracy and feasibility in the early pregnancy. A custom-designed hybridization probes containing regions in phenylalanine hydroxylase (PAH) gene and its 1 Mb flanking region were used for target sequencing on genomic and maternal plasma DNA (7–13 weeks of gestation) to construct the parental haplotypes and the proband’s haplotype. Fetal haplotype was then inferred combined with the parental haplotypes and the proband’s haplotype. The presence of haplotypes linked to both the maternal and paternal mutant alleles indicated affected fetuses. The fetal genotypes were further validated by invasive prenatal diagnosis in a blinded fashion. Results This technique has been successfully applied in twenty-one cases. Six fetuses were diagnosed as patients carrying both of the mutated haplotypes inherited from their parents. Eleven fetuses were carriers of one heterozygous PAH variants, six of which were paternal and five of which were maternal. Four fetuses were absence of pathogenic alleles. All results were consistent with the prenatal diagnosis through amniotic fluid. Conclusions The results showed that our new technique applied to the genotyping of fetuses with high risk for PKU achieves an accurate detection at an early stage of pregnancy with low fetal fraction in cell free DNA. Supplementary Information The online version contains supplementary material available at 10.1186/s12920-021-01141-4.
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Affiliation(s)
- Dai Peng
- The Genetics and Prenatal Diagnosis Center, The Department of Obstetrics and Gynecology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, Henan, China
| | - Zhao Ganye
- The Genetics and Prenatal Diagnosis Center, The Department of Obstetrics and Gynecology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, Henan, China
| | - Sun Gege
- The Genetics and Prenatal Diagnosis Center, The Department of Obstetrics and Gynecology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, Henan, China
| | - Xia Yanjie
- The Genetics and Prenatal Diagnosis Center, The Department of Obstetrics and Gynecology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, Henan, China
| | - Liu Ning
- The Genetics and Prenatal Diagnosis Center, The Department of Obstetrics and Gynecology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, Henan, China
| | - Kong Xiangdong
- The Genetics and Prenatal Diagnosis Center, The Department of Obstetrics and Gynecology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, Henan, China.
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109
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Klaassen K, Djordjevic M, Skakic A, Kecman B, Drmanac R, Pavlovic S, Stojiljkovic M. Untreated PKU patients without intellectual disability: SHANK gene family as a candidate modifier. Mol Genet Metab Rep 2021; 29:100822. [PMID: 34900593 PMCID: PMC8639809 DOI: 10.1016/j.ymgmr.2021.100822] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 11/08/2021] [Accepted: 11/09/2021] [Indexed: 11/06/2022] Open
Abstract
Phenylketonuria (PKU) is an inborn error of metabolism caused by variants in the phenylalanine hydroxylase (PAH) gene and it is characterized by excessively high levels of phenylalanine in body fluids. PKU is a paradigm for a genetic disease that can be treated and majority of developed countries have a population-based newborn screening. Thus, the combination of early diagnosis and immediate initiation of treatment has resulted in normal intelligence for treated PKU patients. Although PKU is a monogenic disease, decades of research and clinical practice have shown that the correlation between the genotype and corresponding phenotype is not simple at all. Attempts have been made to discover modifier genes for PKU cognitive phenotype but without any success so far. We conducted whole genome sequencing of 4 subjects from unrelated non-consanguineous families who presented with pathogenic mutations in the PAH gene, high blood phenylalanine concentrations and near-normal cognitive development despite no treatment. We used cross sample analysis to select genes common for more than one patient. Thus, the SHANK gene family emerged as the only relevant gene family with variants detected in 3 of 4 analyzed patients. We detected two novel variants, p.Pro1591Ala in SHANK1 and p.Asp18Asn in SHANK2, as well as SHANK2:p.Gly46Ser, SHANK2:p.Pro1388_Phe1389insLeuPro and SHANK3:p.Pro1716Thr variants that were previously described. Computational analysis indicated that the identified variants do not abolish the function of SHANK proteins. However, changes in posttranslational modifications of SHANK proteins could influence functioning of the glutamatergic synapses, cytoskeleton regulation and contribute to maintaining optimal synaptic density and number of dendritic spines. Our findings are linking SHANK gene family and brain plasticity in PKU for the first time. We hypothesize that variant SHANK proteins maintain optimal synaptic density and number of dendritic spines under high concentrations of phenylalanine and could have protective modifying effect on cognitive development of PKU patients.
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Affiliation(s)
- K Klaassen
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - M Djordjevic
- Mother and Child Health Care Institute of Serbia "Dr Vukan Cupic", Belgrade, Serbia.,School of Medicine, University of Belgrade, Belgrade, Serbia
| | - A Skakic
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - B Kecman
- Mother and Child Health Care Institute of Serbia "Dr Vukan Cupic", Belgrade, Serbia
| | - R Drmanac
- Complete Genomics Incorporated, San Jose, California 95134, USA.,MGI, BGI-Shenzhen, Shenzhen 518083, China.,BGI-Shenzhen, Shenzhen 518083, China
| | - S Pavlovic
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - M Stojiljkovic
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
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110
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Bernstein L, Hansen J, Kogelmann C, Ellerbrok M, Giżewska M, Gaughan S, Rocha JC, Belanger-Quintana A, Rohr F. Normalizing Diet in Individuals with Phenylketonuria Treated with Pegvaliase: A Case Series and Patient Perspective. NUTRITION AND DIETARY SUPPLEMENTS 2021. [DOI: 10.2147/nds.s337135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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111
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Collaco JM, Raraigh KS, Betz J, Aksit MA, Blau N, Brown J, Dietz HC, MacCarrick G, Nogee LM, Sheridan MB, Vernon HJ, Beaty TH, Louis TA, Cutting GR. Accurate assignment of disease liability to genetic variants using only population data. Genet Med 2021; 24:87-99. [PMID: 34906463 DOI: 10.1016/j.gim.2021.08.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 07/23/2021] [Accepted: 08/17/2021] [Indexed: 10/19/2022] Open
Abstract
PURPOSE The growing size of public variant repositories prompted us to test the accuracy of pathogenicity prediction of DNA variants using population data alone. METHODS Under the a priori assumption that the ratio of the prevalence of variants in healthy population vs that in affected populations form 2 distinct distributions (pathogenic and benign), we used a Bayesian method to assign probability to a variant belonging to either distribution. RESULTS The approach, termed Bayesian prevalence ratio (BayPR), accurately parsed 300 of 313 expertly curated CFTR variants: 284 of 296 pathogenic/likely pathogenic variants in 1 distribution and 16 of 17 benign/likely benign variants in another. BayPR produced an area under the receiver operating characteristic curve of 0.99 for 103 functionally confirmed missense CFTR variants, which is equal to or exceeds 10 commonly used algorithms (area under the receiver operating characteristic curve range = 0.54-0.99). Application of BayPR to expertly curated variants in 8 genes associated with 7 Mendelian conditions led to the assignment of a disease-causing probability of ≥80% to 1350 of 1374 (98.3%) pathogenic/likely pathogenic variants and of ≤20% to 22 of 23 (95.7%) benign/likely benign variants. CONCLUSION Irrespective of the variant type or functional effect, the BayPR approach provides probabilities of pathogenicity for DNA variants responsible for Mendelian disorders using only the variant counts in affected and unaffected population samples.
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Affiliation(s)
- Joseph M Collaco
- Eudowood Division of Pediatric Respiratory Sciences, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Karen S Raraigh
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Joshua Betz
- Department of Biostatistics, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD
| | - Melis Atalar Aksit
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Nenad Blau
- Division of Metabolism, University Children's Hospital Zürich, Zürich, Switzerland
| | - Jordan Brown
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Harry C Dietz
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD; Howard Hughes Medical Institute, Chevy Chase, MD
| | - Gretchen MacCarrick
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Lawrence M Nogee
- Eudowood Neonatal Pulmonary Division, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Molly B Sheridan
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Hilary J Vernon
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Terri H Beaty
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD
| | - Thomas A Louis
- Department of Biostatistics, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD
| | - Garry R Cutting
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD.
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Burlina A, Biasucci G, Carbone MT, Cazzorla C, Paci S, Pochiero F, Spada M, Tummolo A, Zuvadelli J, Leuzzi V. Italian national consensus statement on management and pharmacological treatment of phenylketonuria. Orphanet J Rare Dis 2021; 16:476. [PMID: 34784942 PMCID: PMC8594187 DOI: 10.1186/s13023-021-02086-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 10/13/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Phenylketonuria (PKU) is a rare inherited metabolic disorder caused by defects in the phenylalanine-hydroxylase gene (PAH), the enzyme catalyzing the conversion of phenylalanine to tyrosine. PAH impairment causes phenylalanine accumulation in the blood and brain, with a broad spectrum of pathophysiological and neurological consequences for patients. Prevalence of disease varies, with peaks in some regions and countries, including Italy. A recent expert survey described the real-life of clinical practice for PKU in Italy, revealing inhomogeneities in disease management, particularly concerning approach to pharmacotherapy with sapropterin hydrochloride, analogous of the natural PAH co-factor, allowing disease control in a subset of patients. Therefore, the purpose of this paper is to continue the work initiated with the expert survey paper, to provide national guidances aiming to harmonize and optimize patient care at a national level. PARTICIPANTS The Consensus Group, convened by 10 Steering Committee members, consisted of a multidisciplinary crowd of 46 experts in the management of PKU in Italy. CONSENSUS PROCESS The Steering Committee met in a series of virtual meeting in order to discuss on clinical focuses to be developed and analyzed in guidance statements, on the basis of expert practice based evidence, large systematic literature review previously performed in the expert survey paper, and evidence based consensus published. Statements were re-discussed and refined during consensus conferences in the widest audience of experts, and finally submitted to the whole consensus group for a modified-Delphi voting. RESULTS Seventy three statements, divided in two main clinical areas, PKU management and Pharmacotherapy, achieved large consensus in a multidisciplinary group of expert in different aspects of disease. Importantly, these statements involve guidances for the use of sapropterin dihydrochloride, still not sufficiently implemented in Italy, and a set of good practice to approach the use of novel enzyme replacement treatment pegvaliase. CONCLUSIONS This evidence-based consensus provides a minimum set of guidances for disease management to be implemented in all PKU centers. Moreover, these guidances represent the first statement for sapropterin dihydrochloride use, implementation and standardization in Italy, and a guide for approaching pegvaliase treatment at a national level on a consistent basis.
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Affiliation(s)
- Alberto Burlina
- Division of Inherited Metabolic Diseases, Reference Center for Expanded Newborn Screening, DIDAS Servizi Di Diagnostica Integrata, University Hospital Padova, 35128, Padua, Italy
| | - Giacomo Biasucci
- Maternal and Child Health Department, Pediatrics and Neonatology Unit, Guglielmo da Saliceto Hospital, 29121, Piacenza, Italy.
| | - Maria Teresa Carbone
- Pediatric Division, Metabolic and Rare Diseases, Santobono Pausilipon Hospital, 80122, Naples, Italy
| | - Chiara Cazzorla
- Division of Inherited Metabolic Diseases, Reference Center for Expanded Newborn Screening, DIDAS Servizi Di Diagnostica Integrata, University Hospital Padova, 35128, Padua, Italy
| | - Sabrina Paci
- Paediatric Department, ASST Santi Paolo E Carlo, San Paolo Hospital, University of Milan, 20142, Milan, Italy
| | - Francesca Pochiero
- Metabolic and Muscular Unit, A. Meyer Children's Hospital, Florence, Italy
| | - Marco Spada
- Department of Pediatrics, Regina Margherita Children's Hospital, University of Torino, 10126, Turin, Italy
| | - Albina Tummolo
- Metabolic Diseases Department, Clinical Genetics and Diabetology, Giovanni XXIII Children's Hospital, 70126, Bari, Italy
| | - Juri Zuvadelli
- Paediatric Department, ASST Santi Paolo E Carlo, San Paolo Hospital, University of Milan, 20142, Milan, Italy
| | - Vincenzo Leuzzi
- Department of Human Neuroscience, Unit of Child Neurology and Psychiatry, University La Sapienza, 00185, Rome, Italy
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113
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Zamani R, Karimi-Shahanjarini A, Tapak L, Moeini B. Improving phenylalanine and micronutrients status of children with phenylketonuria: a pilot randomized study. Orphanet J Rare Dis 2021; 16:475. [PMID: 34772434 PMCID: PMC8588614 DOI: 10.1186/s13023-021-02094-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 10/17/2021] [Indexed: 11/10/2022] Open
Abstract
Background Children with Phenylketonuria (PKU) need a special diet to avoid a variety of physical and psychological complications. The aim of this study was to compare and assess the effects of two interventions on and levels of phenylalanine and micronutrients in children with PKU. Methods Forty-six children with PKU (ages 1–12 years) and their caregivers were randomly assigned to one of two 10-week interventions: a caregiver educational intervention based on the Integrative Model of Behvioral Prediction (IMBP) and supplementary low-protein-modified foods. Outcomes consisted of Children's plasma phenylalanine and micronutrients (i.e., vitamin B12, vitamin D3, and zinc) and hemoglobin levels. To assess the sustainability of outcomes, we also compared the children’s phenylalanine level at five-time points including baseline and 10-week, 6 months, 12 months, and 24 months follow-ups. In addition, caregivers of both groups were asked to complete a questionnaire to assess how well the interventions were implemented as well as satisfaction with interventions. Results While a large percentage of children had phenylalanine levels out of range indicating non-adherence (69.6% and 81% in the educational and food items group, respectively), micronutrient deficiencies were not prevalent in the patient cohort. The levels of phenylalanine in both groups decreased significantly over time. However, conducting a repeated-measures ANOVA to evaluating the change in groups across five-time points, revealed a significant difference between groups (F = 4.68, p = 0.03). That is, the educational intervention was more effective in lowering the children's phenylalanine level. At 24-month follow-up, the percentage of children with a normal range of phenylalanine level in the educational and food items groups increased to 73.9 and 57.1 percent, respectively, from 26 and 38 percent at baseline. There were no significant changes in children's micronutrients level following the interventions, except in the hemoglobin. In this way, at 10-week follow-up, the mean hemoglobin of children in the educational group reduced significantly (P = 0.041). However, there was no significant difference between the two groups. In general, all caregivers completed the process evaluation checklist, the feedback was largely positive. Conclusions The results of this study demonstrated that both educational and providing food item interventions resulted in a significant reduction in phenylalanine levels. Empowering caregivers of patients, creating and fortifying social networks, providing favorable social supports, and providing access to special food items may be effective in controlling PKU. Clinical trial registration: Iranian Registry of Clinical Trials (IRCT20180506039548N1). Registered 6th Jun 2018, https://www.irct.ir/trial/30977. Supplementary Information The online version contains supplementary material available at 10.1186/s13023-021-02094-8.
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Affiliation(s)
- Reza Zamani
- Department of Public Health, School of Public Health, Hamadan University of Medical Sciences, Shaheed Fahmideh Ave., Hamadan, Iran
| | - Akram Karimi-Shahanjarini
- Department of Public Health, School of Public Health, Hamadan University of Medical Sciences, Shaheed Fahmideh Ave., Hamadan, Iran. .,Social Determinants of Health Research Center, Hamadan University of Medical Sciences, Hamadan, Iran.
| | - Leili Tapak
- Department of Biostatistics, School of Public Health, Modeling of Noncommunicable Diseases Research Center, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Babak Moeini
- Department of Public Health, School of Public Health, Hamadan University of Medical Sciences, Shaheed Fahmideh Ave., Hamadan, Iran.,Social Determinants of Health Research Center, Hamadan University of Medical Sciences, Hamadan, Iran
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114
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Jin X, Yan Y, Zhang C, Tai Y, An L, Yu X, Zhang L, Hao S, Cao X, Yin C, Ma X. Identification of novel deep intronic PAH gene variants in patients diagnosed with phenylketonuria. Hum Mutat 2021; 43:56-66. [PMID: 34747549 DOI: 10.1002/humu.24292] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 10/21/2021] [Accepted: 10/28/2021] [Indexed: 12/17/2022]
Abstract
Phenylketonuria (PKU) is caused by phenylalanine hydroxylase (PAH) gene variants. Previously, 94.21% of variants were identified using Sanger sequencing and multiplex ligation-dependent probe amplification. To investigate the remaining variants, we performed whole-genome sequencing for four patients with PKU and unknown genotypes to identify deep intronic or structural variants. We identified three novel heterozygous variants (c.706+368T>C, c.1065+241C>A, and c.1199+502A>T) in a deep PAH gene intron. We detected a c.1199+502A>T variant in 60% (6/10) of PKU patients with genetically undetermined PKU. In silico predictions indicated that the three deep variants may impact splice site selection and result in the inclusion of a pseudo-exon. A c.1199+502A>T PAH minigene and reverse transcription PCR (RT-PCR) on blood RNA from a PKU patient with biallelic variants c.1199+502A>T and c.1199G>A confirmed that the c.1199+502A>T variant may strengthen the predicted branch point and leads to the inclusion of a 25-nt pseudo-exon in the PAH mRNA. Reverse transcription polymerase chain reaction (RT-PCR) on the minigene revealed that c.706+368T>C may create an SRSF2 (SC35) binding site via a 313-nt pseudo-exon, whereas c.1065+241C>A may produce an 81-nt pseudo-exon that strengthens the predicted SRSF1 (SF2/ASF) binding site. These results augment current knowledge of PAH genotypes and show that deep intronic analysis of PAH can genetically diagnose PKU.
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Affiliation(s)
- Xiaohua Jin
- National Research Institute for Family Planning, Beijing, China.,National Human Genetic Resources Center, Beijing, China
| | - Yousheng Yan
- Prenatal Diagnostic Center, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing, China
| | - Chuan Zhang
- National Research Institute for Family Planning, Beijing, China.,National Human Genetic Resources Center, Beijing, China.,Gansu Province Medical Genetics Center, Gansu Provincial Maternity and Child-Care Hospital, Lanzhou, China
| | - Ya Tai
- Department of Obstetrics and Gynecology, Peking University International Hospital, Beijing, China
| | - Lisha An
- National Research Institute for Family Planning, Beijing, China.,National Human Genetic Resources Center, Beijing, China
| | - Xinyou Yu
- Department of Prenatal Diagnosis Center, General Hospital of Ningxia Medical University, Yinchuan, China
| | - Linlin Zhang
- Clinical Lab, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Shengju Hao
- Gansu Province Medical Genetics Center, Gansu Provincial Maternity and Child-Care Hospital, Lanzhou, China
| | - Xiaofang Cao
- National Research Institute for Family Planning, Beijing, China.,National Human Genetic Resources Center, Beijing, China
| | - Chenghong Yin
- Prenatal Diagnostic Center, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing, China
| | - Xu Ma
- National Research Institute for Family Planning, Beijing, China.,National Human Genetic Resources Center, Beijing, China
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Vela-Amieva M, Alcántara-Ortigoza MA, Ibarra-González I, González-del Angel A, Fernández-Hernández L, Guillén-López S, López-Mejía L, Carrillo-Nieto RI, Belmont-Martínez L, Fernández-Lainez C. An Updated PAH Mutational Spectrum of Phenylketonuria in Mexican Patients Attending a Single Center: Biochemical, Clinical-Genotyping Correlations. Genes (Basel) 2021; 12:genes12111676. [PMID: 34828281 PMCID: PMC8620669 DOI: 10.3390/genes12111676] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 10/18/2021] [Accepted: 10/19/2021] [Indexed: 11/21/2022] Open
Abstract
Establishing the genotypes of patients with hyperphenylalaninemia (HPA)/phenylketonuria (PKU, MIM#261600) has been considered a cornerstone for rational medical management. However, knowledge of the phenylalanine hydroxylase gene (PAH) mutational spectrum in Latin American populations is still limited. Herein, we aim to update the mutational PAH spectrum in the largest cohort of HPA/PKU Mexican patients (N = 124) reported to date. The biallelic PAH genotype was investigated by Sanger automated sequencing, and genotypes were correlated with documented biochemical phenotypes and theoretical tetrahydrobiopterin (BH4) responsiveness. Patients were biochemically classified as having classic PKU (50%, 62/124), mild PKU (20.2%, 25/124) and mild HPA (29.8%, 37/124). Furthermore, 78.2% of the included patients (97/124) were identified by newborn screening. A total of 60 different pathogenic variants were identified, including three novel ones (c. 23del, c. 625_626insC and c. 1315 + 5_1315 + 6insGTGTAACAG), the main categories being missense changes (58%, 35/60) and those affecting the catalytic domain (56.6%, 34/60), and c. 60 + 5G > T was the most frequent variant (14.5%, 36/248) mainly restricted (69.2%) to patients from the central and western parts of Mexico. These 60 types of variants constituted 100 different biallelic PAH genotypes, with the predominance of compound-heterozygous ones (96/124, 77%). The expected BH4 responsiveness based on the PAH genotype was estimated in 52% of patients (65/124), mainly due to the p. (Val388Met) (rs62516101) allele. Instead, our study identified 27 null variants with an allelic phenotype value of zero, with a predominance of c. 60 + 5G > T, which predicts the absence of BH4 responsiveness. An identical genotype reported in BIOPKUdb was found in 92/124 (74%) of our patients, leading to a genotype–phenotype concordance in 80/92 (86.9%) of them. The high number of variants found confirms the heterogeneous and complex mutational landscape of HPA/PKU in Mexico.
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Affiliation(s)
- Marcela Vela-Amieva
- Laboratorio de Errores Innatos del Metabolismo y Tamiz, Subdirección de Medicina Experimental, Instituto Nacional de Pediatría, Secretaría de Salud, Ciudad de Mexico 04530, Mexico; (M.V.-A.); (S.G.-L.); (L.L.-M.); (R.I.C.-N.); (L.B.-M.)
| | - Miguel Angel Alcántara-Ortigoza
- Laboratorio de Biología Molecular, Subdirección de Investigación Médica, Instituto Nacional de Pediatría, Secretaría de Salud, Ciudad de Mexico 04530, Mexico; (M.A.A.-O.); (A.G.-d.A.); (L.F.-H.)
| | - Isabel Ibarra-González
- Unidad de Genética de la Nutrición, Instituto de Investigaciones Biomédicas, UNAM/Instituto Nacional de Pediatría, Ciudad de Mexico 04530, Mexico;
| | - Ariadna González-del Angel
- Laboratorio de Biología Molecular, Subdirección de Investigación Médica, Instituto Nacional de Pediatría, Secretaría de Salud, Ciudad de Mexico 04530, Mexico; (M.A.A.-O.); (A.G.-d.A.); (L.F.-H.)
| | - Liliana Fernández-Hernández
- Laboratorio de Biología Molecular, Subdirección de Investigación Médica, Instituto Nacional de Pediatría, Secretaría de Salud, Ciudad de Mexico 04530, Mexico; (M.A.A.-O.); (A.G.-d.A.); (L.F.-H.)
| | - Sara Guillén-López
- Laboratorio de Errores Innatos del Metabolismo y Tamiz, Subdirección de Medicina Experimental, Instituto Nacional de Pediatría, Secretaría de Salud, Ciudad de Mexico 04530, Mexico; (M.V.-A.); (S.G.-L.); (L.L.-M.); (R.I.C.-N.); (L.B.-M.)
| | - Lizbeth López-Mejía
- Laboratorio de Errores Innatos del Metabolismo y Tamiz, Subdirección de Medicina Experimental, Instituto Nacional de Pediatría, Secretaría de Salud, Ciudad de Mexico 04530, Mexico; (M.V.-A.); (S.G.-L.); (L.L.-M.); (R.I.C.-N.); (L.B.-M.)
| | - Rosa Itzel Carrillo-Nieto
- Laboratorio de Errores Innatos del Metabolismo y Tamiz, Subdirección de Medicina Experimental, Instituto Nacional de Pediatría, Secretaría de Salud, Ciudad de Mexico 04530, Mexico; (M.V.-A.); (S.G.-L.); (L.L.-M.); (R.I.C.-N.); (L.B.-M.)
| | - Leticia Belmont-Martínez
- Laboratorio de Errores Innatos del Metabolismo y Tamiz, Subdirección de Medicina Experimental, Instituto Nacional de Pediatría, Secretaría de Salud, Ciudad de Mexico 04530, Mexico; (M.V.-A.); (S.G.-L.); (L.L.-M.); (R.I.C.-N.); (L.B.-M.)
| | - Cynthia Fernández-Lainez
- Laboratorio de Errores Innatos del Metabolismo y Tamiz, Subdirección de Medicina Experimental, Instituto Nacional de Pediatría, Secretaría de Salud, Ciudad de Mexico 04530, Mexico; (M.V.-A.); (S.G.-L.); (L.L.-M.); (R.I.C.-N.); (L.B.-M.)
- Correspondence: ; Tel.: +52-1-55-10840900 (ext. 1332)
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Su Y, Shadike Q, Wang M, Jiang H, Liu W, Liu J, Tuerdi R, Zhou W, Li L. A low abundance of genus Bacteroides in gut microbiota is negatively correlated with blood phenylalanine levels in Uygur patients with phenylketonuria. Transl Pediatr 2021; 10:2521-2532. [PMID: 34765476 PMCID: PMC8578770 DOI: 10.21037/tp-21-426] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 10/09/2021] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND A low-phenylalanine (Phe) diet affects the metabolism and diversity of gut microbial communities in children with phenylketonuria (PKU). Our study examined gut microbiota characteristics and metabolic pathways, and their correlations with clinical phenotypes in a high-incidence population. METHODS We assessed clinical phenotypes and gut microbiota by 16S ribosomal RNA (rRNA) sequencing, and performed a correlation analysis between phenotype and gut microbiota in a PKU group (n=11) and a healthy group (n=11). RESULTS The PKU group had significantly lower microbiota diversity than the healthy group (Pshannon=0.014). Phylum-level composition differed significantly between the PKU and healthy groups (Firmicutes: 44.3% vs. 43.1%; Actinobacteria: 25.9% vs. 3.3%; Bacteroidetes: 16.6% vs. 53.2%; and Proteobacteria: 10.9% vs. 0.12%, respectively). Further, a significantly decreased level of genus Bacteroidetes (P<0.0001) in the PKU group was negatively correlated with blood Phe level (P=0.014). The microbial function prediction of the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways exhibited a decreased ability of glycan degradation and glutamate metabolism in the PKU group. CONCLUSIONS Our findings revealed that genus Bacteroide was not only in extremely low abundance in the PKU group, but was also negatively correlated with blood Phe level. The remarkable capability of genus Bacteroides to use complex recalcitrant glycans may be the main reason for the decreased ability of glycan degradation in the PKU group.
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Affiliation(s)
- Yajie Su
- Department of Neonatology, Children's Hospital of Fudan University, and Institutes of Biomedical Sciences, Fudan University, Shanghai, China.,Department of Neonatology, Children's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, China
| | - Qiaolibang Shadike
- Department of Neonatology, Children's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, China
| | - Mingbang Wang
- Centre for Molecular Medicine, Children's Hospital of Fudan University, Shanghai, China
| | - Haili Jiang
- Department of Neonatology, Children's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, China
| | - Wanying Liu
- Department of Neonatology, Children's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, China
| | - Jingfang Liu
- Department of Neonatology, Children's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, China
| | - Rena Tuerdi
- Department of Neonatology, Children's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, China
| | - Wenhao Zhou
- Department of Neonatology, Children's Hospital of Fudan University, and Institutes of Biomedical Sciences, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Birth Defects, Pediatrics Research Institute, Shanghai, China
| | - Long Li
- Department of Neonatology, Children's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, China.,Department of Neonatology, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, China
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117
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Çıkı K, Akar HT, Özgül RK, Gülbakan B, Yıldız Y. Perplexing Etiology of Hyperphenylalaninemia in an Infant Referred via Newborn Screening. Clin Chem 2021; 67:1428-1431. [PMID: 34597372 DOI: 10.1093/clinchem/hvab106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 05/07/2021] [Indexed: 11/13/2022]
Affiliation(s)
- Kısmet Çıkı
- Division of Pediatric Metabolism, Department of Pediatrics, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - H Tuna Akar
- Division of Pediatric Metabolism, Department of Pediatrics, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - R Köksal Özgül
- Department of Pediatric Metabolism, Institute of Child Health, Hacettepe University, Ankara, Turkey
| | - Basri Gülbakan
- Department of Pediatric Metabolism, Institute of Child Health, Hacettepe University, Ankara, Turkey
| | - Yılmaz Yıldız
- Division of Pediatric Metabolism, Department of Pediatrics, Faculty of Medicine, Hacettepe University, Ankara, Turkey
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118
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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] [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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119
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Nemati H, Yousefi SK, Pourvatan N, Aparviz R, Farzaneh P, Koohpar ZK, Safari F, Asl AS, Ranji N. Mutation analysis of phenylketonuria in the North of Iran. GENE REPORTS 2021. [DOI: 10.1016/j.genrep.2021.101196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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120
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Ramos-Álvarez R, Kapp M, Rodríguez-Ruiz MM, Fausor R, Bueno-Delgado MA, Ahring K, Waisbren SE. Adaptation and Validation of a Questionnaire to Evaluate Knowledge of the Low Phe Diet in PKU. Nutrients 2021; 13:nu13082719. [PMID: 34444879 PMCID: PMC8400675 DOI: 10.3390/nu13082719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/21/2021] [Accepted: 07/30/2021] [Indexed: 11/17/2022] Open
Abstract
Phenylketonuria (PKU) is an autosomal recessive disorder of phenylalanine (Phe) metabolism, causing a build-up of Phe in the body. Treatment consists of a Phe-restricted diet for life and regular determination of blood Phe levels to monitor the intake of Phe. Despite the fact that diet is the cornerstone of treatment, there are no studies examining common knowledge about food items and whether they are allowed as part of the PKU diet. Improving parents’ and patients’ knowledge and competence about the diet enables them to make appropriate food choices. This study validates a food-knowledge questionnaire first developed in Spanish and modified for English speaking populations. The questionnaire potentially helps parents to prepare appropriate meals and healthcare providers to create individualized educational programs about PKU for children and adolescents with this disorder.
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Affiliation(s)
- Rodolfo Ramos-Álvarez
- Department of Social Psychology, Melilla Campus, Granada University, 52005 Melilla, Spain
- Correspondence: (R.R.-Á.); (S.E.W.)
| | - Maili Kapp
- Teaching Innovation Project (Code: 14–82), Melilla Campus, Granada University, 52005 Melilla, Spain;
| | | | - Rocío Fausor
- Department of Personality, Assessment and Clinical Psychology, Complutense University of Madrid, 28223 Madrid, Spain;
| | | | - Kirsten Ahring
- Center for PKU, Copenhagen University Hospital, 2600 Copenhagen, Denmark;
| | - Susan E. Waisbren
- Genetics and Metabolism Programs, Boston Children’s Hospital, Harvard Medical School, Harvard University, Boston, MA 02115, USA
- Correspondence: (R.R.-Á.); (S.E.W.)
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121
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Çıkı K, Yıldız Y, Yücel Yılmaz D, Pektaş E, Tokatlı A, Özgül RK, Sivri HS, Dursun A. DNACJ12 deficiency in patients with unexplained hyperphenylalaninemia: two new patients and a novel variant. Metab Brain Dis 2021; 36:1405-1410. [PMID: 34014443 DOI: 10.1007/s11011-021-00753-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 05/10/2021] [Indexed: 10/21/2022]
Abstract
In addition to tetrahydrobiopterin deficiencies and phenylalanine hydroxylase deficiency (phenylketonuria) due to PAH variants, the deficiency of the co-chaperone protein DNAJC12 was identified in 2017 as a novel cause of inherited hyperphenylalaninemia, revealing the genetic etiology in previously unresolved cases. In this study, we aimed to investigate DNAJC12 deficiency in non-tetrahydrobiopterin-deficient persistent hyperphenylalaninemia cases without biallelic PAH variants in a single pediatric metabolic center. It was determined retrospectively that 471 patients with non-tetrahydrobiopterin deficiency-hyperphenylalaninemia had undergone PAH gene sequencing and 451 patients had biallelic variants in PAH. DNAJC12 sequencing was performed in the remaining 20 patients, identifying a previously reported homozygous splice-site variant (c.158-2A > T) in one patient with axial hypotonia and developmental delay, and a novel, homozygous c.404del (p.Arg135Lysfs*21) frameshift variant in an asymptomatic patient. In segregation analysis, the asymptomatic patient's both parents were also found to be homozygous for this variant and hyperphenylalaninemic. The parents may have had academic difficulties but intellectual disability could not be confirmed due to lack of cooperation. The symptomatic patient significantly benefited from treatment with sapropterin dihydrochloride and neurotransmitter precursors. DNAJC12 deficiency might be responsible for approximately 10% or more of cases with unexplained hyperphenylalaninemia. The phenotypic spectrum is broad, ranging from early infantile hypotonia to incidental diagnosis in adulthood. Similar to tetrahydrobiopterin deficiencies, early diagnosis and treatment with sapropterin dihydrochloride and neurotransmitter precursors can be beneficial, supporting the analysis of DNACJ12 gene in patients with unexplained hyperphenylalaninemia.
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Affiliation(s)
- Kısmet Çıkı
- Division of Pediatric Metabolism, Department of Pediatrics, Faculty of Medicine, Hacettepe University, Ankara, Turkey.
| | - Yılmaz Yıldız
- Division of Pediatric Metabolism, Department of Pediatrics, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - Didem Yücel Yılmaz
- Department of Pediatric Metabolism, Institute of Child Health, Hacettepe University, Ankara, Turkey
| | - Emine Pektaş
- Pediatric Metabolic Diseases Unit, Gaziantep Cengiz Gökçek Maternity and Pediatrics Hospital, Gaziantep, Turkey
| | - Ayşegül Tokatlı
- Division of Pediatric Metabolism, Department of Pediatrics, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - R Köksal Özgül
- Department of Pediatric Metabolism, Institute of Child Health, Hacettepe University, Ankara, Turkey
| | - H Serap Sivri
- Division of Pediatric Metabolism, Department of Pediatrics, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - Ali Dursun
- Division of Pediatric Metabolism, Department of Pediatrics, Faculty of Medicine, Hacettepe University, Ankara, Turkey
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Capalbo A, Fabiani M, Caroselli S, Poli M, Girardi L, Patassini C, Favero F, Cimadomo D, Vaiarelli A, Simon C, Rienzi LF, Ubaldi FM. Clinical validity and utility of preconception expanded carrier screening for the management of reproductive genetic risk in IVF and general population. Hum Reprod 2021; 36:2050-2061. [PMID: 34021342 DOI: 10.1093/humrep/deab087] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 03/15/2021] [Indexed: 11/14/2022] Open
Abstract
STUDY QUESTION What is the clinical validity and utility of preconception Expanded Carrier Screening (ECS) application on the management of prospective parents? SUMMARY ANSWER The high detection rate of at-risk couples (ARCs) and the high proportion opting for IVF/preimplantation genetic testing (PGT) treatment demonstrate the clinical utility of ECS in the preconception space in IVF and general population. WHAT IS KNOWN ALREADY About 2-4% of couples are at risk of conceiving a child with an autosomal recessive or X-linked genetic disorder. In recent years, the increasing cost-effectiveness of genetic diagnostic techniques has allowed the creation of ECS panels for the simultaneous detection of multiple recessive disorders. Comprehensive preconception genetic screening holds the potential to significantly improve couple's genetic risk assessment and reproductive planning to avoid detectable inheritable genetic offspring. STUDY DESIGN, SIZE, DURATION A total of 3877 individuals without a family history of genetic conditions were analyzed between January 2017 and January 2020. Of the enrolled individuals, 1212 were gamete donors and 2665 were patients planning on conceiving from both the IVF and the natural conception group. From the non-donor cohort, 1133 were analyzed as individual patients, while the remaining ones were analyzed as couples, for a total of 766 couples. PARTICIPANTS/MATERIALS, SETTING, METHODS A focused ECS panel was developed following American College of Obstetrics and Gynecology ACOG-recommended criteria (prevalence, carrier rate, severity), including highly penetrant severe childhood conditions. Couples were defined at-risk when both partners carried an autosomal recessive pathogenic/likely pathogenic variant (PLP) on the same gene or when the woman was a carrier of an X-linked PLP variant. ARC detection rate defined the clinical validity of the ECS approach. Clinical utility was evaluated by monitoring ARCs reproductive decision making. MAIN RESULTS AND THE ROLE OF CHANCE A total of 402 individuals (10.4%) showed PLP for at least one of the genes tested. Among the 766 couples tested, 173 showed one carrier partner (22.6%), whereas 20 couples (2.6%) were found to be at increased risk. Interestingly, one ARC was identified as a result of cascade testing in the extended family of an individual carrying a pathogenic variant on the Survival Of Motor Neuron 1SMN1 gene. Of the identified ARCs, 5 (0.7%) were at risk for cystic fibrosis, 5 (0.7%) for fragile X syndrome, 4 (0.5%) for spinal muscular atrophy, 4 (0.5%) for Beta-Thalassemia/Sickle Cell Anemia, 1 (0.1%) for Smith-Lemli-Opitz Syndrome and 1 (0.1%) for Duchenne/Becker Dystrophy. Fifteen ARCs were successfully followed up from both the IVF and the natural conception groups. All of these (15/15) modified their reproductive planning by undergoing ART with Preimplantation Genetic Testing for Monogenic disease and Aneuploidies (PGT-M and PGT-A). To date, 6/15 (40%) couples completed their PGT cycle with euploid/unaffected embryos achieving a pregnancy after embryo transfer and three of them have already had an unaffected baby. LIMITATIONS, REASONS FOR CAUTION The use of a limited panel of core gene-disease pairs represents a limitation on the research perspective as it can underestimate the rate of detectable carriers and ARCs in this cohort of prospective parents. Expanding the scope of ECS to a larger panel of conditions is becoming increasingly feasible, thanks to a persistent technological evolution and progressive cataloging of gene-disease associations. WIDER IMPLICATIONS OF THE FINDINGS These results highlight the potential clinical validity and utility of ECS in reducing the risk of a pregnancy affected by a detectable inheritable genetic condition. The steady reduction in the costs of genetic analyses enables the expansion of monogenic testing/screening applications at the preimplantation stage, thus, providing valid decisional support and reproductive autonomy to patients, particularly in the context of IVF. STUDY FUNDING/COMPETING INTEREST(S) No external funding was used for this study. A.C., M.F., S.C., M.P., L.G., and C.P. are employees of Igenomix Italy. C.S. is the head of the scientific board of Igenomix. TRIAL REGISTRATION NUMBER N/A.
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Affiliation(s)
- A Capalbo
- Igenomix Italy, Marostica, Italy.,Igenomix Foundation, INCLIVA, Valencia, Spain
| | | | | | - M Poli
- Igenomix Italy, Marostica, Italy
| | | | | | | | - D Cimadomo
- GeneraLife, Center for Reproductive Medicine, Clinica Valle Giulia, Rome, Italy
| | - A Vaiarelli
- GeneraLife, Center for Reproductive Medicine, Clinica Valle Giulia, Rome, Italy
| | - C Simon
- Igenomix Italy, Marostica, Italy.,Igenomix Foundation, INCLIVA, Valencia, Spain.,Department of Obstetrics and Gynecology, University of Valencia, Valencia, Spain.,Department of Obstetrics and Gynecology BIDMC, Harvard University, Cambridge, MA, USA
| | - L F Rienzi
- GeneraLife, Center for Reproductive Medicine, Clinica Valle Giulia, Rome, Italy
| | - F M Ubaldi
- GeneraLife, Center for Reproductive Medicine, Clinica Valle Giulia, Rome, Italy
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Foreman PK, Margulis AV, Alexander K, Shediac R, Calingaert B, Harding A, Pladevall-Vila M, Landis S. Birth prevalence of phenylalanine hydroxylase deficiency: a systematic literature review and meta-analysis. Orphanet J Rare Dis 2021; 16:253. [PMID: 34082800 PMCID: PMC8173927 DOI: 10.1186/s13023-021-01874-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 05/20/2021] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Phenylalanine hydroxylase (PAH) deficiency is an autosomal recessive disorder that results in elevated concentrations of phenylalanine (Phe) in the blood. If left untreated, the accumulation of Phe can result in profound neurocognitive disability. The objective of this systematic literature review and meta-analysis was to estimate the global birth prevalence of PAH deficiency from newborn screening studies and to estimate regional differences, overall and for various clinically relevant Phe cutoff values used in confirmatory testing. METHODS The protocol for this literature review was registered with PROSPERO (International prospective register of systematic reviews). Pubmed and Embase database searches were used to identify studies that reported the birth prevalence of PAH deficiency. Only studies including numeric birth prevalence reports of confirmed PAH deficiency were included. RESULTS From the 85 publications included in the review, 238 birth prevalence estimates were extracted. After excluding prevalence estimates that did not meet quality assessment criteria or because of temporal and regional overlap, estimates from 45 publications were included in the meta-analysis. The global birth prevalence of PAH deficiency, estimated by weighting regional birth prevalences relative to their share of the population of all regions included in the study, was 0.64 (95% confidence interval [CI] 0.53-0.75) per 10,000 births and ranged from 0.03 (95% CI 0.02-0.05) per 10,000 births in Southeast Asia to 1.18 (95% CI 0.64-1.87) per 10,000 births in the Middle East/North Africa. Regionally weighted global birth prevalences per 10,000 births by confirmatory test Phe cutoff values were 0.96 (95% CI 0.50-1.42) for the Phe cutoff value of 360 ± 100 µmol/L; 0.50 (95% CI 0.37-0.64) for the Phe cutoff value of 600 ± 100 µmol/L; and 0.30 (95% CI 0.20-0.40) for the Phe cutoff value of 1200 ± 200 µmol/L. CONCLUSIONS Substantial regional variation in the birth prevalence of PAH deficiency was observed in this systematic literature review and meta-analysis of published evidence from newborn screening. The precision of the prevalence estimates is limited by relatively small sample sizes, despite widespread and longstanding newborn screening in much of the world.
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Affiliation(s)
- Pamela K Foreman
- BioMarin Pharmaceutical Inc, 770 Lindaro Street, San Rafael, CA, 94901, USA
| | - Andrea V Margulis
- RTI Health Solutions, Barcelona, Av. Diagonal 605, 9-4, 08028, Barcelona, Spain
| | - Kimberly Alexander
- BioMarin Pharmaceutical Inc, 770 Lindaro Street, San Rafael, CA, 94901, USA
| | - Renee Shediac
- BioMarin Pharmaceutical Inc, 770 Lindaro Street, San Rafael, CA, 94901, USA
| | - Brian Calingaert
- RTI Health Solutions, North Carolina, 3040 East Cornwallis Road, P.O. Box 12194, Research Triangle Park, NC, 27709-2194, USA
| | - Abenah Harding
- RTI Health Solutions, North Carolina, 3040 East Cornwallis Road, P.O. Box 12194, Research Triangle Park, NC, 27709-2194, USA
| | | | - Sarah Landis
- BioMarin (U.K.) Limited, 10 Bloomsbury Way, London, WC1A 2SL, UK.
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Abstract
Phenylketonuria (PKU; also known as phenylalanine hydroxylase (PAH) deficiency) is an autosomal recessive disorder of phenylalanine metabolism, in which especially high phenylalanine concentrations cause brain dysfunction. If untreated, this brain dysfunction results in severe intellectual disability, epilepsy and behavioural problems. The prevalence varies worldwide, with an average of about 1:10,000 newborns. Early diagnosis is based on newborn screening, and if treatment is started early and continued, intelligence is within normal limits with, on average, some suboptimal neurocognitive function. Dietary restriction of phenylalanine has been the mainstay of treatment for over 60 years and has been highly successful, although outcomes are still suboptimal and patients can find the treatment difficult to adhere to. Pharmacological treatments are available, such as tetrahydrobiopterin, which is effective in only a minority of patients (usually those with milder PKU), and pegylated phenylalanine ammonia lyase, which requires daily subcutaneous injections and causes adverse immune responses. Given the drawbacks of these approaches, other treatments are in development, such as mRNA and gene therapy. Even though PAH deficiency is the most common defect of amino acid metabolism in humans, brain dysfunction in individuals with PKU is still not well understood and further research is needed to facilitate development of pathophysiology-driven treatments.
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Affiliation(s)
- Francjan J van Spronsen
- Beatrix Children's Hospital, University Medical Centre Groningen, University of Groningen, Groningen, Netherlands.
| | - Nenad Blau
- University Children's Hospital in Zurich, Zurich, Switzerland
| | - Cary Harding
- Department of Molecular and Medical Genetics and Department of Pediatrics, Oregon Health & Science University, Oregon, USA
| | | | - Nicola Longo
- Department of Pediatrics, University of Utah, Salt Lake City, Utah, USA
| | - Annet M Bosch
- University of Amsterdam, Department of Pediatrics, Division of Metabolic Disorders, Emma Children's Hospital, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
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Wang X, Wang Y, Ma D, Zhang Z, Li Y, Yang P, Sun Y, Jiang T. Neonatal screening and genotype-phenotype correlation of hyperphenylalaninemia in the Chinese population. Orphanet J Rare Dis 2021; 16:214. [PMID: 33980295 PMCID: PMC8114530 DOI: 10.1186/s13023-021-01846-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 05/04/2021] [Indexed: 11/10/2022] Open
Abstract
Background Hyperphenylalaninemia (HPA) is the most common amino acid metabolic disease involving phenylalanine hydroxylase (PAH, OMIM*612,349) deficiency or coenzyme tetrahydrobiopterin (BH4) deficiency. Patients with severe HPA often have a difficult life. Early diagnosis of HPA before the development of symptoms is possible via neonatal screening, facilitating appropriate treatment and reducing mortality and disability rates. This study revealed the prevalence, mutational and phenotypic spectrum, and prognosis of HPA by neonatal screening from January 2001 to September 2020 in Nanjing, Jiangsu Province, China. Methods Through a retrospective analysis of the information available in the neonatal screening database, the clinical presentations, laboratory data, molecular characteristics and treatment follow-up data of HPA patients detected by neonatal screening were evaluated. Results We diagnosed 181 patients with HPA from 1 to 957 newborns, giving an incidence of 1:6873. Among these patients, 177 were identified as PAH deficient and four patients were BH4 deficient. The average current age of the patients was 6.38 years old. The most common mutations of PAH were c.728 C > A/ p.Arg243Gln (13.83 %), c.158G > A/ p.Arg53His (9.57 %), c.611 A > G/ p.Tyr204Cys (7.44 %), and c.721 C > T/ p.Arg241Cys (6.38 %). Conclusions This study revealed the prevalence, phenotype-genotype, and prognosis of HPA in China and contributes to the updating of PAHD data for China and worldwide. Our study not only expanded the spectrum of phenotypes and genotype but also provided a valuable tool for improved genetic counseling and management of future cases. Supplementary Information The online version contains supplementary material available at 10.1186/s13023-021-01846-w.
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Affiliation(s)
- Xin Wang
- Genetic Medicine Center, Nanjing Maternity and Child Health Care Hospital, Women's Hospital of Nanjing Medical University, 123 Tianfei St., Qinhuai District, Nanjing, 210004, People's Republic of China
| | - Yanyun Wang
- Genetic Medicine Center, Nanjing Maternity and Child Health Care Hospital, Women's Hospital of Nanjing Medical University, 123 Tianfei St., Qinhuai District, Nanjing, 210004, People's Republic of China
| | - Dingyuan Ma
- Genetic Medicine Center, Nanjing Maternity and Child Health Care Hospital, Women's Hospital of Nanjing Medical University, 123 Tianfei St., Qinhuai District, Nanjing, 210004, People's Republic of China
| | - Zhilei Zhang
- Genetic Medicine Center, Nanjing Maternity and Child Health Care Hospital, Women's Hospital of Nanjing Medical University, 123 Tianfei St., Qinhuai District, Nanjing, 210004, People's Republic of China
| | - Yahong Li
- Genetic Medicine Center, Nanjing Maternity and Child Health Care Hospital, Women's Hospital of Nanjing Medical University, 123 Tianfei St., Qinhuai District, Nanjing, 210004, People's Republic of China
| | - Peiying Yang
- Genetic Medicine Center, Nanjing Maternity and Child Health Care Hospital, Women's Hospital of Nanjing Medical University, 123 Tianfei St., Qinhuai District, Nanjing, 210004, People's Republic of China
| | - Yun Sun
- Genetic Medicine Center, Nanjing Maternity and Child Health Care Hospital, Women's Hospital of Nanjing Medical University, 123 Tianfei St., Qinhuai District, Nanjing, 210004, People's Republic of China
| | - Tao Jiang
- Genetic Medicine Center, Nanjing Maternity and Child Health Care Hospital, Women's Hospital of Nanjing Medical University, 123 Tianfei St., Qinhuai District, Nanjing, 210004, People's Republic of China.
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Hoytema van Konijnenburg EMM, Wortmann SB, Koelewijn MJ, Tseng LA, Houben R, Stöckler-Ipsiroglu S, Ferreira CR, van Karnebeek CDM. Treatable inherited metabolic disorders causing intellectual disability: 2021 review and digital app. Orphanet J Rare Dis 2021; 16:170. [PMID: 33845862 PMCID: PMC8042729 DOI: 10.1186/s13023-021-01727-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 02/03/2021] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND The Treatable ID App was created in 2012 as digital tool to improve early recognition and intervention for treatable inherited metabolic disorders (IMDs) presenting with global developmental delay and intellectual disability (collectively 'treatable IDs'). Our aim is to update the 2012 review on treatable IDs and App to capture the advances made in the identification of new IMDs along with increased pathophysiological insights catalyzing therapeutic development and implementation. METHODS Two independent reviewers queried PubMed, OMIM and Orphanet databases to reassess all previously included disorders and therapies and to identify all reports on Treatable IDs published between 2012 and 2021. These were included if listed in the International Classification of IMDs (ICIMD) and presenting with ID as a major feature, and if published evidence for a therapeutic intervention improving ID primary and/or secondary outcomes is available. Data on clinical symptoms, diagnostic testing, treatment strategies, effects on outcomes, and evidence levels were extracted and evaluated by the reviewers and external experts. The generated knowledge was translated into a diagnostic algorithm and updated version of the App with novel features. RESULTS Our review identified 116 treatable IDs (139 genes), of which 44 newly identified, belonging to 17 ICIMD categories. The most frequent therapeutic interventions were nutritional, pharmacological and vitamin and trace element supplementation. Evidence level varied from 1 to 3 (trials, cohort studies, case-control studies) for 19% and 4-5 (case-report, expert opinion) for 81% of treatments. Reported effects included improvement of clinical deterioration in 62%, neurological manifestations in 47% and development in 37%. CONCLUSION The number of treatable IDs identified by our literature review increased by more than one-third in eight years. Although there has been much attention to gene-based and enzyme replacement therapy, the majority of effective treatments are nutritional, which are relatively affordable, widely available and (often) surprisingly effective. We present a diagnostic algorithm (adjustable to local resources and expertise) and the updated App to facilitate a swift and accurate workup, prioritizing treatable IDs. Our digital tool is freely available as Native and Web App (www.treatable-id.org) with several novel features. Our Treatable ID endeavor contributes to the Treatabolome and International Rare Diseases Research Consortium goals, enabling clinicians to deliver rapid evidence-based interventions to our rare disease patients.
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Affiliation(s)
| | - Saskia B Wortmann
- Department of Pediatrics, Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
- University Children's Hospital, Paracelsus Medical University, Salzburg, Austria
- On Behalf of United for Metabolic Diseases, Amsterdam, The Netherlands
| | - Marina J Koelewijn
- Department of Pediatrics, Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Laura A Tseng
- Department of Pediatrics, Amsterdam UMC, Amsterdam, The Netherlands
- On Behalf of United for Metabolic Diseases, Amsterdam, The Netherlands
| | | | - Sylvia Stöckler-Ipsiroglu
- Division of Biochemical Diseases, Department of Pediatrics, BC Children's Hospital, Vancouver, BC, V6H 3V4, Canada
| | - Carlos R Ferreira
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Clara D M van Karnebeek
- Department of Pediatrics, Amsterdam UMC, Amsterdam, The Netherlands.
- Department of Pediatrics, Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.
- On Behalf of United for Metabolic Diseases, Amsterdam, The Netherlands.
- Department of Pediatrics - Metabolic Diseases, Amalia Children's Hospital, Geert Grooteplein 10, Radboud University Medical Center, 6525 GA, Nijmegen, The Netherlands.
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Bortoluzzi VT, Dutra Filho CS, Wannmacher CMD. Oxidative stress in phenylketonuria-evidence from human studies and animal models, and possible implications for redox signaling. Metab Brain Dis 2021; 36:523-543. [PMID: 33580861 DOI: 10.1007/s11011-021-00676-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 01/24/2021] [Indexed: 01/11/2023]
Abstract
Phenylketonuria (PKU) is one of the commonest inborn error of amino acid metabolism. Before mass neonatal screening was possible, and the success of introducing diet therapy right after birth, the typical clinical finds in patients ranged from intellectual disability, epilepsy, motor deficits to behavioral disturbances and other neurological and psychiatric symptoms. Since early diagnosis and treatment became widespread, usually only those patients who do not strictly follow the diet present psychiatric, less severe symptoms such as anxiety, depression, sleep pattern disturbance, and concentration and memory problems. Despite the success of low protein intake in preventing otherwise severe outcomes, PKU's underlying neuropathophysiology remains to be better elucidated. Oxidative stress has gained acceptance as a disturbance implicated in the pathogenesis of PKU. The conception of oxidative stress has evolved to comprehend how it could interfere and ultimately modulate metabolic pathways regulating cell function. We summarize the evidence of oxidative damage, as well as compromised antioxidant defenses, from patients, animal models of PKU, and in vitro experiments, discussing the possible clinical significance of these findings. There are many studies on oxidative stress and PKU, but only a few went further than showing macromolecular damage and disturbance of antioxidant defenses. In this review, we argue that these few studies may point that oxidative stress may also disturb redox signaling in PKU, an aspect few authors have explored so far. The reported effect of phenylalanine on the expression or activity of enzymes participating in metabolic pathways known to be responsive to redox signaling might be mediated through oxidative stress.
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Affiliation(s)
- Vanessa Trindade Bortoluzzi
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600-Anexo, Porto Alegre, RS, CEP 90.035-003, 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, Porto Alegre, RS, CEP 90.035-003, 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, Porto Alegre, RS, CEP 90.035-003, Brazil
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Arturo EC, Merkel GW, Hansen MR, Lisowski S, Almeida D, Gupta K, Jaffe EK. Manipulation of a cation-π sandwich reveals conformational flexibility in phenylalanine hydroxylase. Biochimie 2021; 183:63-77. [PMID: 33221376 PMCID: PMC9856217 DOI: 10.1016/j.biochi.2020.11.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 11/04/2020] [Accepted: 11/10/2020] [Indexed: 01/24/2023]
Abstract
Phenylalanine hydroxylase (PAH) is an allosteric enzyme that maintains phenylalanine (Phe) below neurotoxic levels; its failure results in phenylketonuria, an inborn error of amino acid metabolism. Wild type (WT) PAH equilibrates among resting-state (RS-PAH) and activated (A-PAH) conformations, whose equilibrium position depends upon allosteric Phe binding. The RS-PAH conformation of WT rat PAH (rPAH) contains a cation-π sandwich involving Phe80 that cannot exist in the A-PAH conformation. Phe80 variants F80A, F80D, F80L, and F80R were prepared and evaluated using native PAGE, size exclusion chromatography, ion exchange behavior, intrinsic protein fluorescence, enzyme kinetics, and limited proteolysis, each as a function of [Phe]. Like WT rPAH, F80A and F80D show allosteric activation by Phe while F80L and F80R are constitutively active. Maximal activity of all variants suggests relief of a rate-determining conformational change. Limited proteolysis of WT rPAH (minus Phe) reveals facile cleavage within a 4-helix bundle that is buried in the RS-PAH tetramer interface, reflecting dynamic dissociation of that tetramer. This cleavage is not seen for the Phe80 variants, which all show proteolytic hypersensitivity in a linker that repositions during the RS-PAH to A-PAH interchange. Hypersensitivity is corrected by addition of Phe such that all variants become like WT rPAH and achieve the A-PAH conformation. Thus, manipulation of Phe80 perturbs the conformational space sampled by PAH, increasing sampling of on-pathway intermediates in the RS-PAH and A-PAH interchange. The behavior of the Phe80 variants mimics that of disease-associated R68S and suggests a molecular basis for proteolytic susceptibility in PKU-associated human PAH variants.
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Affiliation(s)
- Emilia C. Arturo
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania, 10111,Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102
| | - George W. Merkel
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania, 10111
| | - Michael R. Hansen
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania, 10111
| | - Sophia Lisowski
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania, 10111
| | - Deeanne Almeida
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania, 10111
| | - Kushol Gupta
- Department pf Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Eileen K. Jaffe
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania, 10111,To whom correspondence should be addressed: Eileen K. Jaffe: Molecular Therapeutics, Fox Chase Cancer Center, Philadelphia, PA 19111; ; Tel.(215) 728-3695; Fax. (215) 728-2412
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Ilgaz F, Marsaux C, Pinto A, Singh R, Rohde C, Karabulut E, Gökmen-Özel H, Kuhn M, MacDonald A. Protein Substitute Requirements of Patients with Phenylketonuria on BH4 Treatment: A Systematic Review and Meta-Analysis. Nutrients 2021; 13:1040. [PMID: 33807079 PMCID: PMC8004763 DOI: 10.3390/nu13031040] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 03/12/2021] [Accepted: 03/19/2021] [Indexed: 11/16/2022] Open
Abstract
The traditional treatment for phenylketonuria (PKU) is a phenylalanine (Phe)-restricted diet, supplemented with a Phe-free/low-Phe protein substitute. Pharmaceutical treatment with synthetic tetrahydrobiopterin (BH4), an enzyme cofactor, allows a patient subgroup to relax their diet. However, dietary protocols guiding the adjustments of protein equivalent intake from protein substitute with BH4 treatment are lacking. We systematically reviewed protein substitute usage with long-term BH4 therapy. Electronic databases were searched for articles published between January 2000 and March 2020. Eighteen studies (306 PKU patients) were eligible. Meta-analyses demonstrated a significant increase in Phe and natural protein intakes and a significant decrease in protein equivalent intake from protein substitute with cofactor therapy. Protein substitute could be discontinued in 51% of responsive patients, but was still required in 49%, despite improvement in Phe tolerance. Normal growth was maintained, but micronutrient deficiency was observed with BH4 treatment. A systematic protocol to increase natural protein intake while reducing protein substitute dose should be followed to ensure protein and micronutrient requirements are met and sustained. We propose recommendations to guide healthcare professionals when adjusting dietary prescriptions of PKU patients on BH4. Studies investigating new therapeutic options in PKU should systematically collect data on protein substitute and natural protein intakes, as well as other nutritional factors.
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Affiliation(s)
- Fatma Ilgaz
- Department of Nutrition and Dietetics, Faculty of Health Sciences, Hacettepe University, 06100 Ankara, Turkey; (F.I.); (H.G.-Ö.)
| | - Cyril Marsaux
- Danone Nutricia Research, 3584CT Utrecht, The Netherlands;
| | - Alex Pinto
- Department of Dietetics, Birmingham Women’s and Children’s Hospital, Birmingham B4 6NH, UK; (A.P.); (A.M.)
| | - Rani Singh
- Metabolic Genetics Nutrition Program, Department of Human Genetics, Emory University, Atlanta, GA 30322, USA;
| | - Carmen Rohde
- Department of Paediatrics of the University Clinics Leipzig, University of Leipzig, 04103 Leipzig, Germany;
| | - Erdem Karabulut
- Department of Biostatistics, Faculty of Medicine, Hacettepe University, 06100 Ankara, Turkey;
| | - Hülya Gökmen-Özel
- Department of Nutrition and Dietetics, Faculty of Health Sciences, Hacettepe University, 06100 Ankara, Turkey; (F.I.); (H.G.-Ö.)
| | - Mirjam Kuhn
- Danone Nutricia Research, 3584CT Utrecht, The Netherlands;
| | - Anita MacDonald
- Department of Dietetics, Birmingham Women’s and Children’s Hospital, Birmingham B4 6NH, UK; (A.P.); (A.M.)
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Odagiri S, Kabata D, Tomita S, Kudo S, Sakaguchi T, Nakano N, Yamamoto K, Shintaku H, Hamazaki T. Clinical and Genetic Characteristics of Patients with Mild Hyperphenylalaninemia Identified by Newborn Screening Program in Japan. Int J Neonatal Screen 2021; 7:ijns7010017. [PMID: 33803550 PMCID: PMC8006226 DOI: 10.3390/ijns7010017] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 03/13/2021] [Accepted: 03/15/2021] [Indexed: 11/22/2022] Open
Abstract
Phenylketonuria (PKU) and hyperphenylalaninemia (HPA), both identified in newborn screening, are attributable to variants in PAH. Reportedly, the p.R53H(c.158G>A) variant is common in patients with HPA in East Asia. Here, we aimed to define the association between p.R53H and HPA phenotype, and study the long-term outcome of patients with HPA carrying p.R53H. We retrospectively reviewed the genotype in 370 patients detected by newborn screening, and identified the phenotype in 280 (117, HPA; 163, PKU). p.R413P(c.1238G>C) was the most frequently found (n = 117, 31.6%) variant, followed by p.R53H (n = 89, 24.1%). The odds ratio for heterozygous p.R53H to cause HPA was 48.3 (95% CI 19.410-120.004). Furthermore, we assessed the non-linear association between the phenylalanine (Phe) value and elapsed time using the follow-up data of the blood Phe levels of 73 patients with HPA carrying p.R53H. The predicted levels peaked at 161.9 μmol (95% CI 152.088-172.343) at 50-60 months of age and did not exceed 360 μmol/L during the 210-month long observation period. The findings suggest that patients with HPA, carrying p.R53H, do not need frequent Phe monitoring as against those with PKU. Our study provides convincing evidence to determine clinical management of patients detected through newborn screening in Japan.
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Affiliation(s)
- Shino Odagiri
- Department of Pediatrics, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan; (S.O.); (S.K.); (T.S.); (N.N.)
| | - Daijiro Kabata
- Department of Medical Statistics, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan; (D.K.); (S.T.)
| | - Shogo Tomita
- Department of Medical Statistics, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan; (D.K.); (S.T.)
| | - Satoshi Kudo
- Department of Pediatrics, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan; (S.O.); (S.K.); (T.S.); (N.N.)
| | - Tomoko Sakaguchi
- Department of Pediatrics, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan; (S.O.); (S.K.); (T.S.); (N.N.)
| | - Noriko Nakano
- Department of Pediatrics, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan; (S.O.); (S.K.); (T.S.); (N.N.)
| | - Kouji Yamamoto
- Department of Biostatistics, Yokohama City University School of Medicine, Yokohama 236-0004, Japan;
| | - Haruo Shintaku
- Donated Course “Disability Medicine and Regenerative Medicine”, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan;
| | - Takashi Hamazaki
- Department of Pediatrics, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan; (S.O.); (S.K.); (T.S.); (N.N.)
- Correspondence: ; Tel.: +81-6-6645-3815
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131
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Molecular characterization of Thai patients with phenylalanine hydroxylase deficiency and in vitro functional study of two novel PAH variants. Mol Biol Rep 2021; 48:2063-2070. [PMID: 33677757 DOI: 10.1007/s11033-021-06163-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 01/15/2021] [Indexed: 10/22/2022]
Abstract
Phenylketonuria (PKU) is an autosomal recessive amino acid metabolism disorder caused by variants in the gene encoding phenylalanine hydroxylase (PAH; EC1.14.16.1). This study aimed to assess the specific heterogeneity of PAH variants found in Thai population as well as evaluate enzyme activity and expression of novel variants. PAH gene from 13 patients was analyzed by PCR amplification and direct Sanger-sequencing of 13 exons of the coding region. The novel variants were transiently transfected in COS-7 cells for functional verification. Eleven different PAH variants were identified: all pathogenic variants were missense variants, of which the most frequent variant was p.R169L, accounting for 24% (6/25) of all identified alleles. Two novel variants p.R169L and p.Y317N and previously reported variants with mutated residues at the same positions (p.R169H and p.Y317H) were expressed in COS-7 cells. These showed mildly impaired residual activity levels (42.3-63.1% of wild type), while the protein levels were well expressed (82.8-110%), except for p.R169L, which showed decreased protein expression of 55.7% compared to the wild type enzyme. All subjects with p.R169L identified in at least one of pathogenic alleles (one case is homozygous) had a metabolic phenotype of mild hyperphenylalaninemia (HPA). Our data has expanded the information on the genetic heterogeneity of Thai patients with PAH deficiency. This finding emphasizes the importance of genotyping in patients with HPA, and in vitro studies can provide additional information for prediction of phenotype.
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Newbould E, Pinto A, Evans S, Ford S, O’Driscoll M, Ashmore C, Daly A, MacDonald A. Accidental Consumption of Aspartame in Phenylketonuria: Patient Experiences. Nutrients 2021; 13:nu13020707. [PMID: 33672234 PMCID: PMC7926728 DOI: 10.3390/nu13020707] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/18/2021] [Accepted: 02/19/2021] [Indexed: 12/04/2022] Open
Abstract
Aspartame is a phenylalanine containing sweetener, added to foods and drinks, which is avoided in phenylketonuria (PKU). However, the amount of phenylalanine provided by aspartame is unidentifiable from food and drinks labels. We performed a cross-sectional online survey aiming to examine the accidental aspartame consumption in PKU. 206 questionnaires (58% female) were completed. 55% of respondents (n = 114) were adults with PKU or their parent/carers and 45% (n = 92) were parents/carers of children with PKU. 74% (n = 152/206) had consumed food/drinks containing aspartame. Repeated accidental aspartame consumption was common and more frequent in children (p < 0.0001). The aspartame containing food/drinks accidentally consumed were fizzy drinks (68%, n = 103/152), fruit squash (40%, n = 61/152), chewing gum (30%, n = 46/152), flavoured water (25%, n = 38/152), ready to drink fruit squash cartons (23%, n = 35/152) and sports drinks (21%, n = 32/152). The main reasons described for accidental consumption, were manufacturers’ changing recipes (81%, n = 123/152), inability to check the ingredients in pubs/restaurants/vending machines (59%, n = 89/152) or forgetting to check the label (32%, n = 49/152). 23% (n= 48/206) had been prescribed medicines containing aspartame and 75% (n = 36/48) said that medicines were not checked by medics when prescribed. 85% (n = 164/192) considered the sugar tax made accidental aspartame consumption more likely. Some of the difficulties for patients were aspartame identification in drinks consumed in restaurants, pubs, vending machines (77%, n = 158/206); similarities in appearance of aspartame and non-aspartame products (62%, n = 127/206); time consuming shopping/checking labels (56%, n = 115/206); and unclear labelling (55%, n = 114/206). These issues caused anxiety for the person with PKU (52%, n = 106/206), anxiety for parent/caregivers (46%, n = 95/206), guilt for parent/carers (42%, n = 87/206) and social isolation (42%, n = 87/206). It is important to understand the impact of aspartame and legislation such as the sugar tax on people with PKU. Policy makers and industry should ensure that the quality of life of people with rare conditions such as PKU is not compromised through their action.
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Affiliation(s)
- Ella Newbould
- Faculty of Health, Education & Life Sciences, Birmingham City University: City South Campus, Westbourne Road, Edgbaston, Birmingham B15 3TN, UK;
| | - Alex Pinto
- Birmingham Women’s and Children’s NHS Foundation Trust, Steelhouse Lane, Birmingham B4 6NH, UK; (A.P.); (S.E.); (C.A.); (A.D.)
| | - Sharon Evans
- Birmingham Women’s and Children’s NHS Foundation Trust, Steelhouse Lane, Birmingham B4 6NH, UK; (A.P.); (S.E.); (C.A.); (A.D.)
| | - Suzanne Ford
- National Society for Phenylketonuria, Purley CR8 9DD, UK;
| | - Mike O’Driscoll
- School of Health and Education, Middlesex University, Room WG41A (Williams Building), The Burroughs Hendon, London NW4 4BT, UK;
| | - Catherine Ashmore
- Birmingham Women’s and Children’s NHS Foundation Trust, Steelhouse Lane, Birmingham B4 6NH, UK; (A.P.); (S.E.); (C.A.); (A.D.)
| | - Anne Daly
- Birmingham Women’s and Children’s NHS Foundation Trust, Steelhouse Lane, Birmingham B4 6NH, UK; (A.P.); (S.E.); (C.A.); (A.D.)
| | - Anita MacDonald
- Birmingham Women’s and Children’s NHS Foundation Trust, Steelhouse Lane, Birmingham B4 6NH, UK; (A.P.); (S.E.); (C.A.); (A.D.)
- Correspondence:
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133
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Phenylketonuria Diagnosis by Massive Parallel Sequencing and Genotype-Phenotype Association in Brazilian Patients. Genes (Basel) 2020; 12:genes12010020. [PMID: 33375644 PMCID: PMC7824641 DOI: 10.3390/genes12010020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 12/21/2020] [Accepted: 12/22/2020] [Indexed: 12/04/2022] Open
Abstract
Phenylketonuria (PKU) is a common inborn error of amino acid metabolism in which the enzyme phenylalanine hydroxylase, which converts phenylalanine to tyrosine, is functionally impaired due to pathogenic variants in the PAH gene. Thirty-four Brazilian patients with a biochemical diagnosis of PKU, from 33 unrelated families, were analyzed through next-generation sequencing in the Ion Torrent PGM™ platform. Phenotype–genotype correlations were made based on the BioPKU database. Three patients required additional Sanger sequencing analyses. Twenty-six different pathogenic variants were identified. The most frequent variants were c.1315+1G>A (n = 8/66), c.473G>A (n = 6/66), and c.1162G>A (n = 6/66). One novel variant, c.524C>G (p.Pro175Arg), was found in one allele and was predicted as likely pathogenic by the American College of Medical Genetics and Genomics (ACMG) criteria. The molecular modeling of p.Pro175Arg indicated that this substitution can affect monomers binding in the PAH tetramer, which could lead to a change in the stability and activity of this enzyme. Next-generation sequencing was a fast and effective method for diagnosing PKU and is useful for patient phenotype prediction and genetic counseling.
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