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Vieira Neto E, Laranjeira F, Quelhas D, Ribeiro I, Seabra A, Mineiro N, d. M. Carvalho L, Lacerda L, G. Ribeiro M. Mutation analysis of the PAH gene in phenylketonuria patients from Rio de Janeiro, Southeast Brazil. Mol Genet Genomic Med 2018; 6:575-591. [PMID: 29749107 PMCID: PMC6081236 DOI: 10.1002/mgg3.408] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 03/29/2018] [Accepted: 04/06/2018] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Phenylketonuria (PKU) is an autosomal recessive disease resulting from mutations in the PAH gene. Most of the patients are compound heterozygotes, and genotype is a major factor in determining the phenotypic variability of PKU. More than 1,000 variants have been described in the PAH gene. Rio de Janeiro's population has a predominance of Iberian, followed by African and Amerindian ancestries. It is expected that most PKU variants in this Brazilian state have originated in the Iberian Peninsula. However, rare European, African or pathogenic variants that are characteristic of the admixed population of the state might also be found. METHODS A total of 102 patients were included in this study. Genomic DNA was isolated from dried blood spots. Sanger sequencing was used for PAH gene variant identification. Deletions and duplications were also screened using MLPA analysis. Haplotypes were also determined. RESULTS Nine (8.8%) homozygous and 93 (91.2%) compound heterozygous patients were found. The spectrum included 37 causative mutations. Missense, nonsense, and splicing pathogenic variants corresponded to 63.7%, 2.9%, and 22.6% of the mutant alleles, respectively. Large (1.5%), and small deletions, inframe (5.4%) and with frameshift (3.9%), comprised the remainder. The most frequent pathogenic variants were: p.V388M (12.7%), p.R261Q (11.8%), IVS10-11G>A (10.3%), IVS2+5G>C (6.4%), p.S349P (6.4%), p.R252W (5.4%), p.I65T (4.4%), p.T323del (4.4%), and p.P281L (3.4%). One novel variant was detected: c.934G>T (p.G312C) [rs763115697]. CONCLUSION The three most frequent pathogenic variants in our study (34.8% of the alleles) were also the most common in other Brazilian states, Portugal, and Spain (p.V388M, p.R261Q, IVS10-11G>A), corroborating that the Iberian Peninsula is the major source of PAH mutations in Rio de Janeiro. Pathogenic variants that have other geographical origins, such IVS2+5G>C, p.G352Vfs*48, and IVS12+1G>A were also detected. Genetic drift and founder effect may have also played a role in the mutation spectrum we observed.
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Affiliation(s)
- Eduardo Vieira Neto
- Gerência de Monitoramento AssistencialAgência Nacional de Saúde SuplementarRio de JaneiroBrazil
- Serviço de Genética MédicaInstituto de Puericultura e Pediatria Martagão GesteiraUniversidade Federal do Rio de JaneiroRio de JaneiroBrazil
| | - Francisco Laranjeira
- Centro de Genética Médica Doutor Jacinto MagalhãesUnidade de Bioquímica GenéticaPortoPortugal
| | - Dulce Quelhas
- Centro de Genética Médica Doutor Jacinto MagalhãesUnidade de Bioquímica GenéticaPortoPortugal
| | - Isaura Ribeiro
- Centro de Genética Médica Doutor Jacinto MagalhãesUnidade de Bioquímica GenéticaPortoPortugal
| | - Alexandre Seabra
- Centro de Genética Médica Doutor Jacinto MagalhãesUnidade de Bioquímica GenéticaPortoPortugal
| | - Nicole Mineiro
- Centro de Genética Médica Doutor Jacinto MagalhãesUnidade de Bioquímica GenéticaPortoPortugal
| | - Lilian d. M. Carvalho
- Serviço de MetabologiaInstituto de Diabetes e Endocrinologia Luiz CapriglioneRio de JaneiroBrazil
| | - Lúcia Lacerda
- Centro de Genética Médica Doutor Jacinto MagalhãesUnidade de Bioquímica GenéticaPortoPortugal
| | - Márcia G. Ribeiro
- Serviço de Genética MédicaInstituto de Puericultura e Pediatria Martagão GesteiraUniversidade Federal do Rio de JaneiroRio de JaneiroBrazil
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Danecka MK, Woidy M, Zschocke J, Feillet F, Muntau AC, Gersting SW. Mapping the functional landscape of frequent phenylalanine hydroxylase (PAH) genotypes promotes personalised medicine in phenylketonuria. J Med Genet 2015; 52:175-85. [PMID: 25596310 DOI: 10.1136/jmedgenet-2014-102621] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
BACKGROUND In phenylketonuria, genetic heterogeneity, frequent compound heterozygosity, and the lack of functional data for phenylalanine hydroxylase genotypes hamper reliable phenotype prediction and individualised treatment. METHODS A literature search revealed 690 different phenylalanine hydroxylase genotypes in 3066 phenylketonuria patients from Europe and the Middle East. We determined phenylalanine hydroxylase function of 30 frequent homozygous and compound heterozygous genotypes covering 55% of the study population, generated activity landscapes, and assessed the phenylalanine hydroxylase working range in the metabolic (phenylalanine) and therapeutic (tetrahydrobiopterin) space. RESULTS Shared patterns in genotype-specific functional landscapes were linked to biochemical and pharmacological phenotypes, where (1) residual activity below 3.5% was associated with classical phenylketonuria unresponsive to pharmacological treatment; (2) lack of defined peak activity induced loss of response to tetrahydrobiopterin; (3) a higher cofactor need was linked to inconsistent clinical phenotypes and low rates of tetrahydrobiopterin response; and (4) residual activity above 5%, a defined peak of activity, and a normal cofactor need were associated with pharmacologically treatable mild phenotypes. In addition, we provide a web application for retrieving country-specific information on genotypes and genotype-specific phenylalanine hydroxylase function that warrants continuous extension, updates, and research on demand. CONCLUSIONS The combination of genotype-specific functional analyses with biochemical, clinical, and therapeutic data of individual patients may serve as a powerful tool to enable phenotype prediction and to establish personalised medicine strategies for dietary regimens and pharmacological treatment in phenylketonuria.
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Affiliation(s)
- Marta K Danecka
- Department of Molecular Pediatrics, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany
| | - Mathias Woidy
- Department of Molecular Pediatrics, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany
| | - Johannes Zschocke
- Division of Human Genetics, Medical University Innsbruck, Innsbruck, Austria
| | - François Feillet
- Department of Pediatrics, Hôpital d'Enfants Brabois, CHU Nancy, Vandoeuvre les Nancy, France
| | - Ania C Muntau
- University Children's Hospital, University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | - Søren W Gersting
- Department of Molecular Pediatrics, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany
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Camp KM, Parisi MA, Acosta PB, Berry GT, Bilder DA, Blau N, Bodamer OA, Brosco JP, Brown CS, Burlina AB, Burton BK, Chang CS, Coates PM, Cunningham AC, Dobrowolski SF, Ferguson JH, Franklin TD, Frazier DM, Grange DK, Greene CL, Groft SC, Harding CO, Howell RR, Huntington KL, Hyatt-Knorr HD, Jevaji IP, Levy HL, Lichter-Konecki U, Lindegren ML, Lloyd-Puryear MA, Matalon K, MacDonald A, McPheeters ML, Mitchell JJ, Mofidi S, Moseley KD, Mueller CM, Mulberg AE, Nerurkar LS, Ogata BN, Pariser AR, Prasad S, Pridjian G, Rasmussen SA, Reddy UM, Rohr FJ, Singh RH, Sirrs SM, Stremer SE, Tagle DA, Thompson SM, Urv TK, Utz JR, van Spronsen F, Vockley J, Waisbren SE, Weglicki LS, White DA, Whitley CB, Wilfond BS, Yannicelli S, Young JM. Phenylketonuria Scientific Review Conference: state of the science and future research needs. Mol Genet Metab 2014; 112:87-122. [PMID: 24667081 DOI: 10.1016/j.ymgme.2014.02.013] [Citation(s) in RCA: 133] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 02/25/2014] [Accepted: 02/26/2014] [Indexed: 01/17/2023]
Abstract
New developments in the treatment and management of phenylketonuria (PKU) as well as advances in molecular testing have emerged since the National Institutes of Health 2000 PKU Consensus Statement was released. An NIH State-of-the-Science Conference was convened in 2012 to address new findings, particularly the use of the medication sapropterin to treat some individuals with PKU, and to develop a research agenda. Prior to the 2012 conference, five working groups of experts and public members met over a 1-year period. The working groups addressed the following: long-term outcomes and management across the lifespan; PKU and pregnancy; diet control and management; pharmacologic interventions; and molecular testing, new technologies, and epidemiologic considerations. In a parallel and independent activity, an Evidence-based Practice Center supported by the Agency for Healthcare Research and Quality conducted a systematic review of adjuvant treatments for PKU; its conclusions were presented at the conference. The conference included the findings of the working groups, panel discussions from industry and international perspectives, and presentations on topics such as emerging treatments for PKU, transitioning to adult care, and the U.S. Food and Drug Administration regulatory perspective. Over 85 experts participated in the conference through information gathering and/or as presenters during the conference, and they reached several important conclusions. The most serious neurological impairments in PKU are preventable with current dietary treatment approaches. However, a variety of more subtle physical, cognitive, and behavioral consequences of even well-controlled PKU are now recognized. The best outcomes in maternal PKU occur when blood phenylalanine (Phe) concentrations are maintained between 120 and 360 μmol/L before and during pregnancy. The dietary management treatment goal for individuals with PKU is a blood Phe concentration between 120 and 360 μmol/L. The use of genotype information in the newborn period may yield valuable insights about the severity of the condition for infants diagnosed before maximal Phe levels are achieved. While emerging and established genotype-phenotype correlations may transform our understanding of PKU, establishing correlations with intellectual outcomes is more challenging. Regarding the use of sapropterin in PKU, there are significant gaps in predicting response to treatment; at least half of those with PKU will have either minimal or no response. A coordinated approach to PKU treatment improves long-term outcomes for those with PKU and facilitates the conduct of research to improve diagnosis and treatment. New drugs that are safe, efficacious, and impact a larger proportion of individuals with PKU are needed. However, it is imperative that treatment guidelines and the decision processes for determining access to treatments be tied to a solid evidence base with rigorous standards for robust and consistent data collection. The process that preceded the PKU State-of-the-Science Conference, the conference itself, and the identification of a research agenda have facilitated the development of clinical practice guidelines by professional organizations and serve as a model for other inborn errors of metabolism.
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Affiliation(s)
- Kathryn M Camp
- Office of Dietary Supplements, National Institutes of Health, Bethesda, MD 20982, USA.
| | - Melissa A Parisi
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
| | | | - Gerard T Berry
- Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
| | - Deborah A Bilder
- Department of Psychiatry, University of Utah, Salt Lake City, UT 84108, USA.
| | - Nenad Blau
- University Children's Hospital, Heidelberg, Germany; University Children's Hospital, Zürich, Switzerland.
| | - Olaf A Bodamer
- University of Miami Miller School of Medicine, Miami, FL 33136, USA.
| | - Jeffrey P Brosco
- University of Miami Mailman Center for Child Development, Miami, FL 33101, USA.
| | | | | | - Barbara K Burton
- Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, IL 60611, USA.
| | - Christine S Chang
- Agency for Healthcare Research and Quality, Rockville, MD 20850, USA.
| | - Paul M Coates
- Office of Dietary Supplements, National Institutes of Health, Bethesda, MD 20982, USA.
| | - Amy C Cunningham
- Tulane University Medical School, Hayward Genetics Center, New Orleans, LA 70112, USA.
| | | | - John H Ferguson
- Office of Rare Diseases Research, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20982, USA.
| | | | | | - Dorothy K Grange
- Washington University School of Medicine, St. Louis Children's Hospital, St. Louis, MO 63110, USA.
| | - Carol L Greene
- University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | - Stephen C Groft
- Office of Rare Diseases Research, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20982, USA.
| | - Cary O Harding
- Oregon Health & Science University, Portland, OR 97239, USA.
| | - R Rodney Howell
- University of Miami Miller School of Medicine, Miami, FL 33136, USA.
| | | | - Henrietta D Hyatt-Knorr
- Office of Rare Diseases Research, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20982, USA.
| | - Indira P Jevaji
- Office of Research on Women's Health, National Institutes of Health, Bethesda, MD 20817, USA.
| | - Harvey L Levy
- Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
| | - Uta Lichter-Konecki
- George Washington University, Children's National Medical Center, Washington, DC 20010, USA.
| | | | | | | | | | - Melissa L McPheeters
- Vanderbilt Evidence-based Practice Center, Institute for Medicine and Public Health, Nashville, TN 37203, USA.
| | - John J Mitchell
- McGill University Health Center, Montreal, Quebec H3H 1P3, Canada.
| | - Shideh Mofidi
- Maria Fareri Children's Hospital of Westchester Medical Center, Valhalla, NY 10595, USA.
| | - Kathryn D Moseley
- University of Southern California Keck School of Medicine, Los Angeles, CA 90033, USA.
| | - Christine M Mueller
- Office of Orphan Products Development, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA.
| | - Andrew E Mulberg
- Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA.
| | - Lata S Nerurkar
- Office of Rare Diseases Research, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20982, USA.
| | - Beth N Ogata
- University of Washington, Seattle, WA 98195, USA.
| | - Anne R Pariser
- Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA.
| | - Suyash Prasad
- BioMarin Pharmaceutical Inc., San Rafael, CA 94901, USA.
| | - Gabriella Pridjian
- Tulane University Medical School, Hayward Genetics Center, New Orleans, LA 70112, USA.
| | | | - Uma M Reddy
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
| | | | | | - Sandra M Sirrs
- Vancouver General Hospital, University of British Columbia, Vancouver V5Z 1M9, Canada.
| | | | - Danilo A Tagle
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Susan M Thompson
- The Children's Hospital at Westmead, Sydney, NSW 2145, Australia.
| | - Tiina K Urv
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Jeanine R Utz
- University of Minnesota, Minneapolis, MN 55455, USA.
| | - Francjan van Spronsen
- University of Groningen, University Medical Center of Groningen, Beatrix Children's Hospital, Netherlands.
| | - Jerry Vockley
- University of Pittsburgh, Pittsburgh, PA 15224, USA.
| | - Susan E Waisbren
- Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
| | - Linda S Weglicki
- National Institute of Nursing Research, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Desirée A White
- Department of Psychology, Washington University, St. Louis, MO 63130, USA.
| | | | - Benjamin S Wilfond
- Seattle Children's Research Institute, University of Washington School of Medicine, Seattle, WA 98101, USA.
| | | | - Justin M Young
- The Young Face, Facial Plastic and Reconstructive Surgery, Cumming, GA 30041, USA.
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