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Iverson R, Taljaard M, Geraghty MT, Pugliese M, Tingley K, Coyle D, Kronick JB, Wilson K, Austin V, Brunel-Guitton C, Buhas D, Butcher NJ, Chan AKJ, Dyack S, Goobie S, Greenberg CR, Jain-Ghai S, Inbar-Feigenberg M, Karp N, Kozenko M, Langley E, Lines M, Little J, MacKenzie J, Maranda B, Mercimek-Andrews S, Mhanni A, Mitchell JJ, Nagy L, Offringa M, Pender A, Potter M, Prasad C, Ratko S, Salvarinova R, Schulze A, Siriwardena K, Sondheimer N, Sparkes R, Stockler-Ipsiroglu S, Tapscott K, Trakadis Y, Turner L, Van Karnebeek C, Vandersteen A, Walia JS, Wilson BJ, Yu AC, Potter BK, Chakraborty P. Assessing the quality and value of metabolic chart data for capturing core outcomes for pediatric medium-chain acyl-CoA dehydrogenase (MCAD) deficiency. BMC Pediatr 2024; 24:37. [PMID: 38216926 PMCID: PMC10787451 DOI: 10.1186/s12887-023-04393-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 10/27/2023] [Indexed: 01/14/2024] Open
Abstract
BACKGROUND Generating rigorous evidence to inform care for rare diseases requires reliable, sustainable, and longitudinal measurement of priority outcomes. Having developed a core outcome set for pediatric medium-chain acyl-CoA dehydrogenase (MCAD) deficiency, we aimed to assess the feasibility of prospective measurement of these core outcomes during routine metabolic clinic visits. METHODS We used existing cohort data abstracted from charts of 124 children diagnosed with MCAD deficiency who participated in a Canadian study which collected data from birth to a maximum of 11 years of age to investigate the frequency of clinic visits and quality of metabolic chart data for selected outcomes. We recorded all opportunities to collect outcomes from the medical chart as a function of visit rate to the metabolic clinic, by treatment centre and by child age. We applied a data quality framework to evaluate data based on completeness, conformance, and plausibility for four core MCAD outcomes: emergency department use, fasting time, metabolic decompensation, and death. RESULTS The frequency of metabolic clinic visits decreased with increasing age, from a rate of 2.8 visits per child per year (95% confidence interval, 2.3-3.3) among infants 2 to 6 months, to 1.0 visit per child per year (95% confidence interval, 0.9-1.2) among those ≥ 5 years of age. Rates of emergency department visits followed anticipated trends by child age. Supplemental findings suggested that some emergency visits occur outside of the metabolic care treatment centre but are not captured. Recommended fasting times were updated relatively infrequently in patients' metabolic charts. Episodes of metabolic decompensation were identifiable but required an operational definition based on acute manifestations most commonly recorded in the metabolic chart. Deaths occurred rarely in these patients and quality of mortality data was not evaluated. CONCLUSIONS Opportunities to record core outcomes at the metabolic clinic occur at least annually for children with MCAD deficiency. Methods to comprehensively capture emergency care received at outside institutions are needed. To reduce substantial heterogeneous recording of core outcome across treatment centres, improved documentation standards are required for recording of recommended fasting times and a consensus definition for metabolic decompensations needs to be developed and implemented.
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Affiliation(s)
- Ryan Iverson
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada
| | - Monica Taljaard
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Canada
| | - Michael T Geraghty
- Department of Pediatrics, Children's Hospital of Eastern Ontario and University of Ottawa, 401 Smyth Road, Ottawa, ON, K1H 8L1, Canada
| | - Michael Pugliese
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada
| | - Kylie Tingley
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada
| | - Doug Coyle
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada
| | | | - Kumanan Wilson
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Canada
- Bruyère Research Institute, Ottawa, Canada
- Department of Medicine, University of Ottawa, Ottawa, Canada
| | - Valerie Austin
- The Hospital for Sick Children/University of Toronto, Toronto, Canada
| | | | | | - Nancy J Butcher
- The Hospital for Sick Children Research Institute/University of Toronto, Toronto, Canada
| | - Alicia K J Chan
- Department of Medical Genetics, University of Alberta/Stollery Children's Hospital, Edmonton, Canada
| | - Sarah Dyack
- IWK Health Centre/Dalhousie University, Halifax, Canada
| | - Sharan Goobie
- IWK Health Centre/Dalhousie University, Halifax, Canada
| | - Cheryl R Greenberg
- Health Sciences Centre Winnipeg/University of Manitoba, Winnipeg, Canada
| | - Shailly Jain-Ghai
- Department of Medical Genetics, University of Alberta/Stollery Children's Hospital, Edmonton, Canada
| | | | - Natalya Karp
- London Health Sciences Centre/Western University, London, Canada
| | | | - Erica Langley
- Department of Pediatrics, Children's Hospital of Eastern Ontario and University of Ottawa, 401 Smyth Road, Ottawa, ON, K1H 8L1, Canada
| | - Matthew Lines
- Hamilton Health Sciences Centre/McMaster University, Hamilton, Canada
| | - Julian Little
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada
| | - Jennifer MacKenzie
- McMaster Children's Hospital, Hamilton, Canada
- Janeway Children's Hospital/Memorial University, St John's, Canada
| | - Bruno Maranda
- CIUSSSE-CHUS, Université de Sherbrooke, Sherbrooke, Canada, Sherbrooke, Canada
| | | | - Aizeddin Mhanni
- Health Sciences Centre Winnipeg/University of Manitoba, Winnipeg, Canada
| | | | - Laura Nagy
- The Hospital for Sick Children/University of Toronto, Toronto, Canada
| | - Martin Offringa
- The Hospital for Sick Children Research Institute/University of Toronto, Toronto, Canada
| | - Amy Pender
- McMaster Children's Hospital, Hamilton, Canada
| | | | - Chitra Prasad
- London Health Sciences Centre/Western University, London, Canada
| | - Suzanne Ratko
- London Health Sciences Centre/Western University, London, Canada
| | - Ramona Salvarinova
- BC Children's Hospital/University of British Columbia, Vancouver, Canada
| | - Andreas Schulze
- The Hospital for Sick Children/University of Toronto, Toronto, Canada
| | - Komudi Siriwardena
- Department of Medical Genetics, University of Alberta/Stollery Children's Hospital, Edmonton, Canada
| | - Neal Sondheimer
- The Hospital for Sick Children/University of Toronto, Toronto, Canada
| | - Rebecca Sparkes
- Alberta Children's Hospital/University of Calgary, Calgary, Canada
| | | | - Kendra Tapscott
- BC Children's Hospital/University of British Columbia, Vancouver, Canada
| | | | - Lesley Turner
- Janeway Children's Hospital/Memorial University, St John's, Canada
| | - Clara Van Karnebeek
- BC Children's Hospital/University of British Columbia, Vancouver, Canada
- Emma Center for Personalized Medicine, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | | | - Jagdeep S Walia
- Kingston Health Sciences/Queen's University, Kingston, Canada
| | - Brenda J Wilson
- Janeway Children's Hospital/Memorial University, St John's, Canada
| | - Andrea C Yu
- Department of Pediatrics, Children's Hospital of Eastern Ontario and University of Ottawa, 401 Smyth Road, Ottawa, ON, K1H 8L1, Canada
| | - Beth K Potter
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada
| | - Pranesh Chakraborty
- Department of Pediatrics, Children's Hospital of Eastern Ontario and University of Ottawa, 401 Smyth Road, Ottawa, ON, K1H 8L1, Canada.
- Newborn Screening Ontario, Ottawa, Canada.
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2
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Holm LL, Doktor TK, Hansen MB, Petersen USS, Andresen BS. Vulnerable exons, like ACADM exon 5, are highly dependent on maintaining a correct balance between splicing enhancers and silencers. Hum Mutat 2021; 43:253-265. [PMID: 34923709 DOI: 10.1002/humu.24321] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Revised: 11/08/2021] [Accepted: 12/15/2021] [Indexed: 12/22/2022]
Abstract
It is now widely accepted that aberrant splicing of constitutive exons is often caused by mutations affecting cis-acting splicing regulatory elements, but there is a misconception that all exons have an equal dependency on splicing regulatory elements and thus a similar susceptibility to aberrant splicing. We investigated exonic mutations in ACADM exon 5 to experimentally examine their effect on splicing and found that 7 out of 11 tested mutations affected exon inclusion, demonstrating that this constitutive exon is particularly vulnerable to exonic splicing mutations. Employing ACADM exon 5 and 6 as models, we demonstrate that the balance between splicing enhancers and silencers, flanking intron length, and flanking splice site strength are important factors that determine exon definition and splicing efficiency of the exon in question. Our study shows that two constitutive exons in ACADM have different inherent vulnerabilities to exonic splicing mutations. This suggests that in silico prediction of potential pathogenic effects on splicing from exonic mutations may be improved by also considering the inherent vulnerability of the exon. Moreover, we show that single nucleotide polymorphism that affect either of two different exonic splicing silencers, located far apart in exon 5, all protect against both immediately flanking and more distant exonic splicing mutations.
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Affiliation(s)
- Lise L Holm
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M., Denmark.,Department of Molecular Biology and Biochemistry, The Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
| | - Thomas K Doktor
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M., Denmark.,Department of Molecular Biology and Biochemistry, The Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
| | - Michael B Hansen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M., Denmark.,Department of Molecular Biology and Biochemistry, The Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
| | - Ulrika S S Petersen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M., Denmark.,Department of Molecular Biology and Biochemistry, The Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
| | - Brage S Andresen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M., Denmark.,Department of Molecular Biology and Biochemistry, The Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
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3
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Sinclair GB, Ester M, Horvath G, Karnebeek CDV, Stockler-Ipsirogu S, Vallance H. Integrated Multianalyte Second-Tier Testing for Newborn Screening for MSUD, IVA, and GAMT Deficiencies. JOURNAL OF INBORN ERRORS OF METABOLISM AND SCREENING 2016. [DOI: 10.1177/2326409816666296] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Graham B. Sinclair
- Department of Pathology and Laboratory Medicine, British Columbia Children’s Hospital, Vancouver, BC, Canada
- Treatable Intellectual Disability Endeavour, British Columbia Children’s Hospital, Vancouver, BC, Canada
- Child and Family Research Institute, British Columbia Children’s Hospital, Vancouver, BC, Canada
- University of British Columbia, British Columbia Children’s Hospital, Vancouver, BC, Canada
| | - Manuel Ester
- Department of Pathology and Laboratory Medicine, British Columbia Children’s Hospital, Vancouver, BC, Canada
| | - Gabriella Horvath
- University of British Columbia, British Columbia Children’s Hospital, Vancouver, BC, Canada
- Department of Pediatrics, British Columbia Children’s Hospital, Vancouver, BC, Canada
- Centre for Molecular Medicine and Therapeutics, British Columbia Children’s Hospital, Vancouver, BC, Canada
| | - Clara D. van Karnebeek
- Treatable Intellectual Disability Endeavour, British Columbia Children’s Hospital, Vancouver, BC, Canada
- Child and Family Research Institute, British Columbia Children’s Hospital, Vancouver, BC, Canada
- University of British Columbia, British Columbia Children’s Hospital, Vancouver, BC, Canada
- Department of Pediatrics, British Columbia Children’s Hospital, Vancouver, BC, Canada
- Centre for Molecular Medicine and Therapeutics, British Columbia Children’s Hospital, Vancouver, BC, Canada
| | - Sylvia Stockler-Ipsirogu
- Treatable Intellectual Disability Endeavour, British Columbia Children’s Hospital, Vancouver, BC, Canada
- Child and Family Research Institute, British Columbia Children’s Hospital, Vancouver, BC, Canada
- University of British Columbia, British Columbia Children’s Hospital, Vancouver, BC, Canada
- Department of Pediatrics, British Columbia Children’s Hospital, Vancouver, BC, Canada
| | - Hilary Vallance
- Department of Pathology and Laboratory Medicine, British Columbia Children’s Hospital, Vancouver, BC, Canada
- Treatable Intellectual Disability Endeavour, British Columbia Children’s Hospital, Vancouver, BC, Canada
- Child and Family Research Institute, British Columbia Children’s Hospital, Vancouver, BC, Canada
- University of British Columbia, British Columbia Children’s Hospital, Vancouver, BC, Canada
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4
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Mercimek-Mahmutoglu S, Sinclair G, van Dooren SJM, Kanhai W, Ashcraft P, Michel OJ, Nelson J, Betsalel OT, Sweetman L, Jakobs C, Salomons GS. Guanidinoacetate methyltransferase deficiency: first steps to newborn screening for a treatable neurometabolic disease. Mol Genet Metab 2012; 107:433-7. [PMID: 23031365 DOI: 10.1016/j.ymgme.2012.07.022] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 07/27/2012] [Indexed: 01/10/2023]
Abstract
BACKGROUND GAMT deficiency is an autosomal recessive disorder of creatine biosynthesis resulting in severe neurological complications in untreated patients. Currently available treatment is only successful to stop disease progression, but is not sufficient to reverse neurological complications occurring prior to diagnosis. Normal neurodevelopmental outcome in a patient, treated in the newborn period, highlights the importance of early diagnosis. METHODS Targeted mutation analysis (c.59G>C and c.327G>A) in the GAMT gene by the QIAxcel system and GAA measurement by a novel two-tier method were performed in 3000 anonymized newborn blood dot spot cards. RESULTS None of the targeted mutations were detected in any newborn. Two novel heterozygous variants (c.283_285dupGTC; p.Val95dup and c.278_283delinsCTCGATGCAC; p.Asp93AlafsX35) were identified by coincidence. Carrier frequency for these insertion/deletion types of GAMT mutations was 1/1475 in this small cohort of newborns. GAA levels were at or above the 99th percentile (3.12 μmol/l) in 4 newborns. Second-tier testing showed normal results for 4 newborns revealing 0.1% false positive rate. No GAMT mutations were identified in 4 of the newborns with elevated GAA levels in the first tier testing. CONCLUSION This is the first two-tier study to investigate carrier frequency of GAMT deficiency in the small cohort of newborn population to establish evidence base for the first steps toward newborn screening for this treatable neurometabolic disorder.
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Affiliation(s)
- S Mercimek-Mahmutoglu
- Division of Clinical and Metabolic Genetics, Department of Pediatrics, University of Toronto, Toronto, ON, Canada.
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5
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Sinclair GB, Collins S, Popescu O, McFadden D, Arbour L, Vallance HD. Carnitine palmitoyltransferase I and sudden unexpected infant death in British Columbia First Nations. Pediatrics 2012; 130:e1162-9. [PMID: 23090344 DOI: 10.1542/peds.2011-2924] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE Infant mortality in British Columbia (BC) First Nations remains elevated relative to other residents. The p.P479L (c.1436C>T) variant of carnitine palmitoyltransferase 1 (CPT1A) is frequent in some aboriginal populations and may be associated with increased infant deaths. This work was initiated to determine the performance of acylcarnitine profiling for detecting this variant, to determine its frequency in BC, and to determine if it is associated with sudden infant deaths in this population. METHODS Newborn screening cards from all BC First Nations infants in 2004 and all sudden unexpected deaths in BC First Nations infants (1999-2009) were genotyped for the CPT1A p.P479L variant and linked to archival acylcarnitine data. RESULTS The CPT1A p.P479L variant is frequent in BC First Nations but is not evenly distributed, with higher rates in coastal regions (up to 25% homozygosity) with historically increased infant mortality. There is also an overrepresentation of p.P479L homozygotes in unexpected infant deaths from these regions, with an odds ratio of 3.92 (95% confidence interval: 1.69-9.00). Acylcarnitine profiling will identify p.P479L homozygotes with a 94% sensitivity and specificity. CONCLUSIONS The CPT1A p.P479L variant is common to some coastal BC First Nations, and homozygosity for this variant is associated with unexpected death in infancy. The high frequency of this variant in a wide range of coastal aboriginal communities, however, suggests a selective advantage, raising the possibility that this variant may have differing impacts on health depending on the environmental or developmental context.
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Affiliation(s)
- Graham B Sinclair
- Departmens of aPathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia.
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6
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Characterization of the molecular spectrum of Medium-Chain Acyl-CoA Dehydrogenase Deficiency in a Greek newborns cohort: Identification of a novel variant. Clin Biochem 2012; 45:1167-72. [DOI: 10.1016/j.clinbiochem.2012.05.030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Revised: 05/26/2012] [Accepted: 05/28/2012] [Indexed: 12/30/2022]
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7
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Purevsuren J, Hasegawa Y, Fukuda S, Kobayashi H, Mushimoto Y, Yamada K, Takahashi T, Fukao T, Yamaguchi S. Clinical and molecular aspects of Japanese children with medium chain acyl-CoA dehydrogenase deficiency. Mol Genet Metab 2012; 107:237-40. [PMID: 22796001 DOI: 10.1016/j.ymgme.2012.06.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 06/18/2012] [Indexed: 11/23/2022]
Abstract
We report the outcome of 16 Japanese patients with medium chain acyl-CoA dehydrogenase deficiency. Of them, 7 patients were diagnosed after metabolic crisis, while 9 were detected in the asymptomatic condition. Of the 7 symptomatic cases, 1 died suddenly, and 4 cases had delayed development. All 9 patients identified by neonatal or sibling screening remained healthy. Of 14 mutations identified, 10 were unique for Japanese, and 4 were previously reported in other nationalities. Presymptomatic detection including neonatal screening obviously improves quality of life of Japanese patients, probably regardless of the genotypes.
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Affiliation(s)
- Jamiyan Purevsuren
- Department of Pediatrics, Shimane University Faculty of Medicine, Izumo 693-8501, Japan.
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8
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Hamers FF, Rumeau-Pichon C. Cost-effectiveness analysis of universal newborn screening for medium chain acyl-CoA dehydrogenase deficiency in France. BMC Pediatr 2012; 12:60. [PMID: 22681855 PMCID: PMC3464722 DOI: 10.1186/1471-2431-12-60] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 06/08/2012] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Five diseases are currently screened on dried blood spots in France through the national newborn screening programme. Tandem mass spectrometry (MS/MS) is a technology that is increasingly used to screen newborns for an increasing number of hereditary metabolic diseases. Medium chain acyl-CoA dehydrogenase deficiency (MCADD) is among these diseases. We sought to evaluate the cost-effectiveness of introducing MCADD screening in France. METHODS We developed a decision model to evaluate, from a societal perspective and a lifetime horizon, the cost-effectiveness of expanding the French newborn screening programme to include MCADD. Published and, where available, routine data sources were used. Both costs and health consequences were discounted at an annual rate of 4%. The model was applied to a French birth cohort. One-way sensitivity analyses and worst-case scenario simulation were performed. RESULTS We estimate that MCADD newborn screening in France would prevent each year five deaths and the occurrence of neurological sequelae in two children under 5 years, resulting in a gain of 128 life years or 138 quality-adjusted life years (QALY). The incremental cost per year is estimated at €2.5 million, down to €1 million if this expansion is combined with a replacement of the technology currently used for phenylketonuria screening by MS/MS. The resulting incremental cost-effectiveness ratio (ICER) is estimated at €7 580/QALY. Sensitivity analyses indicate that while the results are robust to variations in the parameters, the model is most sensitive to the cost of neurological sequelae, MCADD prevalence, screening effectiveness and screening test cost. The worst-case scenario suggests an ICER of €72 000/QALY gained. CONCLUSIONS Although France has not defined any threshold for judging whether the implementation of a health intervention is an efficient allocation of public resources, we conclude that the expansion of the French newborn screening programme to MCADD would appear to be cost-effective. The results of this analysis have been used to produce recommendations for the introduction of universal newborn screening for MCADD in France.
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Affiliation(s)
- Françoise F Hamers
- Department of Economic and Public Health Evaluation, Haute Autorité de Santé (HAS), 2 avenue du Stade de France, Saint-Denis, France
| | - Catherine Rumeau-Pichon
- Department of Economic and Public Health Evaluation, Haute Autorité de Santé (HAS), 2 avenue du Stade de France, Saint-Denis, France
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9
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Andresen BS, Lund AM, Hougaard DM, Christensen E, Gahrn B, Christensen M, Bross P, Vested A, Simonsen H, Skogstrand K, Olpin S, Brandt NJ, Skovby F, Nørgaard-Pedersen B, Gregersen N. MCAD deficiency in Denmark. Mol Genet Metab 2012; 106:175-88. [PMID: 22542437 DOI: 10.1016/j.ymgme.2012.03.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 03/24/2012] [Accepted: 03/24/2012] [Indexed: 11/18/2022]
Abstract
Medium-chain acyl-CoA dehydrogenase deficiency (MCADD) is the most common defect of fatty acid oxidation. Many countries have introduced newborn screening for MCADD, because characteristic acylcarnitines can easily be identified in filter paper blood spot samples by tandem mass spectrometry (MS/MS), because MCADD is a frequent disease, and because of the success of early treatment initiated before clinical symptoms have emerged. In Denmark we have screened 519,350 newborns for MCADD by MS/MS and identified 58 affected babies. The diagnosis of MCADD was confirmed in all 58 newborns by mutation analysis. This gives an incidence of MCADD detected by newborn screening in Denmark of 1/8954. In sharp contrast to this we found that the incidence of clinically presenting MCADD in Denmark in the 10 year period preceding introduction of MS/MS-based screening was only 1 in 39,691. This means that four times more newborns with MCADD are detected by screening than what is expected based on the number of children presenting clinically in an unscreened population. The mutation spectrum in the newborns detected by screening is different from that observed in clinically presenting patients with a much lower proportion of newborns being homozygous for the prevalent disease-causing c.985A>G mutation. A significant number of the newborns have genotypes with mutations that have not been observed in patients detected clinically. Some of these mutations, like c.199T>C and c.127G>A, are always associated with a milder biochemical phenotype and may cause a milder form of MCADD with a relatively low risk of disease manifestation, thereby explaining part of the discrepancy between the frequency of clinically manifested MCADD and the frequency of MCADD determined by screening. In addition, our data suggest that some of this discrepancy can be explained by a reduced penetrance of the c.985A>G mutation, with perhaps only 50% of c.985A>G homozygotes presenting with disease manifestations. Interestingly, we also report that the observed number of newborns identified by screening who are homozygous for the c.985A>G mutation is twice that predicted from the estimated carrier frequency. We therefore redetermined the carrier frequency in a new sample of 1946 blood spots using a new assay, but this only confirmed that the c.985A>G carrier frequency in Denmark is approximately 1/105. We conclude that MCADD is much more frequent than expected, has a reduced penetrance and that rapid genotyping using the initial blood spot sample is important for correct diagnosis and counseling.
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Affiliation(s)
- Brage Storstein Andresen
- Research Unit for Molecular Medicine, Aarhus University Hospital and Faculty of Health Science, Skejby Sygehus, Aarhus, Denmark.
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10
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Gillingham MB, Hirschfeld M, Lowe S, Matern D, Shoemaker J, Lambert WE, Koeller DM. Impaired fasting tolerance among Alaska native children with a common carnitine palmitoyltransferase 1A sequence variant. Mol Genet Metab 2011; 104:261-4. [PMID: 21763168 PMCID: PMC3197793 DOI: 10.1016/j.ymgme.2011.06.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2011] [Revised: 06/21/2011] [Accepted: 06/22/2011] [Indexed: 11/30/2022]
Abstract
A high prevalence of the sequence variant c.1436C→T in the CPT1A gene has been identified among Alaska Native newborns but the clinical implications of this variant are unknown. We conducted medically supervised fasts in 5 children homozygous for the c.1436C→T variant. Plasma free fatty acids increased normally in these children but their long-chain acylcarnitine and ketone production was significantly blunted. The fast was terminated early in two subjects due to symptoms of hypoglycemia. Homozygosity for the c.1436C→T sequence variant of CPT1A impairs fasting ketogenesis, and can cause hypoketotic hypoglycemia in young children. Trial registration www.clinical trials.gov NCT00653666 "Metabolic Consequences of CPT1A Deficiency"
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Affiliation(s)
- Melanie B Gillingham
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR 97239, USA.
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11
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Goetzman ES. Modeling Disorders of Fatty Acid Metabolism in the Mouse. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2011; 100:389-417. [DOI: 10.1016/b978-0-12-384878-9.00010-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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12
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Kennedy S, Potter BK, Wilson K, Fisher L, Geraghty M, Milburn J, Chakraborty P. The first three years of screening for medium chain acyl-CoA dehydrogenase deficiency (MCADD) by newborn screening ontario. BMC Pediatr 2010; 10:82. [PMID: 21083904 PMCID: PMC2996355 DOI: 10.1186/1471-2431-10-82] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Accepted: 11/17/2010] [Indexed: 12/30/2022] Open
Abstract
Background Medium chain acyl-CoA dehydrogenase deficiency (MCADD) is a disorder of mitochondrial fatty acid oxidation and is one of the most common inborn errors of metabolism. Identification of MCADD via newborn screening permits the introduction of interventions that can significantly reduce associated morbidity and mortality. This study reports on the first three years of newborn screening for MCADD in Ontario, Canada. Methods Newborn Screening Ontario began screening for MCADD in April 2006, by quantification of acylcarnitines (primarily octanoylcarnitine, C8) in dried blood spots using tandem mass spectrometry. Babies with positive screening results were referred to physicians at one of five regional Newborn Screening Treatment Centres, who were responsible for diagnostic evaluation and follow-up care. Results From April 2006 through March 2009, approximately 439 000 infants were screened for MCADD in Ontario. Seventy-four infants screened positive, with a median C8 level of 0.68 uM (range 0.33-30.41 uM). Thirty-one of the screen positive infants have been confirmed to have MCADD, while 36 have been confirmed to be unaffected. Screening C8 levels were higher among infants with MCADD (median 8.93 uM) compared to those with false positive results (median 0.47 uM). Molecular testing was available for 29 confirmed cases of MCADD, 15 of whom were homozygous for the common c.985A > G mutation. Infants homozygous for the common mutation tended to have higher C8 levels (median 12.13 uM) relative to compound heterozygotes for c.985A > G and a second detectable mutation (median 2.01 uM). Eight confirmed mutation carriers were identified among infants in the false positive group. The positive predictive value of a screen positive for MCADD was 46%. The estimated birth prevalence of MCADD in Ontario is approximately 1 in 14 000. Conclusions The birth prevalence of MCADD and positive predictive value of the screening test were similar to those identified by other newborn screening programs internationally. We observed some evidence of correlation between genotype and biochemical phenotype (C8 levels), and between C8 screening levels and eventual diagnosis. Current research priorities include further examining the relationships among genotype, biochemical phenotype, and clinical phenotype, with the ultimate goal of improving clinical risk prediction in order to provide tailored disease management advice and genetic counselling to families.
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Affiliation(s)
- Shelley Kennedy
- Newborn Screening Ontario, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada
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Hoflack M, Caruba C, Pitelet G, Haas H, Mas JC, Paquis V, Berard E. [Infant coma in the emergency department: 2 cases of MCAD deficiency]. Arch Pediatr 2010; 17:1074-7. [PMID: 20434892 DOI: 10.1016/j.arcped.2010.03.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Revised: 08/06/2009] [Accepted: 03/23/2010] [Indexed: 11/26/2022]
Abstract
Medium-chain Acyl-CoA dehydrogenase deficiency (MCAD) is one of the most common fatty acid oxidation disorders. Clinical manifestations can be serious and lead to death if unrecognized. They are not specific and can mimic meningitis or an acute intestinal intussusception in its neurological form. Early recognition of MCAD and presymptomatic treatment of intercurrent illness improve the prognosis over the short- and long-term. MCAD deficiency satisfies the major criteria for newborn screening. We report the cases of 2 patients whose presentation was typical and severe. Early diagnosis of MCAD deficiency helped to start a simple treatment in both patients aimed at preventing further decompensation.
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Affiliation(s)
- M Hoflack
- Service de pédiatrie, hôpital de l'Archet II, 151 route de Saint-Antoine-de-Ginestière, Nice cedex 3, France.
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Schatz UA, Ensenauer R. The clinical manifestation of MCAD deficiency: challenges towards adulthood in the screened population. J Inherit Metab Dis 2010; 33:513-20. [PMID: 20532824 DOI: 10.1007/s10545-010-9115-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 04/17/2010] [Accepted: 04/19/2010] [Indexed: 12/30/2022]
Abstract
Medium-chain acyl-CoA dehydrogenase deficiency (MCADD) is the most common fatty acid oxidation disorder. Typically, undiagnosed individuals are asymptomatic until an episode of increased energy demand and fasting occurs, resulting in metabolic derangement. Phenotypic heterogeneity has been increasingly realized, with reports of both neonates and adults manifesting with life-threatening symptoms including encephalopathy, rhabdomyolysis, and cardiac failure. If diagnosed presymptomatically, outcome is favorable basically by avoidance of fasting. Early detection by newborn screening (NBS) has significantly reduced the incidence of severe adverse events including deaths. In this manuscript we focus on the natural course of the disease in both children and adults. Although NBS for MCADD has been successfully established, continuing efforts need to be made to avoid acute crises and deterioration of outcome in screened patients entering adolescence and adulthood.
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Affiliation(s)
- Ulrich A Schatz
- Dr. von Hauner Children's Hospital, Children's Research Center, Ludwig-Maximilians-Universität München, Munich, Germany
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Moammar H, Cheriyan G, Mathew R, Al-Sannaa N. Incidence and patterns of inborn errors of metabolism in the Eastern Province of Saudi Arabia, 1983-2008. Ann Saudi Med 2010; 30:271-7. [PMID: 20622343 PMCID: PMC2931777 DOI: 10.4103/0256-4947.65254] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND OBJECTIVES Individual inborn errors of metabolism (IEM) are rare disorders, but may not be that uncommon in our patient population. We report the incidence of IEM in a defined cohort of births at the Saudi Aramco medical facilities in the Eastern Province of Saudi Arabia over 25 years. METHODS The records of all patients diagnosed with IEM from 1 January 1983 to 31 December 2008 were reviewed and categorized according to accumulated or deficient metabolites into small-molecule disorders (aminoacidemia, organic acidopathies [OA], urea cycle defects, fatty acid oxidation, and carbohydrate metabolic disorders) and other disorders, including glycogen and lysosomal storage disorders (LSDs), and organelle disorders. RESULTS During the study period, 165,530 Saudi Arabian infants were born at Saudi Aramco and 248 were diagnosed with an IEM, corresponding to a cumulative incidence of 150 cases per 100,000 live births. Small-molecule disorders were diagnosed in 134/248 patients (54%). OA were the most common (48/248 patients; 19%), and methylmalonic aciduria was the most frequently observed OA (13/48 patients; 27%). LSDs were diagnosed in 74/248 patients (30%), and mucopolysaccharidosis was the most frequently observed LSD (28/74; 38%). CONCLUSION We believe that our data underestimate the true incidence of IEM in the region. Regional and national newborn screening programs will provide a better estimation of the incidence of IEM. We recommend a centralized newborn screening program that employs tandem mass spectrometry.
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Affiliation(s)
- Hissa Moammar
- Department of Pediatrics, King Faisal University, Dhahran, Saudi Arabia.
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17
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Ehrnhoefer DE. MCAD mutations identified in newborn screening cause different levels of enzymatic dysfunction. Clin Genet 2009; 76:146-8. [DOI: 10.1111/j.1399-0004.2009.01247_1.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Sharma S, Black SM. CARNITINE HOMEOSTASIS, MITOCHONDRIAL FUNCTION, AND CARDIOVASCULAR DISEASE. ACTA ACUST UNITED AC 2009; 6:e31-e39. [PMID: 20648231 DOI: 10.1016/j.ddmec.2009.02.001] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Carnitines are involved in mitochondrial transport of fatty acids and are of critical importance for maintaining normal mitochondrial function. This review summarizes recent experimental and clinical studies showing that mitochondrial dysfunction secondary to a disruption of carnitine homeostasis may play a role in decreased NO signaling and the development of endothelial dysfunction. Future challenges include development of agents that can positively modulate L-carnitine homeostasis which may have high therapeutic potential.
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Affiliation(s)
- Shruti Sharma
- The Pulmonary Disease Program, Vascular Biology Center, Medical College of Georgia, Augusta, GA 30912
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