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Pajares-García S, González de Aledo-Castillo JM, Flores-Jiménez JE, Collado T, Pérez J, Paredes-Fuentes AJ, Argudo-Ramírez A, López-Galera RM, Prats B, García-Villoria J. Analysis of a second-tier test panel in dried blood spot samples using liquid chromatography-tandem mass spectrometry in Catalonia's newborn screening programme. Clin Chem Lab Med 2024; 62:493-505. [PMID: 37794778 DOI: 10.1515/cclm-2023-0216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 09/21/2023] [Indexed: 10/06/2023]
Abstract
OBJECTIVES Acylcarnitine and amino acid analyses of dried blood spot (DBS) samples using tandem mass spectrometry in newborn screening (NBS) programmes can generate false positive (FP) results. Therefore, implementation of second-tier tests (2TTs) using DBS samples has become increasingly important to avoid FPs. The most widely used 2TT metabolites include methylmalonic acid, 3-hydroxypropionic acid, methylcitric acid, and homocysteine. METHODS We simultaneously measured 46 underivatised metabolites, including organic acids, acylglycine and acylcarnitine isomers, homocysteine, and orotic acid, in DBS samples using tandem mass spectrometry. To validate this method, we analysed samples from 147 healthy newborns, 160 patients with genetic disorders diagnosed via NBS, 20 patients with acquired vitamin B12 deficiency, 10 newborns receiving antibiotic treatment, and nine external quality control samples. RESULTS The validation study revealed that 31 metabolites showed good analytical performance. Furthermore, this method detected key metabolites for all diseases associated with increased levels of the following acylcarnitines: C3, C4, C5, C4DC/C5OH, and C5DC. The sensitivity of this method to detect all diseases was 100 %, and the specificity was 74-99 %, except for glutaric aciduria type 1. This method can also be used to diagnose mitochondrial fatty acid β-oxidation disorders (FAODs) and urea cycle defects (UCDs). CONCLUSIONS We have described a 2TT panel of 31 metabolites in DBS samples based on an easy and rapid method without derivatisation. Its implementation allowed us to distinguish between different organic acidurias, some FAODs, and UCDs. This new strategy has increased the efficiency of our NBS programme by reducing FP and false negative results, second sample requests, and the time required for diagnosis.
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Affiliation(s)
- Sonia Pajares-García
- Department of Biochemistry and Molecular Genetics, Section of Inborn Errors of Metabolism-IBC, Hospital Clinic, Barcelona, Spain
- Center for Biomedical Research Network on Rare Diseases (CIBERER), Madrid, Spain
| | | | - José Eduardo Flores-Jiménez
- Department of Biochemistry and Molecular Genetics, Section of Inborn Errors of Metabolism-IBC, Hospital Clinic, Barcelona, Spain
| | - Tatiana Collado
- Department of Biochemistry and Molecular Genetics, Section of Inborn Errors of Metabolism-IBC, Hospital Clinic, Barcelona, Spain
| | - Judit Pérez
- Department of Biochemistry and Molecular Genetics, Section of Inborn Errors of Metabolism-IBC, Hospital Clinic, Barcelona, Spain
| | - Abraham José Paredes-Fuentes
- Department of Biochemistry and Molecular Genetics, Section of Inborn Errors of Metabolism-IBC, Hospital Clinic, Barcelona, Spain
| | - Ana Argudo-Ramírez
- Department of Biochemistry and Molecular Genetics, Section of Inborn Errors of Metabolism-IBC, Hospital Clinic, Barcelona, Spain
| | - Rosa María López-Galera
- Department of Biochemistry and Molecular Genetics, Section of Inborn Errors of Metabolism-IBC, Hospital Clinic, Barcelona, Spain
- Center for Biomedical Research Network on Rare Diseases (CIBERER), Madrid, Spain
- Biomedical Research Institute, August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Blanca Prats
- Health Department, Maternal and Child Health Service, Public Health Agency of Catalonia, The Government of Catalonia, Barcelona, Spain
| | - Judit García-Villoria
- Department of Biochemistry and Molecular Genetics, Section of Inborn Errors of Metabolism-IBC, Hospital Clinic, Barcelona, Spain
- Center for Biomedical Research Network on Rare Diseases (CIBERER), Madrid, Spain
- Biomedical Research Institute, August Pi i Sunyer (IDIBAPS), Barcelona, Spain
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Suzuki-Yoshida K, Nakano K, Nakakuni M, Deguchi N, Mitsui S, Kobayashi S, Yamatani A, Akabane M. Research on the Clinical Practical Use of Pivoxil-Conjugated Antibodies and the Risk of Carnitine Deficiency Using Real-World Data. CHILDREN (BASEL, SWITZERLAND) 2024; 11:150. [PMID: 38397263 PMCID: PMC10887142 DOI: 10.3390/children11020150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 01/17/2024] [Accepted: 01/20/2024] [Indexed: 02/25/2024]
Abstract
In Japan, pivoxil-conjugated antibodies (PVs) are commonly used to treat infections. However, carnitine deficiency is a known adverse drug reaction associated with PV treatment. This study aimed to research the practical use of PV and assess the risk of carnitine deficiency in patients receiving PV compared to their amoxicillin (AM)-treated counterparts. The Pediatric Medical Information Collection System (P-MICS) served as the data source for this study. The study cohort comprised patients aged 0-15 years prescribed PV between April 2016 and March 2021. Data on the actual PV prescriptions were extracted for each patient. To evaluate the risk of carnitine deficiency, adverse events (AEs) were defined as carnitine deficiency and its associated symptoms. Propensity score matching was employed to compare the AE incidence between the PV and AM groups. The number of cases of PV prescriptions decreased year-on-year between 2016 and 2021, and >80% of prescriptions were dispensed in the clinic. The propensity score matching analysis demonstrated no statistically significant difference in the incidence of carnitine deficiency and its associated symptoms between the PV and AM groups. Our findings suggest that the risk of carnitine deficiency in children treated with PV is not significantly higher than that associated with other antibiotics.
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Affiliation(s)
- Kaho Suzuki-Yoshida
- Graduate School of Pharmaceutical Sciences, Meiji Pharmaceutical University, Tokyo 204-0004, Japan
- Department of Pharmacy, National Center for Child Health and Development, Tokyo 157-8535, Japan
- MSD K.K., Tokyo 102-8667, Japan
| | - Kosuke Nakano
- Clinical Research Center, National Center for Child Health and Development, Tokyo 157-8535, Japan
| | - Masayoshi Nakakuni
- Clinical Research Center, National Center for Child Health and Development, Tokyo 157-8535, Japan
| | - Naoko Deguchi
- Clinical Research Center, National Center for Child Health and Development, Tokyo 157-8535, Japan
| | - Seiji Mitsui
- Clinical Research Center, National Center for Child Health and Development, Tokyo 157-8535, Japan
| | | | - Akimasa Yamatani
- Graduate School of Pharmaceutical Sciences, Meiji Pharmaceutical University, Tokyo 204-0004, Japan
- Department of Pharmacy, National Center for Child Health and Development, Tokyo 157-8535, Japan
| | - Miki Akabane
- Graduate School of Pharmaceutical Sciences, Meiji Pharmaceutical University, Tokyo 204-0004, Japan
- Department of Pharmacy, National Center for Child Health and Development, Tokyo 157-8535, Japan
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Murko S, Aseman AD, Reinhardt F, Gramer G, Okun JG, Mütze U, Santer R. Neonatal screening for isovaleric aciduria: Reducing the increasingly high false-positive rate in Germany. JIMD Rep 2023; 64:114-120. [PMID: 36636590 PMCID: PMC9830014 DOI: 10.1002/jmd2.12345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 10/13/2022] [Accepted: 10/18/2022] [Indexed: 01/16/2023] Open
Abstract
Newborn screening (NBS) for isovaleric acidemia (IVA) is performed by flow injection tandem mass spectrometry quantifying C5 carnitines (C5). Isovalerylcarnitine, however, is isomeric with pivaloylcarnitine which can be present in blood due to maternal use of pivaloylester-containing antibiotics, available in Germany since late 2016. During a 36-month period (January 19-December 21), all newborns screened in Hamburg with a C5 above cutoff (NeoGram®: 0.50 μmol/L or Neobase®2: 0.45 μmol/L) were included in the study. As a second-tier test, a simple ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed to differentiate the C5 isomers pivaloyl-, 2-methylbutyryl-, isovaleryl-, and valerylcarnitine. Out of 156 772 newborns tested, one turned out to have genetically proven IVA while 99 were false positive (C5: 0.5-8.2 μmol/L) due to the presence of pivaloylcarnitine. These cases have increased year by year and show local clusters. Retrospective analysis of another 39 cases from 287 206 neonates tested at the NBS center in Heidelberg with C5 elevation (0.9-10.6 μmol/L) but clinical and biochemical exclusion of IVA yielded evidence of pivaloylcarnitine in all cases. Inclusion of a second-tier test into NBS significantly reduces the high and increasing false-positive rate of IVA screening. This avoids further diagnostic steps, prevents unnecessary stress and anxiety of parents in a remarkably high number of cases. If Hamburg data of 2021 are extrapolated to all of Germany, one can assume around 800 (1‰) false-positive cases in comparison to an average of two classic IVA cases per year. Unless licensing of pivaloylester-containing drugs for use during pregnancy is reconsidered, a second-tier test for C5 determination is indispensable.
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Affiliation(s)
- Simona Murko
- Newborn Screening and Metabolic Laboratory, Department of PediatricsUniversity Medical Center EppendorfHamburgGermany
| | - Asra Dadkhah Aseman
- Newborn Screening and Metabolic Laboratory, Department of PediatricsUniversity Medical Center EppendorfHamburgGermany
| | - Friederike Reinhardt
- Newborn Screening and Metabolic Laboratory, Department of PediatricsUniversity Medical Center EppendorfHamburgGermany
| | - Gwendolyn Gramer
- Newborn Screening and Metabolic Laboratory, Department of PediatricsUniversity Medical Center EppendorfHamburgGermany
| | - Jürgen Günther Okun
- Division of Child Neurology and Metabolic Medicine, Dietmar Hopp Metabolic Center, Center for Child and Adolescent Medicine HeidelbergUniversity HospitalHeidelbergGermany
| | - Ulrike Mütze
- Division of Child Neurology and Metabolic Medicine, Dietmar Hopp Metabolic Center, Center for Child and Adolescent Medicine HeidelbergUniversity HospitalHeidelbergGermany
| | - René Santer
- Newborn Screening and Metabolic Laboratory, Department of PediatricsUniversity Medical Center EppendorfHamburgGermany
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A Simple Flow Injection Analysis-Tandem Mass Spectrometry Method to Reduce False Positives of C5-Acylcarnitines Due to Pivaloylcarnitine Using Reference Ions. CHILDREN (BASEL, SWITZERLAND) 2022; 9:children9050694. [PMID: 35626871 PMCID: PMC9139860 DOI: 10.3390/children9050694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 04/12/2022] [Accepted: 05/06/2022] [Indexed: 11/21/2022]
Abstract
Flow injection analysis−tandem mass spectrometry (FIA-TMS) has been applied in a first-tier test of newborn screening (NBS). Although isovalerylcarnitine (i-C5), which is a diagnostic indicator of isovaleric acidemia (IVA), is isobaric with pivaloylcarnitine (p-C5), 2-methylbutyrylcarnitine, and n-valerylcarnitine, these isomers cannot be distinguished by the FIA-TMS. There are many reports of false positives derived from p-C5 due to the use of pivalate-conjugated antibiotics. In this study, we developed a new FIA-TMS method to distinguish i-C5 and p-C5. We found that the intensity ratio of product ions for i-C5 and p-C5 was different in a certain range even under the same analytical conditions. The product ions with the most distinct differences in ionic intensity between the isomers and the collision energies that produce them were determined to be m/z 246.2 > 187.1 and −15 V, respectively. In addition to the quantification ion, a reference ion was defined, and the similarity of the i-C5 and p-C5 reference ion ratios (i-C5 score and p-C5 score, respectively) were used to estimate which isomer (i-C5 and p-C5) was responsible for elevated C5 acylcarnitine in dried blood spots (DBSs). As a result of analyses of 11 DBS samples derived from pivalate-conjugated antibiotics and four DBS samples from IVA patients using our method, it was found that our method was able to correctly determine the type of C5-acylcarnitine (i-C5 or p-C5) in the DBS samples. Implementation of this new FIA-TMS method into the current NBS protocol will allow for a reduction in false positives in IVA.
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Development of Strategies to Decrease False Positive Results in Newborn Screening. Int J Neonatal Screen 2020; 6:ijns6040084. [PMID: 33147868 PMCID: PMC7712114 DOI: 10.3390/ijns6040084] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 10/27/2020] [Accepted: 10/31/2020] [Indexed: 01/11/2023] Open
Abstract
The expansion of national newborn screening (NBS) programmes has provided significant benefits in the diagnosis and early treatment of several rare, heritable conditions, preventing adverse health outcomes for most affected infants. New technological developments have enabled the implementation of testing panel covering over 50 disorders. Consequently, the increment of false positive rate has led to a high number of healthy infants recalled for expensive and often invasive additional testing, opening a debate about the harm-benefit ratio of the expanded newborn screening. The false-positive rate represents a challenge for healthcare providers working in NBS systems. Here, we give an overview on the most commonly used strategies for decreasing the adverse effects due to inconclusive screening results. The focus is on NBS performance improvement through the implementation of analytical methods, the application of new and more informative biomarkers, and by using post-analytical interpretive tools. These strategies, used as part of the NBS process, can to enhance the positive predictive value of the test and reduce the parental anxiety and healthcare costs related to the unnecessary tests and procedures.
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Lin Y, Chen D, Peng W, Wang K, Lin W, Zhuang J, Zheng Z, Li M, Fu Q. Newborn screening for isovaleric acidemia in Quanzhou, China. Clin Chim Acta 2020; 509:25-29. [PMID: 32505769 DOI: 10.1016/j.cca.2020.06.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 05/05/2020] [Accepted: 06/03/2020] [Indexed: 11/16/2022]
Abstract
BACKGROUND Isovaleric acidemia (IVA) is a rare autosomal recessive disorder of leucine metabolism caused by a defective isovaleryl-CoA dehydrogenase (IVD) gene. Reports of IVA diagnoses following newborn screening (NBS) in the Chinese population are few. METHODS We investigated the biochemical, clinical, and molecular profiles of 5 patients with IVA in China. The estimated incidence of IVA in Quanzhou, China is 1 in 1:84,469. RESULTS Initial NBS revealed mild to markedly increased isovalerylcarnitine (C5) concentrations in all 5 patients, and differential diagnosis revealed increased urinary isovaleryglycine concentrations in 2 patients. One patient presented with acute neonatal symptoms, whereas the other 4 remained asymptomatic. Eight distinct IVD gene variants were identified. The most common variant was c.1208A > G (p.Y403C), with an allele frequency of 30%. Five variants were previously unreported, namely, c.499A > G (p.M167V), c.640A > G (p.T214A), c.740G > A (p.G247E), c.832G > C (p.V278L), and c.1195G > C (p.D399H). Different in silico prediction analyses suggested that these previously unreported missense variants are pathogenic. Protein modelling analyses also showed that these missense variants may cause structural damage and dysfunction in IVD. CONCLUSIONS Patients with IVA may have C5 concentrations approaching the cut-off values, highlighting the need for stringent recall criteria and second-tier tests to improve screening performance.
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Affiliation(s)
- Yiming Lin
- Neonatal Disease Screening Center, Quanzhou Maternity and Children's Hospital, 700 Fengze Street, Quanzhou, Fujian Province 362000, China
| | - Dongmei Chen
- Department of Neonatal Intensive Care Unit, Quanzhou Maternity and Children's Hospital, 700 Fengze Street, Quanzhou, Fujian Province 362000, China
| | - Weilin Peng
- Neonatal Disease Screening Center, Quanzhou Maternity and Children's Hospital, 700 Fengze Street, Quanzhou, Fujian Province 362000, China
| | - Kunyi Wang
- Integrated Technical Service Center, Quanzhou Customs, Quanzhou, Fujian Province 362000, China
| | - Weihua Lin
- Neonatal Disease Screening Center, Quanzhou Maternity and Children's Hospital, 700 Fengze Street, Quanzhou, Fujian Province 362000, China
| | - Jianlong Zhuang
- Prenatal Diagnosis Center, Quanzhou Maternity and Children's Hospital, 700 Fengze Street, Quanzhou, Fujian Province 362000, China
| | - Zhenzhu Zheng
- Neonatal Disease Screening Center, Quanzhou Maternity and Children's Hospital, 700 Fengze Street, Quanzhou, Fujian Province 362000, China
| | - Min Li
- Hangzhou Genuine Clinical Laboratory Co. Ltd, Hangzhou, Zhejiang Province 310007, China.
| | - Qingliu Fu
- Neonatal Disease Screening Center, Quanzhou Maternity and Children's Hospital, 700 Fengze Street, Quanzhou, Fujian Province 362000, China.
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7
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Schlune A, Riederer A, Mayatepek E, Ensenauer R. Aspects of Newborn Screening in Isovaleric Acidemia. Int J Neonatal Screen 2018; 4:7. [PMID: 33072933 PMCID: PMC7548899 DOI: 10.3390/ijns4010007] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Accepted: 01/22/2018] [Indexed: 12/19/2022] Open
Abstract
Isovaleric acidemia (IVA), an inborn error of leucine catabolism, is caused by mutations in the isovaleryl-CoA dehydrogenase (IVD) gene, resulting in the accumulation of derivatives of isovaleryl-CoA including isovaleryl (C5)-carnitine, the marker metabolite used for newborn screening (NBS). The inclusion of IVA in NBS programs in many countries has broadened knowledge of the variability of the condition, whereas prior to NBS, two distinct clinical phenotypes were known, an "acute neonatal" and a "chronic intermittent" form. An additional biochemically mild and potentially asymptomatic form of IVA and its association with a common missense mutation, c.932C>T (p.A282V), was discovered in subjects identified through NBS. Deficiency of short/branched chain specific acyl-CoA dehydrogenase (2-methylbutyryl-CoA dehydrogenase), a defect of isoleucine degradation whose clinical significance remains unclear, also results in elevated C5-carnitine, and may therefore be detected by NBS for IVA. Treatment strategies for the long-term management of symptomatic IVA comprise the prevention of catabolism, dietary restriction of natural protein or leucine intake, and supplementation with l-carnitine and/or l-glycine. Recommendations on how to counsel and manage individuals with the mild phenotype detected by NBS are required.
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Affiliation(s)
- Andrea Schlune
- Experimental Pediatrics and Metabolism, Department of General Pediatrics, Neonatology and Pediatric Cardiology, Heinrich Heine University Düsseldorf, Moorenstrasse 5, 40225 Düsseldorf, Germany
| | - Anselma Riederer
- Department of Obstetrics and Gynecology, Hospital Altötting-Burghausen, Teaching Hospital of the Ludwig-Maximilians-Universität München, Vinzenz-von-Paul-Strasse 10, 84503 Altötting, Germany
| | - Ertan Mayatepek
- Experimental Pediatrics and Metabolism, Department of General Pediatrics, Neonatology and Pediatric Cardiology, Heinrich Heine University Düsseldorf, Moorenstrasse 5, 40225 Düsseldorf, Germany
| | - Regina Ensenauer
- Experimental Pediatrics and Metabolism, Department of General Pediatrics, Neonatology and Pediatric Cardiology, Heinrich Heine University Düsseldorf, Moorenstrasse 5, 40225 Düsseldorf, Germany
- Correspondence: ; Tel.: +49-211-81-17687
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8
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Raising Awareness of False Positive Newborn Screening Results Arising from Pivalate-Containing Creams and Antibiotics in Europe When Screening for Isovaleric Acidaemia. Int J Neonatal Screen 2018; 4:8. [PMID: 33072934 PMCID: PMC7510208 DOI: 10.3390/ijns4010008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/01/2018] [Accepted: 01/30/2018] [Indexed: 11/17/2022] Open
Abstract
While the early and asymptomatic recognition of treatable conditions offered by newborn screening confers clear health benefits for the affected child, the clinical referral of patients with screen positive results can cause significant harm for some families. The use of pivalate-containing antibiotics and more recently the inclusion of neopentanoate as a component within moisturising creams used as nipple balms by nursing mothers can result in a significant number of false positive results when screening for isovaleric acidaemia (IVA) by measuring C5 acylcarnitine. A recent survey conducted within centres from nine countries indicated that this form of contamination had been or was a significant confounding factor in the detection of IVA in seven of the nine who responded. In three of these seven the prominent cause was believed to derive from the use of moisturising creams and in another three from antibiotics containing pivalate; one country reported that the cause was mixed. As a result, four of these seven centres routinely perform second tier testing to resolve C5 isobars when an initial C5 result is elevated, and a fifth is considering making this change within their national programme. The use of creams containing neopentanoate by nursing mothers and evolving patterns in the prescription of pivalate-containing antibiotics during pregnancy require those involved in the design and operation of newborn screening programmes used to detect IVA and the doctors who receive clinical referrals from these programmes to maintain an awareness of the potential impact of this form of interference on patient results.
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9
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Beaudet AL. Brain carnitine deficiency causes nonsyndromic autism with an extreme male bias: A hypothesis. Bioessays 2017; 39. [PMID: 28703319 DOI: 10.1002/bies.201700012] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Could 10-20% of autism be prevented? We hypothesize that nonsyndromic or "essential" autism involves extreme male bias in infants who are genetically normal, but they develop deficiency of carnitine and perhaps other nutrients in the brain causing autism that may be amenable to early reversal and prevention. That brain carnitine deficiency might cause autism is suggested by reports of severe carnitine deficiency in autism and by evidence that TMLHE deficiency - a defect in carnitine biosynthesis - is a risk factor for autism. A gene on the X chromosome (SLC6A14) likely escapes random X-inactivation (a mixed epigenetic and genetic regulation) and could limit carnitine transport across the blood-brain barrier in boys compared to girls. A mixed, common gene variant-environment hypothesis is proposed with diet, minor illnesses, microbiome, and drugs as possible risk modifiers. The hypothesis can be tested using animal models and by a trial of carnitine supplementation in siblings of probands. Perhaps the lack of any Recommended Dietary Allowance for carnitine in infants should be reviewed. Also see the video abstract here: https://youtu.be/BuRH_jSjX5Y.
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Affiliation(s)
- Arthur L Beaudet
- Departments of Molecular and Human Genetics and Pediatrics, Baylor College of Medicine, Texas Children's Hospital, Houston, TX, USA
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10
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Minkler PE, Stoll MSK, Ingalls ST, Hoppel CL. Selective and accurate C5 acylcarnitine quantitation by UHPLC-MS/MS: Distinguishing true isovaleric acidemia from pivalate derived interference. J Chromatogr B Analyt Technol Biomed Life Sci 2017; 1061-1062:128-133. [PMID: 28734160 DOI: 10.1016/j.jchromb.2017.07.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 06/22/2017] [Accepted: 07/09/2017] [Indexed: 10/19/2022]
Abstract
Tandem MS acylcarnitine "profiles" are extremely valuable. Although used appropriately in newborn screening programs to identify patients with possible diseases, their inadequate quantitative accuracy and lack of selectivity is problematic for confirmatory testing. In this report, we show the application of our validated, selective, accurate, precise, and robust UHPLC-MS/MS method for quantitation of acylcarnitines, specifically to C5 acylcarnitines: pivaloyl-, 2-methylbutyryl-, isovaleryl-, and valerylcarnitine. Standardized calibrants were used to generate 13-point, 200-fold concentration range calibration curves. Samples were isolated by solid-phase extraction and derivatized with pentafluorophenacyl trifluoromethanesulfonate. Acylcarnitine pentafluorophenacyl esters were eluted in 14min chromatograms. Data demonstrating quantitative stability and method robustness over a five year time period are shown and these results validate the method's accuracy and robustness. Urine from patients with isovaleric acidemia (with the disease marker isovalerylcarnitine) and with pivaloylcarnitine present are shown. These results demonstrate the method's ability to distinguish true isovaleric acidemia from pivalate derived interference. Our method for acylcarnitine quantitation is shown to be accurate, precise, and robust for selective quantitation of isovalerylcarnitine, and thus is recommended for confirmatory testing of suspected isovaleric acidemia patients.
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Affiliation(s)
- Paul E Minkler
- Center for Mitochondrial Diseases, Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Maria S K Stoll
- Center for Mitochondrial Diseases, Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Stephen T Ingalls
- Center for Mitochondrial Diseases, Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Charles L Hoppel
- Center for Mitochondrial Diseases, Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA; Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
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11
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Introduction of a Simple Second Tier Screening Test for C5 Isobars in Dried Blood Spots: Reducing the False Positive Rate for Isovaleric Acidaemia in Expanded Newborn Screening. JIMD Rep 2017. [PMID: 28631226 DOI: 10.1007/8904_2017_33] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
In 2015 the English Newborn Screening programme expanded to include Isovaleric Acidaemia (IVA). Screening is performed by flow injection analysis tandem mass spectrometry of isovalerylcarnitine. Isovalerylcarnitine is isobaric with pivaloylcarnitine which can be present in blood due to the use of pivalic ester pro-drugs or pivalic acid derivatives used as emollients in some nipple creams; the potential for false positives (FP) is well documented. A pilot study in England screened 438,164 babies, 18 had presumptive positive results but only 4 were confirmed as true positives (TP). We developed a simple test to separate the isobaric compounds and investigate these samples further.We studied newborn screening blood spots from 122 randomised controls and 34 infants with an initial raised C5 result. Dried blood spots were eluted with 30% acetonitrile (150 μL) and injected into a Waters Acquity UPLC coupled to a Waters Premier XE tandem mass spectrometer operating in positive ion mode. Isocratic separation of isovalerylcarnitine, pivaloylcarnitine, valerylcarnitine and 2-methylbutyrylcarnitine was achieved within 8 min. Assay performance characteristics were acceptable and non-parametric reference ranges (n = 122) were determined for each analyte.If this method had been used as a second tier test for the 34 presumptive positive samples, the number of FP's would have reduced from 24 to 8 and the positive predictive value of the screening test would have increased from 29 to 56%. Introduction of this test into the screening protocol has the potential to significantly reduce FP results for IVA and prevent unnecessary anxiety.
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12
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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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13
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Poggiali S, Ombrone D, Forni G, Malvagia S, Funghini S, Mura M, Pasquini E, Santoro L, Bellavia V, Granata OM, Castana C, McGreevy KS, Aronica TS, la Marca G. Reducing the False-Positive Rate for Isovalerylcarnitine in Expanded Newborn Screening. JOURNAL OF INBORN ERRORS OF METABOLISM AND SCREENING 2016. [DOI: 10.1177/2326409816661355] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- Sara Poggiali
- Newborn Screening, Biochemistry and Pharmacology Laboratory, Pediatric Neurology Clinic and Laboratories, Meyer Children’s University Hospital, Florence, Italy
| | - Daniela Ombrone
- Newborn Screening, Biochemistry and Pharmacology Laboratory, Pediatric Neurology Clinic and Laboratories, Meyer Children’s University Hospital, Florence, Italy
| | - Giulia Forni
- Newborn Screening, Biochemistry and Pharmacology Laboratory, Pediatric Neurology Clinic and Laboratories, Meyer Children’s University Hospital, Florence, Italy
| | - Sabrina Malvagia
- Newborn Screening, Biochemistry and Pharmacology Laboratory, Pediatric Neurology Clinic and Laboratories, Meyer Children’s University Hospital, Florence, Italy
| | - Silvia Funghini
- Newborn Screening, Biochemistry and Pharmacology Laboratory, Pediatric Neurology Clinic and Laboratories, Meyer Children’s University Hospital, Florence, Italy
| | - Massimo Mura
- Newborn Screening, Biochemistry and Pharmacology Laboratory, Pediatric Neurology Clinic and Laboratories, Meyer Children’s University Hospital, Florence, Italy
| | - Elisabetta Pasquini
- Metabolic and Muscular Unit, Pediatric Neurology Clinic, Meyer Children’s University Hospital, Florence, Italy
| | - Laura Santoro
- UOS Newborn Screening Center, UOC Pediatric Clinical Pathology, P.O.G. Di Cristina, Palermo, Italy
| | - Vincenzo Bellavia
- UOS Newborn Screening Center, UOC Pediatric Clinical Pathology, P.O.G. Di Cristina, Palermo, Italy
| | - Orazia Maria Granata
- UOS Newborn Screening Center, UOC Pediatric Clinical Pathology, P.O.G. Di Cristina, Palermo, Italy
| | - Cinzia Castana
- UOC Pediatric Clinic, P.O.G. Di Cristina, Palermo, Italy
| | - Kathleen S. McGreevy
- Research, Innovation and International Relations Office, Meyer Children’s University Hospital, Florence, Italy
| | - Tommaso Silvano Aronica
- UOS Newborn Screening Center, UOC Pediatric Clinical Pathology, P.O.G. Di Cristina, Palermo, Italy
| | - Giancarlo la Marca
- Newborn Screening, Biochemistry and Pharmacology Laboratory, Pediatric Neurology Clinic and Laboratories, Meyer Children’s University Hospital, Florence, Italy
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
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14
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A Moderate Carnitine Deficiency Exacerbates Isoproterenol-Induced Myocardial Injury in Rats. Cardiovasc Drugs Ther 2016; 30:119-27. [DOI: 10.1007/s10557-016-6647-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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15
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Minkler PE, Stoll MSK, Ingalls ST, Kerner J, Hoppel CL. Quantitative acylcarnitine determination by UHPLC-MS/MS--Going beyond tandem MS acylcarnitine "profiles". Mol Genet Metab 2015; 116:231-41. [PMID: 26458767 PMCID: PMC5009370 DOI: 10.1016/j.ymgme.2015.10.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 10/06/2015] [Accepted: 10/07/2015] [Indexed: 01/22/2023]
Abstract
Tandem MS "profiling" of acylcarnitines and amino acids was conceived as a first-tier screening method, and its application to expanded newborn screening has been enormously successful. However, unlike amino acid screening (which uses amino acid analysis as its second-tier validation of screening results), acylcarnitine "profiling" also assumed the role of second-tier validation, due to the lack of a generally accepted second-tier acylcarnitine determination method. In this report, we present results from the application of our validated UHPLC-MS/MS second-tier method for the quantification of total carnitine, free carnitine, butyrobetaine, and acylcarnitines to patient samples with known diagnoses: malonic acidemia, short-chain acyl-CoA dehydrogenase deficiency (SCADD) or isobutyryl-CoA dehydrogenase deficiency (IBD), 3-methyl-crotonyl carboxylase deficiency (3-MCC) or ß-ketothiolase deficiency (BKT), and methylmalonic acidemia (MMA). We demonstrate the assay's ability to separate constitutional isomers and diastereomeric acylcarnitines and generate values with a high level of accuracy and precision. These capabilities are unavailable when using tandem MS "profiles". We also show examples of research interest, where separation of acylcarnitine species and accurate and precise acylcarnitine quantification is necessary.
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MESH Headings
- Acetyl-CoA C-Acyltransferase/blood
- Acetyl-CoA C-Acyltransferase/cerebrospinal fluid
- Acetyl-CoA C-Acyltransferase/deficiency
- Acetyl-CoA C-Acyltransferase/urine
- Acyl-CoA Dehydrogenase/blood
- Acyl-CoA Dehydrogenase/cerebrospinal fluid
- Acyl-CoA Dehydrogenase/deficiency
- Acyl-CoA Dehydrogenase/urine
- Amino Acid Metabolism, Inborn Errors/blood
- Amino Acid Metabolism, Inborn Errors/cerebrospinal fluid
- Amino Acid Metabolism, Inborn Errors/diagnosis
- Amino Acid Metabolism, Inborn Errors/urine
- Betaine/analogs & derivatives
- Betaine/blood
- Betaine/cerebrospinal fluid
- Betaine/urine
- Carbon-Carbon Ligases/blood
- Carbon-Carbon Ligases/cerebrospinal fluid
- Carbon-Carbon Ligases/deficiency
- Carbon-Carbon Ligases/urine
- Carnitine/analogs & derivatives
- Carnitine/blood
- Carnitine/cerebrospinal fluid
- Carnitine/urine
- Chromatography, High Pressure Liquid/methods
- Chromatography, High Pressure Liquid/standards
- Female
- Humans
- Infant, Newborn
- Isomerism
- Lipid Metabolism, Inborn Errors/blood
- Lipid Metabolism, Inborn Errors/cerebrospinal fluid
- Lipid Metabolism, Inborn Errors/diagnosis
- Lipid Metabolism, Inborn Errors/urine
- Male
- Neonatal Screening
- Reproducibility of Results
- Sensitivity and Specificity
- Tandem Mass Spectrometry/standards
- Urea Cycle Disorders, Inborn/blood
- Urea Cycle Disorders, Inborn/cerebrospinal fluid
- Urea Cycle Disorders, Inborn/diagnosis
- Urea Cycle Disorders, Inborn/urine
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Affiliation(s)
- Paul E Minkler
- Center for Mitochondrial Diseases, Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Maria S K Stoll
- Center for Mitochondrial Diseases, Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Stephen T Ingalls
- Center for Mitochondrial Diseases, Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Janos Kerner
- Center for Mitochondrial Diseases, Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Charles L Hoppel
- Center for Mitochondrial Diseases, Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA; Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
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16
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Yamada K, Kobayashi H, Bo R, Takahashi T, Hasegawa Y, Nakamura M, Ishige N, Yamaguchi S. Elevation of pivaloylcarnitine by sivelestat sodium in two children. Mol Genet Metab 2015; 116:192-4. [PMID: 26428892 DOI: 10.1016/j.ymgme.2015.09.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2015] [Revised: 09/24/2015] [Accepted: 09/24/2015] [Indexed: 11/21/2022]
Abstract
BACKGROUND Sivelestat sodium (sivelestat), a neutrophil elastase inhibitor, is used to treat acute respiratory distress syndrome (ARDS). We report two cases that developed elevated C5-acylcarnitine (C5-AC) levels following treatment with sivelestat. Case 1 was a 14-day-old female infant born at 25 weeks and 1 day of gestation who was treated with sivelestat for the prophylaxis of Wilson-Mikity syndrome soon after birth. Isovaleric acidemia (IVA) was suspected based on a newborn screening using tandem mass spectrometry (MS/MS). Her C5-AC level was elevated to 4.49 μM (cut-off, <1.0) after treatment with sivelestat. Case 2 was a 4-year-old female with pneumocystis pneumonia that developed during chemotherapy for disseminated medulloblastoma. Sivelestat was given for the complication of ARDS. Her C5-AC level increased (1.09 μM) after eight days of treatment with sivelestat. RESULTS In both cases, IVA was ruled out because isovalerylglycine was not observed in the urinary organic acid analysis. Case 1 was associated with carnitine deficiency (C0 9.16 μM; reference value, 10-60). Liquid chromatography-MS/MS confirmed elevated pivaloylcarnitine (PVC) in both cases. DISCUSSION Similar to antibiotics containing pivalic acid (PVA), sivelestat contains PVA, which has the potential to cause secondary carnitine deficiency. In addition, elevated PVC can lead to false positive findings of IVA in newborns screened using MS/MS.
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Affiliation(s)
- Kenji Yamada
- Department of Pediatrics, Shimane University Faculty of Medicine, 89-1 En-ya-cho, Izumo, Shimane 693-8501, Japan.
| | - Hironori Kobayashi
- Department of Pediatrics, Shimane University Faculty of Medicine, 89-1 En-ya-cho, Izumo, Shimane 693-8501, Japan
| | - Ryosuke Bo
- Department of Pediatrics, Shimane University Faculty of Medicine, 89-1 En-ya-cho, Izumo, Shimane 693-8501, Japan; Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
| | - Tomoo Takahashi
- Department of Pediatrics, Shimane University Faculty of Medicine, 89-1 En-ya-cho, Izumo, Shimane 693-8501, Japan
| | - Yuki Hasegawa
- Department of Pediatrics, Shimane University Faculty of Medicine, 89-1 En-ya-cho, Izumo, Shimane 693-8501, Japan
| | - Makoto Nakamura
- Department of Neonatology, Okayama Medical Center, 1711-1 Tamasu, Kita-ku, Okayama 701-1192, Japan
| | - Nobuyuki Ishige
- Tokyo Health Service Association, 1-2 Ichigayasadoharacho, Shinjuku-ku, Tokyo 162-8402, Japan
| | - Seiji Yamaguchi
- Department of Pediatrics, Shimane University Faculty of Medicine, 89-1 En-ya-cho, Izumo, Shimane 693-8501, Japan
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17
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Hall PL, Wittenauer A, Hagar A. Newborn screening for medium chain acyl-CoA dehydrogenase deficiency: performance improvement by monitoring a new ratio. Mol Genet Metab 2014; 113:274-7. [PMID: 25454677 DOI: 10.1016/j.ymgme.2014.10.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 10/06/2014] [Accepted: 10/06/2014] [Indexed: 11/22/2022]
Abstract
Medium chain acyl-CoA dehydrogenase (MCAD) deficiency is a fatty acid oxidation disorder included on newborn screening (NBS) panels in many regions that have expanded to using tandem mass spectrometry for acylcarnitine screening. False positive (FP) screening results for MCAD deficiency have previously been linked to very low birth weight (VLBW) infants and those who are heterozygous for the common mutation, p.K324E. Previous studies have identified these causes of FP screens by sequencing residual dried blood spots. From our cohort of FP screens in Georgia, we identified an elevation at the same mass as octenoylcarnitine (C8:1) causing elevations of octanoylcarnitine (C8) not due to MCAD deficiency. We reviewed biochemical results from 2011 to 2013 for all newborn screens positive for MCAD deficiency in Georgia to identify screening criteria to allow these cases to be identified prospectively, thus saving families the stress of additional testing on their newborn and reducing healthcare costs while improving screening performance for the screening program. We identified the C8/C8:1 ratio as an effective marker, and developed criteria that will reduce FP screening results due to this interfering substance.
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Affiliation(s)
- Patricia L Hall
- Emory Genetics Laboratory, Department of Human Genetics, Emory University, Atlanta, GA, United States.
| | - Angela Wittenauer
- Department of Human Genetics, Emory University, Atlanta, GA, United States
| | - Arthur Hagar
- Newborn Screening Laboratory, Georgia Department of Public Health, Decatur, GA, United States
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18
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Grünert SC. Clinical and genetical heterogeneity of late-onset multiple acyl-coenzyme A dehydrogenase deficiency. Orphanet J Rare Dis 2014; 9:117. [PMID: 25200064 PMCID: PMC4222585 DOI: 10.1186/s13023-014-0117-5] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 07/08/2014] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Multiple acyl-CoA dehydrogenase deficiency (MADD) is an autosomal recessive disorder caused by deficiency of electron transfer flavoprotein or electron transfer flavoprotein dehydrogenase. The clinical picture of late-onset forms is highly variable with symptoms ranging from acute metabolic decompensations to chronic, mainly muscular problems or even asymptomatic cases. METHODS All 350 cases of late-onset MADD reported in the literature to date have been analyzed and evaluated with respect to age at presentation, diagnostic delay, biochemical features and diagnostic parameters as well as response to treatment. RESULTS Mean age at onset was 19.2 years. The mean delay between onset of symptoms and diagnosis was 3.9 years. Chronic muscular symptoms were more than twice as common as acute metabolic decompensations (85% versus 33% of patients, respectively). 20% had both acute and chronic symptoms. 5% of patients had died at a mean age of 5.8 years, while 3% of patients have remained asymptomatic until a maximum age of 14 years. Diagnosis may be difficult as a relevant number of patients do not display typical biochemical patterns of urine organic acids and blood acylcarnitines during times of wellbeing. The vast majority of patients carry mutations in the ETFDH gene (93%), while mutations in the ETFA (5%) and ETFB (2%) genes are the exceptions. Almost all patients with late-onset MADD (98%) are clearly responsive to riboflavin. CONCLUSIONS Late-onset MADD is probably an underdiagnosed disease and should be considered in all patients with acute or chronic muscular symptoms or acute metabolic decompensation with hypoglycemia, acidosis, encephalopathy and hepatopathy. This may not only prevent patients from invasive diagnostic procedures such as muscle biopsies, but also help to avoid fatal metabolic decompensations.
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Affiliation(s)
- Sarah C Grünert
- Center of Pediatrics and Adolescent Medicine, University Hospital Freiburg, Freiburg, Germany.
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19
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Yahyaoui R, Rueda I, Dayaldasani A, Boemer F. [C5-carnitine false positive results in newborn screening: what is the cause?]. Med Clin (Barc) 2014; 144:181-2. [PMID: 24889749 DOI: 10.1016/j.medcli.2014.03.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 03/18/2014] [Accepted: 03/20/2014] [Indexed: 11/16/2022]
Affiliation(s)
- Raquel Yahyaoui
- Laboratorio de Metabolopatías, Centro de Cribado Neonatal de Andalucía Oriental, Hospital Regional de Málaga, Málaga, España.
| | - Inmaculada Rueda
- Laboratorio de Metabolopatías, Centro de Cribado Neonatal de Andalucía Oriental, Hospital Regional de Málaga, Málaga, España
| | - Anita Dayaldasani
- Laboratorio de Metabolopatías, Centro de Cribado Neonatal de Andalucía Oriental, Hospital Regional de Málaga, Málaga, España
| | - François Boemer
- Laboratorio de Bioquímica Genética, Genética Humana, Universidad de Liége, Liége, Bélgica
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