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Padilla CD, Therrell BL, Alcausin MMLB, Chiong MAD, Abacan MAR, Reyes MEL, Jomento CM, Dizon-Escoreal MTT, Canlas MAE, Abadingo ME, Posecion JEWC, Abarquez CG, Andal AP, Elizaga ALG, Halili-Mendoza BC, Otayza MPVK, Millington DS. Successful Implementation of Expanded Newborn Screening in the Philippines Using Tandem Mass Spectrometry. Int J Neonatal Screen 2022; 8:ijns8010008. [PMID: 35225931 PMCID: PMC8883932 DOI: 10.3390/ijns8010008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 12/23/2021] [Accepted: 01/12/2022] [Indexed: 11/29/2022] Open
Abstract
Newborn bloodspot screening (NBS) began as a research project in the Philippines in 1996 and was mandated by law in 2004. The program initially included screening for five conditions, with a sixth added in 2012. As screening technology and medical knowledge have advanced, NBS programs in countries with developed economies have also expanded, not only in the number of newborns screened but also in the number of conditions included in the screening. Various approaches have been taken regarding selection of conditions to be screened. With limited resources, low- and middle-income countries face significant challenges in selecting conditions for screening and in implementing sustainable screening programs. Building on expansion experiences in the U.S. and data from California on Filipinos born and screened there, the Philippine NBS program has recently completed its expansion to include 29 screening conditions. This report focuses on those conditions detectable through tandem mass spectrometry. Expanded screening was implemented in a stepwise fashion across the seven newborn screening laboratories in the Philippines. A university-based biochemical genetics laboratory provides confirmatory testing. Follow-up care for confirmed cases is monitored and provided through the NBS continuity clinics across the archipelago. Pre-COVID-19 pandemic, the coverage was 91.6% but dropped to 80.4% by the end of 2020 due to closure of borders between cities, provinces, and islands.
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Affiliation(s)
- Carmencita D. Padilla
- Newborn Screening Reference Center, National Institutes of Health, University of the Philippines Manila, Manila 1000, Philippines; (M.M.L.B.A.); (M.E.L.R.); (C.M.J.); (M.T.T.D.-E.); (M.A.E.C.); (M.E.A.)
- Department of Pediatrics, College of Medicine, University of the Philippines Manila, Manila 1000, Philippines; (M.A.D.C.); (M.A.R.A.)
- Institute of Human Genetics, National Institutes of Health, University of the Philippines Manila, Manila 1000, Philippines
- Correspondence:
| | - Bradford L. Therrell
- National Newborn Screening and Global Resource Center, Austin, TX 78759, USA;
- Department of Pediatrics, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Maria Melanie Liberty B. Alcausin
- Newborn Screening Reference Center, National Institutes of Health, University of the Philippines Manila, Manila 1000, Philippines; (M.M.L.B.A.); (M.E.L.R.); (C.M.J.); (M.T.T.D.-E.); (M.A.E.C.); (M.E.A.)
- Department of Pediatrics, College of Medicine, University of the Philippines Manila, Manila 1000, Philippines; (M.A.D.C.); (M.A.R.A.)
- Institute of Human Genetics, National Institutes of Health, University of the Philippines Manila, Manila 1000, Philippines
| | - Mary Anne D. Chiong
- Department of Pediatrics, College of Medicine, University of the Philippines Manila, Manila 1000, Philippines; (M.A.D.C.); (M.A.R.A.)
- Institute of Human Genetics, National Institutes of Health, University of the Philippines Manila, Manila 1000, Philippines
- Department of Biochemistry, Molecular Biology and Nutrition, Faculty of Medicine and Surgery, University of Santo Tomas, Manila 1008, Philippines
| | - Mary Ann R. Abacan
- Department of Pediatrics, College of Medicine, University of the Philippines Manila, Manila 1000, Philippines; (M.A.D.C.); (M.A.R.A.)
- Institute of Human Genetics, National Institutes of Health, University of the Philippines Manila, Manila 1000, Philippines
| | - Ma. Elouisa L. Reyes
- Newborn Screening Reference Center, National Institutes of Health, University of the Philippines Manila, Manila 1000, Philippines; (M.M.L.B.A.); (M.E.L.R.); (C.M.J.); (M.T.T.D.-E.); (M.A.E.C.); (M.E.A.)
| | - Charity M. Jomento
- Newborn Screening Reference Center, National Institutes of Health, University of the Philippines Manila, Manila 1000, Philippines; (M.M.L.B.A.); (M.E.L.R.); (C.M.J.); (M.T.T.D.-E.); (M.A.E.C.); (M.E.A.)
| | - Maria Truda T. Dizon-Escoreal
- Newborn Screening Reference Center, National Institutes of Health, University of the Philippines Manila, Manila 1000, Philippines; (M.M.L.B.A.); (M.E.L.R.); (C.M.J.); (M.T.T.D.-E.); (M.A.E.C.); (M.E.A.)
| | - Margarita Aziza E. Canlas
- Newborn Screening Reference Center, National Institutes of Health, University of the Philippines Manila, Manila 1000, Philippines; (M.M.L.B.A.); (M.E.L.R.); (C.M.J.); (M.T.T.D.-E.); (M.A.E.C.); (M.E.A.)
| | - Michelle E. Abadingo
- Newborn Screening Reference Center, National Institutes of Health, University of the Philippines Manila, Manila 1000, Philippines; (M.M.L.B.A.); (M.E.L.R.); (C.M.J.); (M.T.T.D.-E.); (M.A.E.C.); (M.E.A.)
| | | | - Conchita G. Abarquez
- Newborn Screening Center—Mindanao, Southern Philippine Medical Center, Davao 8000, Philippines;
| | - Alma P. Andal
- Newborn Screening Center—Southern Luzon, Daniel O. Mercado Medical Center, Tanauan 4232, Philippines;
| | - Anna Lea G. Elizaga
- Newborn Screening Center—National Institutes of Health, Quezon 1101, Philippines;
| | - Bernadette C. Halili-Mendoza
- Newborn Screening Center—Central Luzon, Angeles University Foundation Medical Center, Angeles 2009, Philippines;
| | - Maria Paz Virginia K. Otayza
- Newborn Screening Center—Northern Luzon, Mariano Marcos Memorial Hospital and Medical Center, Batac 2906, Philippines;
| | - David S. Millington
- Department of Pediatrics, Duke University School of Medicine, Durham, NC 27708, USA;
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Maceda EBG, Abadingo ME, Magbanua-Calalo CJ, Dator MA, Resontoc LPR, Castro-Hamoy LD, Abacan MAR, Chiong MAD, Estrada SC. Maple syrup urine disease associated with nephrotic syndrome in a Filipino child. BMJ Case Rep 2021; 14:14/7/e242689. [PMID: 34326111 PMCID: PMC8323351 DOI: 10.1136/bcr-2021-242689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
A 22-month-old female child with maple syrup urine disease (MSUD) presented with generalised oedema. Diagnostic evaluation revealed nephrotic range proteinuria, hypoalbuminaemia and dyslipidaemia supporting the diagnosis of nephrotic syndrome (NS). Diet, being at the core of the management plan for both MSUD and NS, necessitated regular monitoring and evaluation via dried blood spot collection of leucine. The opposing requirement for total protein for both disorders (that is protein restriction in MSUD and protein supplementation in NS) prompted a careful balancing act of the dietary management. The monitoring, which revealed normal leucine levels on multiple determinations, allowed an eventual increase in dietary protein and daily administration of albumin to address the NS. Dietary protein increase, both in total protein (3.5 g/kg/day) and natural protein (1 g/kg/day) levels, was instituted. It was observed that NS does not trigger leucinosis and allowed easing of protein restriction in MSUD.
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Affiliation(s)
- Ebner Bon G Maceda
- Division of Clinical Genetics, Department of Pediatrics, Philippine General Hospital, University of the Philippines Manila, Manila, Philippines .,Institute of Human Genetics, National Institutes of Health, University of the Philippines Manila, Manila, Philippines
| | - Michelle E Abadingo
- Division of Clinical Genetics, Department of Pediatrics, Philippine General Hospital, University of the Philippines Manila, Manila, Philippines.,Newborn Screening Reference Center, National Institutes of Health, University of the Philippines Manila, Manila, Philippines
| | - Cheryll J Magbanua-Calalo
- Division of Clinical Genetics, Department of Pediatrics, Philippine General Hospital, University of the Philippines Manila, Manila, Philippines.,Newborn Screening Reference Center, National Institutes of Health, University of the Philippines Manila, Manila, Philippines
| | - Melissa A Dator
- Division of Pediatric Nephrology, Department of Pediatrics, Philippine General Hospital, University of the Philippines Manila, Manila, Philippines
| | - Lourdes Paula R Resontoc
- Division of Pediatric Nephrology, Department of Pediatrics, Philippine General Hospital, University of the Philippines Manila, Manila, Philippines
| | - Leniza De Castro-Hamoy
- Division of Clinical Genetics, Department of Pediatrics, Philippine General Hospital, University of the Philippines Manila, Manila, Philippines.,Institute of Human Genetics, National Institutes of Health, University of the Philippines Manila, Manila, Philippines
| | - Mary Ann R Abacan
- Division of Clinical Genetics, Department of Pediatrics, Philippine General Hospital, University of the Philippines Manila, Manila, Philippines.,Institute of Human Genetics, National Institutes of Health, University of the Philippines Manila, Manila, Philippines
| | - Mary Anne D Chiong
- Division of Clinical Genetics, Department of Pediatrics, Philippine General Hospital, University of the Philippines Manila, Manila, Philippines.,Institute of Human Genetics, National Institutes of Health, University of the Philippines Manila, Manila, Philippines.,Department of Biochemistry, Molecular Biology and Nutrition, University of Santo Tomas Faculty of Medicine and Surgery, Manila, Philippines
| | - Sylvia C Estrada
- Division of Clinical Genetics, Department of Pediatrics, Philippine General Hospital, University of the Philippines Manila, Manila, Philippines.,Institute of Human Genetics, National Institutes of Health, University of the Philippines Manila, Manila, Philippines
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3
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O'Reilly D, Crushell E, Hughes J, Ryan S, Rogers Y, Borovickova I, Mayne P, Riordan M, Awan A, Carson K, Hunter K, Lynch B, Shahwan A, Rüfenacht V, Häberle J, Treacy EP, Monavari AA, Knerr I. Maple syrup urine disease: Clinical outcomes, metabolic control, and genotypes in a screened population after four decades of newborn bloodspot screening in the Republic of Ireland. J Inherit Metab Dis 2021; 44:639-655. [PMID: 33300147 DOI: 10.1002/jimd.12337] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 11/05/2020] [Accepted: 12/07/2020] [Indexed: 12/27/2022]
Abstract
Since 1972, 18 patients (10 females/8 males) have been detected by newborn bloodspot screening (NBS) with neonatal-onset maple syrup urine disease (MSUD) in Ireland. Patients were stratified into three clusters according to clinical outcome at the time of data collection, including developmental, clinical, and IQ data. A fourth cluster comprised of two early childhood deaths; a third patient died as an adult. We present neuroimaging and electroencephalography together with clinical and biochemical data. Incidence of MSUD (1972-2018) was 1 in 147 975. Overall good clinical outcomes were achieved with 15/18 patients alive and with essentially normal functioning (with only the lowest performing cluster lying beyond a single SD on their full scale intelligence quotient). Molecular genetic analysis revealed genotypes hitherto not reported, including a possible digenic inheritance state for the BCKDHA and DBT genes in one family. Treatment has been based on early implementation of emergency treatment, diet, close monitoring, and even dialysis in the setting of acute metabolic decompensation. A plasma leucine ≥400 μmol/L (outside therapeutic range) was more frequently observed in infancy or during adolescence, possibly due to infections, hormonal changes, or noncompliance. Children require careful management during metabolic decompensations in early childhood, and this represented a key risk period in our cohort. A high level of metabolic control can be achieved through diet with early implementation of a "sick day" regime and, in some cases, dialysis as a rescue therapy. The Irish cohort, despite largely classical phenotypes, achieved good outcomes in the NBS era, underlining the importance of early diagnosis and skilled multidisciplinary team management.
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Affiliation(s)
- Daniel O'Reilly
- National Centre for Inherited Metabolic Disorders, Children's Health Ireland at Temple Street, Dublin, Ireland
| | - Ellen Crushell
- National Centre for Inherited Metabolic Disorders, Children's Health Ireland at Temple Street, Dublin, Ireland
| | - Joanne Hughes
- National Centre for Inherited Metabolic Disorders, Children's Health Ireland at Temple Street, Dublin, Ireland
| | - Stephanie Ryan
- Department of Paediatric Radiology, Children's Health Ireland at Temple Street, Dublin, Ireland
| | - Yvonne Rogers
- National Centre for Inherited Metabolic Disorders, Children's Health Ireland at Temple Street, Dublin, Ireland
| | - Ingrid Borovickova
- Metabolic Laboratory, Children's Health Ireland at Temple Street, Dublin, Ireland
- National Newborn Screening Laboratory, Children's Health Ireland at Temple Street, Dublin, Ireland
| | - Philip Mayne
- Metabolic Laboratory, Children's Health Ireland at Temple Street, Dublin, Ireland
- National Newborn Screening Laboratory, Children's Health Ireland at Temple Street, Dublin, Ireland
| | - Michael Riordan
- Department of Nephrology, Children's Health Ireland at Temple Street, Dublin, Ireland
| | - Atif Awan
- Department of Nephrology, Children's Health Ireland at Temple Street, Dublin, Ireland
| | - Kevin Carson
- Paediatric Intensive Care Unit, Children's Health Ireland at Temple Street, Dublin, Ireland
| | - Kim Hunter
- Paediatric Intensive Care Unit, Children's Health Ireland at Temple Street, Dublin, Ireland
| | - Bryan Lynch
- Department of Neurology, Children's Health Ireland at Temple Street, Dublin, Ireland
| | - Amre Shahwan
- Department of Neurology, Children's Health Ireland at Temple Street, Dublin, Ireland
| | - Véronique Rüfenacht
- Division of Metabolism and Children's Research Centre, University Children's Hospital, Zurich, Switzerland
| | - Johannes Häberle
- Division of Metabolism and Children's Research Centre, University Children's Hospital, Zurich, Switzerland
| | - Eileen P Treacy
- Adult Metabolic Services/National Centre for Inherited Metabolic Disorders, Mater Misericordiae University Hospital, Dublin, Ireland
| | - Ahmad A Monavari
- National Centre for Inherited Metabolic Disorders, Children's Health Ireland at Temple Street, Dublin, Ireland
| | - Ina Knerr
- National Centre for Inherited Metabolic Disorders, Children's Health Ireland at Temple Street, Dublin, Ireland
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Abadingo ME, Abacan MAR, Basas JRU, Padilla CD. Pregnancy in an adolescent with maple syrup urine disease: Case report. Mol Genet Metab Rep 2021; 27:100745. [PMID: 33868929 PMCID: PMC8042167 DOI: 10.1016/j.ymgmr.2021.100745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/07/2021] [Accepted: 03/09/2021] [Indexed: 11/27/2022] Open
Abstract
Maple syrup urine disease (MSUD, MIM #248600) is an autosomal recessive metabolic disorder that results in elevation of the branched-chain amino acids (BCAA) leucine, isoleucine, and valine. Elevation of BCAA and certain alpha keto-acids is associated with a catabolic state and may result in neurological and developmental delays, feeding problems, and a urine and cerumen odor of maple syrup. Pregnancy is a period of multiple adaptations necessary to support fetal growth and development. Both the third trimester of pregnancy and the postpartum period present the possibility for catabolic states. We describe our treatment of an adolescent patient with intermittent MSUD and her resulting positive pregnancy outcome.
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Affiliation(s)
- Michelle E Abadingo
- Division of Clinical and Metabolic Genetics, Department of Pediatrics, University of the Philippines - Philippine General Hospital, Manila, Philippines.,Institute of Human Genetics, National Institutes of Health, University of the Philippines, Manila, Philippines.,Newborn Screening Reference Center, National Institutes of Health, University of the Philippines, Manila, Philippines
| | - Mary Ann R Abacan
- Division of Clinical and Metabolic Genetics, Department of Pediatrics, University of the Philippines - Philippine General Hospital, Manila, Philippines.,Institute of Human Genetics, National Institutes of Health, University of the Philippines, Manila, Philippines
| | - Jeanne Ruth U Basas
- Institute of Human Genetics, National Institutes of Health, University of the Philippines, Manila, Philippines
| | - Carmencita D Padilla
- Division of Clinical and Metabolic Genetics, Department of Pediatrics, University of the Philippines - Philippine General Hospital, Manila, Philippines.,Institute of Human Genetics, National Institutes of Health, University of the Philippines, Manila, Philippines.,Newborn Screening Reference Center, National Institutes of Health, University of the Philippines, Manila, Philippines
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5
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Ma S, Zhang Z, Fu Y, Zhang M, Niu Y, Li R, Guo Q, He Z, Zhao Q, Song Z, Wang X, Sun R. Identification of the first Alu-mediated gross deletion involving the BCKDHA gene in a compound heterozygous patient with maple syrup urine disease. Clin Chim Acta 2021; 517:23-30. [PMID: 33607070 DOI: 10.1016/j.cca.2021.01.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 01/31/2021] [Accepted: 01/31/2021] [Indexed: 11/25/2022]
Abstract
AIMS To investigate a family with clinical symptoms of maple syrup urine disease and reveal a genetic cause underlying this disease. METHODS Targeted capture sequencing was used to screen for mutations in the patient. Real-Time PCR was carried out to perform exon 1, 5, 9 CNV analysis of samples from the patient's father, mother and sister. Whole genome sequencing was performed to map the approximate location of the break points of the gross deletion. Long-range PCR and Sanger sequencing were performed to identify the length of the deletion and to locate the break points. RESULTS The patient is a compound heterozygous mutation including a small deletion mutation (c.1227_1229del chr19: 41930402) and a gross novel deletion including exon1-9 in BCKDHA. The junction site of the gross deletion was localized within a microhomologous sequence in two Alu elements. CONCLUSIONS This study is the first time report on rearrangement sequences in BCKDHA mediated by Alu element, which resulted in MSUD. Our results may also offer new insights into the formation and pathogenicity of MSUD, and may be useful to genetic counseling and genetic testing.
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Affiliation(s)
- Shujun Ma
- Henan Collaborative Innovation Center of Molecular Diagnosis and Laboratory Medicine, School of Laboratory Medicine, Xinxiang Medical University, China; Henan Key Laboratory of Immunology and Targeted Drugs, School of Laboratory Medicine, Xinxiang Medical University, China.
| | - Zhongxin Zhang
- Henan Collaborative Innovation Center of Molecular Diagnosis and Laboratory Medicine, School of Laboratory Medicine, Xinxiang Medical University, China
| | - Yanyan Fu
- The Second Affiliated Hospital of Xinxiang Medical University, Xinxiang 453003, China
| | - Mingxia Zhang
- Xinxiang Maternity and Child Care Hospital, Xinxiang 453003, China
| | - Yuna Niu
- Henan Key Laboratory of Immunology and Targeted Drugs, School of Laboratory Medicine, Xinxiang Medical University, China
| | - Ruiguang Li
- Henan Collaborative Innovation Center of Molecular Diagnosis and Laboratory Medicine, School of Laboratory Medicine, Xinxiang Medical University, China
| | - Qinghe Guo
- Henan Collaborative Innovation Center of Molecular Diagnosis and Laboratory Medicine, School of Laboratory Medicine, Xinxiang Medical University, China
| | - Zhian He
- Henan Collaborative Innovation Center of Molecular Diagnosis and Laboratory Medicine, School of Laboratory Medicine, Xinxiang Medical University, China
| | - Qingwei Zhao
- Henan Collaborative Innovation Center of Molecular Diagnosis and Laboratory Medicine, School of Laboratory Medicine, Xinxiang Medical University, China
| | - Zhishan Song
- Henan Collaborative Innovation Center of Molecular Diagnosis and Laboratory Medicine, School of Laboratory Medicine, Xinxiang Medical University, China
| | - Xia Wang
- Henan Collaborative Innovation Center of Molecular Diagnosis and Laboratory Medicine, School of Laboratory Medicine, Xinxiang Medical University, China
| | - Ruili Sun
- Henan Key Laboratory of Immunology and Targeted Drugs, School of Laboratory Medicine, Xinxiang Medical University, China
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6
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Ali EZ, Ngu LH. Fourteen new mutations of BCKDHA, BCKDHB and DBT genes associated with maple syrup urine disease (MSUD) in Malaysian population. Mol Genet Metab Rep 2018; 17:22-30. [PMID: 30228974 PMCID: PMC6140420 DOI: 10.1016/j.ymgmr.2018.08.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 08/30/2018] [Accepted: 08/30/2018] [Indexed: 12/11/2022] Open
Abstract
Maple syrup urine disease (MSUD) is a rare autosomal recessive metabolic disorder. This disorder is usually caused by mutations in any one of the genes; BCKDHA, BCKDHB and DBT, which represent E1α, E1β and E2 subunits of the branched-chain α-keto acid dehydrogenase (BCKDH) complex, respectively. This study presents the molecular characterization of 31 MSUD patients. Twenty one mutations including 14 new mutations were identified. The BCKDHB gene was the most commonly affected (45.2%) compared to BCKDHA gene (16.1%) and DBT gene (38.7%). In silico webservers predicted all mutations were disease-causing. In addition, structural evaluation disclosed that all new missenses in BCKDHA, BCKDHB and DBT genes affected stability and formation of E1 and E2 subunits. Majority of the patients had neonatal onset MSUD (26 of 31). Meanwhile, the new mutation; c.1196C > G (p.S399C) in DBT gene was noted to be recurrent and found in 9 patients. Conclusion: Our findings have expanded the mutational spectrum of the MSUD and revealed the genetic heterogeneity among Malaysian MSUD patients. We also discovered the p.S399C from DBT gene was noted as a recurrent mutation in Malay community and it suggested the existence of common and unique mutation in Malay population.
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Affiliation(s)
- Ernie Zuraida Ali
- Molecular Diagnostics and Protein Unit, Specialized Diagnostics Centre, Institute for Medical Research, Jalan Pahang, 50588 Kuala Lumpur, Malaysia
| | - Lock-Hock Ngu
- Medical Genetics Department, Kuala Lumpur Hospital, Jalan Pahang, 50588 Kuala Lumpur, Malaysia
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De Castro-Hamoy LG, Chiong MAD, Estrada SC, Cordero CP. Challenges in the management of patients with maple syrup urine disease diagnosed by newborn screening in a developing country. J Community Genet 2017; 8:9-15. [PMID: 27714667 PMCID: PMC5222756 DOI: 10.1007/s12687-016-0281-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 09/23/2016] [Indexed: 12/21/2022] Open
Abstract
Maple syrup urine disease (MSUD) is a rare inborn error of metabolism resulting from a deficiency in the branched-chain alpha-ketoacid dehydrogenase complex. MSUD has been reported to be the most common inborn error of metabolism in the Philippines. We described all patients with maple syrup urine disease patients diagnosed through newborn screening during its first 2 years of implementation and the challenges encountered during their medical management. There were 24 patients diagnosed with maple syrup urine disease for the 2-year period. All patients needed hospital admission. The most common complication during hospital admission was infection, needing intravenous antibiotics which were given to 21 of the patients. Out of the 24 diagnosed, 16 patients are alive, while eight have died. Several neurologic and non-neurologic complications have been observed during the follow-up of the patients. The common challenges of MSUD management in a low-resource setting identified in this study were late diagnosis, lack of access to metabolic specialists and medical supplies, nosocomial septicemia, and protein deficiency. Aside from early properly timed collection, improvement in other logistical concerns will also help in earlier diagnosis. Mechanisms of transfer of critically ill patients must be improved. Hospitals in difficult-to-reach areas must be equipped to handle critical metabolic cases when transfers are not possible. Newborn screening has been proven to improve outcome in patients with MSUD but the success of the program in preventing disability is also dependent on improvements in other aspects of healthcare.
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Affiliation(s)
- Leniza G De Castro-Hamoy
- Department of Pediatrics, Section of Clinical Genetics, University of the Philippines-Philippine General Hospital, Manila, Philippines.
- Institute of Human Genetics-National Institutes of Health, University of the Philippines Manila, Manila Pedro Gil Street, Malate, 1000, P.O. Box 297, Manila, Philippines.
| | - Mary Anne D Chiong
- Department of Pediatrics, Section of Clinical Genetics, University of the Philippines-Philippine General Hospital, Manila, Philippines
- Institute of Human Genetics-National Institutes of Health, University of the Philippines Manila, Manila Pedro Gil Street, Malate, 1000, P.O. Box 297, Manila, Philippines
| | - Sylvia C Estrada
- Department of Pediatrics, Section of Clinical Genetics, University of the Philippines-Philippine General Hospital, Manila, Philippines
- Institute of Human Genetics-National Institutes of Health, University of the Philippines Manila, Manila Pedro Gil Street, Malate, 1000, P.O. Box 297, Manila, Philippines
| | - Cynthia P Cordero
- Institute of Human Genetics-National Institutes of Health, University of the Philippines Manila, Manila Pedro Gil Street, Malate, 1000, P.O. Box 297, Manila, Philippines
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8
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Chiong MAD, Tan MA, Cordero CP, Fodra EGD, Manliguis JS, Lopez CP, Dalmacio LMM. Plasma amino acid and urine organic acid profiles of Filipino patients with maple syrup urine disease (MSUD) and correlation with their neurologic features. Mol Genet Metab Rep 2016; 9:46-53. [PMID: 27761412 PMCID: PMC5065041 DOI: 10.1016/j.ymgmr.2016.10.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 10/06/2016] [Accepted: 10/06/2016] [Indexed: 01/31/2023] Open
Abstract
Background Maple syrup urine disease (MSUD) is the most common inborn error of metabolism in the country. The cause of the neuropathology is still not well established although accumulation of branched chain amino acids (BCAA) and alteration in large neutral amino acids (LNAA) as well as energy deprivation are suggested. It is therefore the aim of this study to determine the plasma amino acid and urine organic acid profiles of patients with MSUD and correlate the findings with their neurologic features. Methodology Twenty six Filipino patients with MSUD were studied in terms of their plasma amino acid and urine organic acid profiles. Their results were compared with 26 age and sex matched controls. The neurologic features were correlated with the results of the plasma amino acids and urine organic acids. Results Majority of the patients with MSUD had developmental delay/intellectual disability (88%), speech delay (69%), and seizures (65%). Their amino acid profiles revealed low glutamine and alanine with high levels of leucine, isoleucine, phenylalanine, threonine and alloisoleucine compared to controls (p < 0.05). The urine organic acids showed significantly elevated excretion of the branched chain ketoacids and succinate (p < 0.05). However there were no biochemical markers that correlated significantly with the neurologic features. Conclusion The findings suggest that there could still be altered LNAA metabolism among patients with MSUD when the BCAAs are elevated. Although the biochemical findings were not significantly correlated with the neurologic features, the study showed that prevention and avoidance of neurologic disturbances may still rely primarily on early diagnosis and prompt institution of treatment, along with strict compliance with the dietary regimen and maintenance of good metabolic control over time.
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Affiliation(s)
- Mary Anne D Chiong
- Institute of Human Genetics, National Institutes of Health, University of the Philippines Manila, Philippines
| | - Marilyn A Tan
- Department of Pediatrics, Section of Neurology, Philippine General Hospital, University of the Philippines Manila, Philippines
| | - Cynthia P Cordero
- Department of Clinical Epidemiology, University of the Philippines Manila, Philippines
| | - Esphie Grace D Fodra
- Institute of Human Genetics, National Institutes of Health, University of the Philippines Manila, Philippines
| | - Judy S Manliguis
- Institute of Human Genetics, National Institutes of Health, University of the Philippines Manila, Philippines
| | - Cristine P Lopez
- Institute of Human Genetics, National Institutes of Health, University of the Philippines Manila, Philippines
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9
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Padilla CD, Cutiongco-de la Paz EM. Genetics and genomic medicine in the Philippines. Mol Genet Genomic Med 2016; 4:494-503. [PMID: 27652277 PMCID: PMC5023934 DOI: 10.1002/mgg3.247] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Genetics and genomic medicine in the Philippines.
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Affiliation(s)
- Carmencita D Padilla
- Department of PediatricsCollege of MedicineUniversity of the Philippines ManilaManilaPhilippines; Institute of Human GeneticsNational Institutes of HealthUniversity of the Philippines ManilaManilaPhilippines; Philippine Genome CenterUniversity of the Philippines SystemQuezon CityPhilippines
| | - Eva Maria Cutiongco-de la Paz
- Department of PediatricsCollege of MedicineUniversity of the Philippines ManilaManilaPhilippines; Institute of Human GeneticsNational Institutes of HealthUniversity of the Philippines ManilaManilaPhilippines; Philippine Genome CenterUniversity of the Philippines SystemQuezon CityPhilippines
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Hou JW, Hwang TL. Different gene preferences of maple syrup urine disease in the aboriginal tribes of Taiwan. Pediatr Neonatol 2014; 55:213-7. [PMID: 24268812 DOI: 10.1016/j.pedneo.2013.09.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 08/27/2013] [Accepted: 09/23/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Maple syrup urine disease (MSUD) is a rare inborn error of metabolism caused by a deficiency of the branched-chain α-ketoacid dehydrogenase (BCKD) complex. Mutations in any one of the three different genes encoding for the BCKD components, namely, BCKDHA, BCKDHB, and DBT, may be responsible for this disease. In Taiwan, few MSUD cases were diagnosed clinically, and most of these patients are from Aboriginal tribes. MATERIALS AND METHODS To identify and detect the carrier frequency of MSUD in Taiwanese Aboriginal tribes, we performed biochemical and molecular studies from peripheral blood in MSUD patients and dried blood on filter paper in the enrolled screened populations. RESULTS Homozygous A208T and I281T of BCKDHA were found in two patients from Hans (non-Aboriginal Taiwanese), respectively; compound heterozygous mutations of the DBT gene [4.7 kb deletion/c.650-651insT (L217F or L217fsX223) and c.650-651insT/c.88-89delAT] were found in two patients from Amis, respectively, after direct DNA sequencing and polymerase chain reaction-restriction fragment length polymorphism studies. There were no cases of deleted 4.7-kb heterozygote out of 302 normal people (Hans, n = 125; Atayal, n = 156; and Saisiyat, n = 21); by contrast, the DBT mutations c.650-651insT and deleted 4.7-kb heterozygote were noted in 2/121 and 1/121, respectively, from the general population of the Amis, a southeastern Taiwanese tribe. CONCLUSION Although the Taiwanese Austronesian Aboriginal tribes are considered to share a common origin, different gene preferences of MSUD were noted. The novel DBT mutation c.650-651insT was more prevalent than the deleted 4.7-kb heterozygote in the Amis population. The reported 4.7-kb deletion indicating a possible founder mutation may be preserved in the southern and eastern, but not in northern Aboriginal tribes of Taiwan.
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Affiliation(s)
- Jia-Woei Hou
- Department of Pediatrics, Cathay General Hospital, Taipei, Taiwan; Department of Pediatrics, Fu-Jen Catholic University School of Medicine, New Taipei City, Taiwan.
| | - Tsann-Long Hwang
- Department of Surgery, Chang Gung University School of Medicine, Taoyuan, Taiwan
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Jaafar N, Moleirinho A, Kerkeni E, Monastiri K, Seboui H, Amorim A, Prata MJ, Quental S. Molecular characterization of maple syrup urine disease patients from Tunisia. Gene 2013; 517:116-9. [PMID: 23313820 DOI: 10.1016/j.gene.2012.12.097] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2012] [Revised: 11/30/2012] [Accepted: 12/14/2012] [Indexed: 11/30/2022]
Abstract
Maple syrup urine disease (MSUD) is a rare disorder of branched-chain amino acids (BCAA) metabolism caused by the defective function of branched-chain α-ketoacid dehydrogenase complex (BCKD). The disease causal mutations can occur either in BCKDHA, BCKDHB or DBT genes encoding respectively the E1α, E1β and E2 subunits of the complex. In this study we report the molecular characterization of 3 Tunisian patients with the classic form of MSUD. Two novel putative mutations have been identified: the alteration c.716A>G (p.Glu239Gly) in BCKDHB and a small deletion (c.1333_1336delAATG; p.Asn445X) detected in DBT gene.
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Affiliation(s)
- N Jaafar
- Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Rua Dr. Roberto Frias s/n, 4200-465 Porto, Portugal
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12
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Vatanavicharn N, Ratanarak P, Liammongkolkul S, Sathienkijkanchai A, Wasant P. Amino acid disorders detected by quantitative amino acid HPLC analysis in Thailand: an eight-year experience. Clin Chim Acta 2012; 413:1141-4. [PMID: 22465081 DOI: 10.1016/j.cca.2012.03.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Revised: 03/16/2012] [Accepted: 03/20/2012] [Indexed: 10/28/2022]
Abstract
BACKGROUND Amino acid disorders are a major group of inborn errors of metabolism (IEM) with variable clinical presentations. This study was aimed to provide the data of amino acid disorders detected in high-risk Thai patients referred to our metabolic lab from all over the country. METHODS From 2001 to 2009, we analyzed amino acids by HPLC in 1214 plasma and cerebrospinal fluid specimens. These specimens were obtained from patients with clinical suspicion of IEM or with positive newborn screening. The clinical data of the patients with confirmed diagnoses of amino acid disorders were also analyzed. RESULTS Fifty-eight patients were diagnosed with amino acid disorders, including 20 cases (34.5%) with maple syrup urine disease, 13 (22.4%) with phenylketonuria and hyperphenylalaninemia, 13 (22.4%) with nonketotic hyperglycinemia, 9 (15.5%) with urea cycle defects, 2 (3.4%) with classical homocystinuria, and 1 (1.7%) with ornithine aminotransferase deficiency. There was considerable delay in diagnoses which led to poor outcomes in most patients. CONCLUSION The prevalence of amino acid disorders in Thailand is distinct from other countries. This will guide the selection of the prevalent IEM for the future expansion of newborn screening program in this country.
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Affiliation(s)
- Nithiwat Vatanavicharn
- Division of Medical Genetics, Department of Pediatrics, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
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Niu DM, Chien YH, Chiang CC, Ho HC, Hwu WL, Kao SM, Chiang SH, Kao CH, Liu TT, Chiang H, Hsiao KJ. Nationwide survey of extended newborn screening by tandem mass spectrometry in Taiwan. J Inherit Metab Dis 2010; 33:S295-305. [PMID: 20567911 DOI: 10.1007/s10545-010-9129-z] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Revised: 05/07/2010] [Accepted: 05/10/2010] [Indexed: 11/26/2022]
Abstract
In Taiwan, during the period March 2000 to June 2009, 1,495,132 neonates were screened for phenylketonuria (PKU) and homocystinuria (HCU), and 1,321,123 neonates were screened for maple syrup urine disease (MSUD), methylmalonic academia (MMA), medium-chain acyl-coenzyme A (CoA) dehydrogenase (MCAD) deficiency, isovaleric academia (IVA), and glutaric aciduria type 1 (GA-1) using tandem mass spectrometry (MS/MS). In a pilot study, 592,717 neonates were screened for citrullinemia, 3-methylcrotonyl-CoA carboxylase deficiency (3-MCC) and other fatty acid oxidation defects in the MS/MS newborn screening. A total of 170 newborns and four mothers were confirmed to have inborn errors of metabolism. The overall incidence was approximately 1/5,882 (1/6,219 without mothers). The most common inborn errors were defects of phenylalanine metabolism [five classic PKU, 20 mild PKU, 40 mild hyperphenylalaninemia (HPA), and 13 6-pyruvoyl-tetrahydropterin synthase (PTPS) deficiency]. MSUD was the second most common amino acidopathy and, significantly, most MSUD patients (10/13) belonged to the Austronesian aboriginal tribes of southern Taiwan. The most frequently detected among organic acid disorders was 3-MCC deficiency (14 newborns and four mothers). GA-1 and MMA were the second most common organic acid disorders (13 and 13 newborns, respectively). In fatty acid disorders, five carnitine transport defect (CTD), five short-chain acyl-CoA dehydrogenase deficiency (SCAD), and two medium-chain acyl-CoA dehydrogenase (MCAD) deficiency were confirmed. This is the largest case of MS/MS newborn screening in an East-Asian population to date. We hereby report the incidences and outcomes of metabolic inborn error diseases found in our nationwide MS/MS newborn screening program.
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Affiliation(s)
- Dau-Ming Niu
- Institute of Clinical Medicine, School of Medicine, National Yang Ming University, No.155, Sec.2, Linong Street, Taipei, Taiwan.
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14
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Phylipsen M, Vogelaar IP, Schaap RA, Arkesteijn SG, Boxma GL, van Helden WC, Wildschut IC, de Bruin-Roest AC, Giordano PC, Harteveld CL. A new α0-thalassemia deletion found in a Dutch family (--AW). Blood Cells Mol Dis 2010; 45:133-5. [DOI: 10.1016/j.bcmd.2010.05.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Revised: 05/05/2010] [Accepted: 05/05/2010] [Indexed: 11/28/2022]
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15
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Zhang Z, Yagi M, Okizuka Y, Awano H, Takeshima Y, Matsuo M. Insertion of the IL1RAPL1 gene into the duplication junction of the dystrophin gene. J Hum Genet 2009; 54:466-73. [PMID: 19609279 DOI: 10.1038/jhg.2009.63] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Duplications of one or more exons of the dystrophin gene are the second most common mutation in dystrophinopathies. Even though duplications are suggested to occur with greater complexity than thought earlier, they have been considered an intragenic event. Here, we report the insertion of a part of the IL1RAPL1 (interleukin-1 receptor accessory protein-like 1) gene into the duplication junction site. When the actual exon junction was examined in 15 duplication mutations in the dystrophin gene by analyzing dystrophin mRNA, one patient was found to have an unknown 621 bp insertion at the junction of duplication of exons from 56 to 62. Unexpectedly, the inserted sequence was found completely identical to sequences of exons 3-5 of the IL1RAPL1 gene that is nearly 100 kb distal from the dystrophin gene. Accordingly, the insertion of IL1RAPL1 exons 3-5 between dystrophin exons 62 and 56 was confirmed at the genomic sequence level. One junction between the IL1RAPL1 intron 5 and dystrophin intron 55 was localized within an Alu sequence. These results showed that a fragment of the IL1RAPL1 gene was inserted into the duplication junction of the dystrophin gene in the same direction as the dystrophin gene. This suggests the novel possibility of co-occurrence of complex genomic rearrangements in dystrophinopathy.
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Affiliation(s)
- Zhujun Zhang
- Department of Pediatrics, Kobe University Graduate School of Medicine, Chuo, Kobe, Japan
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16
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Skvorak KJ. Animal models of maple syrup urine disease. J Inherit Metab Dis 2009; 32:229-46. [PMID: 19263237 DOI: 10.1007/s10545-009-1086-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2008] [Revised: 12/15/2008] [Accepted: 12/18/2008] [Indexed: 01/03/2023]
Abstract
Maple syrup urine disease (MSUD) is an inherited aminoacidopathy resulting from dysfunction of the branched-chain keto acid dehydrogenase (BCKDH) complex. This disease is currently treated primarily by dietary restriction of branched-chain amino acids (BCAAs). However, dietary compliance is often challenging. Conversely, liver transplantation significantly improves outcomes, but donor organs are scarce and there are high costs and potential risks associated with this invasive procedure. Therefore, improved treatment options for MSUD are needed. Development of novel treatments could be facilitated by animal models that accurately mimic the human disease. Animal models provide a useful system in which to explore disease mechanisms and new preclinical therapies. Here we review MSUD and currently available animal models and their corresponding relevance to the human disorder. Using animal models to gain a more complete understanding of the pathophysiology behind the human disease may lead to new or improved therapies to treat or potentially cure the disorder.
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Affiliation(s)
- K J Skvorak
- Graduate Program in the Department of Molecular Genetics and Biochemistry, University of Pittsburgh, Pittsburgh, PA, USA.
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Lee JY, Chiong MA, Estrada SC, Cutiongco-De la Paz EM, Silao CLT, Padilla CD. Maple syrup urine disease (MSUD)--clinical profile of 47 Filipino patients. J Inherit Metab Dis 2008; 31 Suppl 2:S281-5. [PMID: 18989748 DOI: 10.1007/s10545-008-0859-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2007] [Revised: 08/20/2008] [Accepted: 09/11/2008] [Indexed: 10/21/2022]
Abstract
Maple syrup urine disease (MSUD) is a very rare disorder of branched-chain amino acid metabolism. However, it is the most common inborn error of metabolism in the Philippines. We present a retrospective review of 21 patients diagnosed with MSUD between 1999 and 2004. The patients presented clinically between 2 and 14 days of life (mean 5 days) and the diagnosis of MSUD was established between 6 days and 11 months of age (mean 39 days). The classical burnt sugar odour was noted in the majority of patients (81%). The diagnosis of MSUD was initially based on clinical suspicion and confirmed biochemically by measurement of leucine/isoleucine levels by thin-layer chromatography. The acute management included removal of accumulated branched-chain amino acids by peritoneal dialysis in 62% of the patients. Mortality rate of this group of patients was 24% and follow-up rate was 87%. We compared this series with a previously reported series of 26 patients to determine whether diagnosis and the management of MSUD improved over the two periods. Four cases have been diagnosed early since 1992, the majority of whom had the classic form of MSUD with the onset of symptoms in the first two weeks of life. A small subset of patients with early nonspecific symptoms was diagnosed much later owing to a low-level clinical suspicion among clinicians. Overall, however, there appears to be a small but general trend towards earlier diagnosis, reduced mortality and long-term follow up in the later series. Although we are able to diagnose and manage MSUD in the Philippines, we recognize that the clinical outcome remains poor and is due mainly to late referral of cases and inadequate long-term management. In the Philippines, we recommend that all newborns who are considered to be septic, have feeding difficulties, fail to regain their birth weight or present with any other symptoms suggestive of MSUD be evaluated in the first instance by analysis of urine for ketones and if they are positive have blood collected and sent to our laboratory for leucine/isoleucine measurement.
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Affiliation(s)
- J Y Lee
- Metabolic Services, Genetic Health Services Victoria, Royal Children's Hospital, Melbourne, Australia
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Quental S, Martins E, Vilarinho L, Amorim A, João Prata M. Maple syrup urine disease due to a new large deletion at BCKDHA caused by non-homologous recombination. J Inherit Metab Dis 2008; 31 Suppl 2:S457-60. [PMID: 19085071 DOI: 10.1007/s10545-008-1046-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Revised: 10/22/2008] [Accepted: 10/24/2008] [Indexed: 11/24/2022]
Abstract
Maple syrup urine disease (MSUD) is a rare disorder of branched-chain amino acid (BCAA) metabolism caused by the defective function of branched-chain α-ketoacid dehydrogenase complex (BCKD). Many MSUD-causing mutations have already been described in genes that encode the complex (BCKDHA, BCKDHB and DBT), but up to now only four large deletions are known, all located in the DBT gene. In a previous study we identified a Portuguese MSUD patient with a homozygous deletion of exons 2, 3 and 4 at the BCKDHA gene; however, the corresponding breakpoints and, consequently, the exact deletion extension were not identified. Here, using long-range PCR and sequencing methodologies we were able to refine the characterization of this gross rearrangement. A genomic DNA loss of about 13.8 kb was detected, starting at intron 1 and ending at intron 4, thus encompassing exons 2, 3 and 4. Molecular characterization showed that the deletion junction contained a short sequence whose motif was CGGG. Since this motif is present in introns 1 and 4 of normal genomic DNA, we have hypothesized that non-homologous recombination was the mechanism underlying the identified large deletion, within which the CGGG could be derived either from intron 1 or from intron 4.
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Affiliation(s)
- S Quental
- IPATIMUP - Institute of Pathology and Molecular Immunology of University of Porto, Rua Dr Roberto Frias s/n, 4200-465, Porto, Portugal.
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Silao CLT, Padilla CD, Matsuo M. Early diagnosis of maple syrup urine disease using polymerase chain reaction-based mutation detection. Pediatr Int 2008; 50:312-4. [PMID: 18533943 DOI: 10.1111/j.1442-200x.2008.02610.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Maple syrup urine disease (MSUD) is an autosomal recessive disorder caused by defective activity of the branched-chain alpha-ketoacid dehydrogenase enzyme complex. Early diagnosis and management of MSUD are imperative for preventing permanent neurological impairments. In the Philippines, a 4.7 kb deletion in the dihydrolipoamide branched-chain transacylase E2 (DBT) gene has been commonly identified in MSUD patients. Polymerase chain reaction (PCR) amplification of a junction fragment between intron 10 and exon 11 has been used to detect this deletion. The purpose of the present paper was to use PCR-based mutation detection of the deletion mutation to diagnose MSUD in neonates in order to provide proper diagnosis and effective treatment. METHODS A region encompassing exon 11 and the junction fragment of the E2 (DBT) gene was PCR amplified from genomic DNA prepared from two neonates at risk for MSUD. RESULTS PCR amplification of both exon 11 and the junction fragment from one of the neonates demonstrated that this case was a heterozygous carrier of the deletion. Thus, normal feeding was started. For the other neonate, PCR amplification of the junction fragment was successful, whereas the region encompassing exon 11 was not amplified. This neonate was genotyped as homozygous for the deletion, and treatment for MSUD was provided immediately. CONCLUSION Examination of the deletion mutation in the E2 (DBT) gene facilitated early MSUD diagnosis and was beneficial for the determination of the proper course of treatment.
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Affiliation(s)
- Catherine Lynn T Silao
- Institute of Human Genetics, National Institutes of Health Philippines, Manila, Philippines
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Smith JR, Swift JA. Maple syrup urine disease hair reveals the importance of 18-methyleicosanoic acid in cuticular delamination. Micron 2005; 36:261-6. [PMID: 15725595 DOI: 10.1016/j.micron.2004.11.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2004] [Revised: 11/12/2004] [Accepted: 11/15/2004] [Indexed: 11/18/2022]
Abstract
18-Methyleicosanoic acid (18-MEA) is thought to be covalently bound to the outer surface of human hair and is a major component of the outer beta-layer of the cuticular cell membrane complex (CCMC). Cuticular delamination, whether this occurs between the outer beta- and delta-layers or within the plane of the beta-layer, results in a fresh layer of 18-MEA being exposed at the newly-revealed surface. Hair from patients with Maple Syrup Urine Disease (MSUD), however, does not contain 18-MEA and here, we report on the importance this unusual fatty acid in cuticular delamination. Hair fibres were collected from 10 patients with classic (type 1A) MSUD from a Mennonite community in Pennsylvania, USA. Included amongst these were hairs from dizygotic twins (A1 and A2), one of whom had MSUD, and the other did not; it was unknown at the beginning of the study which twin had MSUD. The outer surfaces were examined using atomic force microscopy (AFM) and transverse sections imaged using transmission electron microscopy (TEM). The newly revealed intercellular surface regions from twin A2 were found to be significantly rougher than those from twin A1. TEM studies showed the trilamellar CCMC to be continuous for twin A1, but possessed discontinuities of variable length (100-1000 nm) for twin A2. In contrast with other work, TEM showed no specific defects in the outer beta-layer. The outer cuticular surfaces for most MSUD patients showed a great abundance of residual endocuticle, although in other cases this was less pronounced. These differences may be explained by some residual activity of the branched-chain alpha-ketoacid (BCKD) dehydrogenase. Cuticular delamination in MSUD-hair probably still occurs within the general plane of the CCMC, although fracture through discontinuities of this layer results in zones of endocuticle being exposed at the new surface.
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Affiliation(s)
- James R Smith
- Scanning Probe Microscopy Laboratory, School of Pharmacy and Biomedical Sciences, University of Portsmouth, St. Michael's Building, White Swan Road, Portsmouth PO1 2DT, UK.
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