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Tangeraas T, Kristensen E, Mørkrid L, Elind E, Bliksrud YT, Eide L. Fasting and non-fasting plasma levels of monomethyl branched chain fatty acids: Implications for maple syrup urine disease. JIMD Rep 2023; 64:360-366. [PMID: 37701324 PMCID: PMC10494493 DOI: 10.1002/jmd2.12380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Revised: 06/21/2023] [Accepted: 06/26/2023] [Indexed: 09/14/2023] Open
Abstract
The branched-chain amino acids (BCAA) leucine, valine, and isoleucine provide precursors for monomethyl branched-chain fatty acids (BCFA). Established reference ranges for BCFAs are lacking. In maple syrup urine disease (MSUD), a rare inborn error of BCAA metabolism, the endogen production is impaired and MSUD patients are treated with a low protein (low BCAA) diet. The protein restriction may affect the dietary intake of BCFA, depending on the dietary choices made. Patients with MSUD are prescribed a more or less protein-restricted diet depending on the severity of the disease. The combination of a protein-restricted diet and subsequent impaired endogenous synthesis may render MSUD patients sensitive to BCFA deficiency, with yet unknown implications. To investigate the possibility of lower circulatory BCFA levels in MSUD that favors dietary BCFA supplementation, we first established fasting-state reference ranges for selected BCFAs and saturated/unsaturated fatty acids in plasma. Then, the effect of fasting on BCFA levels was evaluated by comparing the distribution in a fasting versus a non-fasting cohort. To test the hypothesis that BCFA deficiency could contribute to MSUD pathophysiology, we recruited patients with intermittent, intermediate, and classical form of MSUD and analyzed the corresponding BCFA z-scores. None of the BCFA species had |z-scores| > 2 relative to the reference range. Our findings do not support the requirement of BCFA supplementation in MSUD patients. The origin of BCFAs is discussed. Impaired capacity to synthesize BCFA do not manifest as reduced plasma levels in MSUD, suggesting that endogenous synthesis is dispensable for plasma levels.
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Affiliation(s)
- Trine Tangeraas
- Department of Newborn ScreeningOslo University HospitalOsloNorway
| | - Erle Kristensen
- Department of Medical BiochemistryOslo University HospitalOsloNorway
| | - Lars Mørkrid
- Department of Medical BiochemistryOslo University HospitalOsloNorway
- Department of Medical BiochemistryUniversity of OsloOsloNorway
| | - Elisabeth Elind
- Department of Newborn ScreeningOslo University HospitalOsloNorway
| | | | - Lars Eide
- Department of Medical BiochemistryOslo University HospitalOsloNorway
- Department of Medical BiochemistryUniversity of OsloOsloNorway
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Fang X, Zhu X, Feng Y, Bai Y, Zhao X, Liu N, Kong X. Genetic analysis by targeted next-generation sequencing and novel variation identification of maple syrup urine disease in Chinese Han population. Sci Rep 2021; 11:18939. [PMID: 34556729 PMCID: PMC8460745 DOI: 10.1038/s41598-021-98357-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 09/07/2021] [Indexed: 11/25/2022] Open
Abstract
Maple syrup urine disease (MSUD) is a rare autosomal recessive disorder that affects the degradation of branched chain amino acids (BCAAs). Only a few cases of MSUD have been documented in Mainland China. In this report, 8 patients (4 females and 4 males) with MSUD from 8 unrelated Chinese Han families were diagnosed at the age of 6 days to 4 months. All the coding regions and exon/intron boundaries of BCKDHA, BCDKHB, DBT and DLD genes were analyzed by targeted NGS in the 8 MSUD pedigrees. Targeted NGS revealed 2 pedigrees with MSUD Ia, 5 pedigrees with Ib, 1 pedigree with MSUD II. Totally, 13 variants were detected, including 2 variants (p.Ala216Val and p.Gly281Arg) in BCKDHA gene, 10 variants (p.Gly95Ala, p.Ser171Pro, p.Phe175Leu, p.Arg183Trp, p.Lys222Thr, p.Arg285Ter, p.Arg111Ter, p.S184Pfs*46, p.Arg170Cys, p.I160Ffs*25) in BCKDHB gene, 1 variant (p.Arg431Ter) in DBT gene. In addition, 4 previously unidentified variants (p.Gly281Arg in BCKDHA gene, p.Ser171Pro, p.Gly95Ala and p.Lys222Thr in BCKDHB gene) were identified. NGS plus Sanger sequencing detection is effective and accurate for gene diagnosis. Computational structural modeling indicated that these novel variations probably affect structural stability and considered as likely pathogenic variants.
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Affiliation(s)
- Xiaohua Fang
- Obstetrics and Gynecology Department, Genetics and Prenatal Diagnosis Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, People's Republic of China
| | - Xiaofan Zhu
- Obstetrics and Gynecology Department, Genetics and Prenatal Diagnosis Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, People's Republic of China
| | - Yin Feng
- Obstetrics and Gynecology Department, Genetics and Prenatal Diagnosis Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, People's Republic of China
| | - Ying Bai
- Obstetrics and Gynecology Department, Genetics and Prenatal Diagnosis Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, People's Republic of China
| | - Xuechao Zhao
- Obstetrics and Gynecology Department, Genetics and Prenatal Diagnosis Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, People's Republic of China
| | - Ning Liu
- Obstetrics and Gynecology Department, Genetics and Prenatal Diagnosis Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, People's Republic of China.
| | - Xiangdong Kong
- Obstetrics and Gynecology Department, Genetics and Prenatal Diagnosis Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, People's Republic of China.
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Tangeraas T, Sæves I, Klingenberg C, Jørgensen J, Kristensen E, Gunnarsdottir G, Hansen EV, Strand J, Lundman E, Ferdinandusse S, Salvador CL, Woldseth B, Bliksrud YT, Sagredo C, Olsen ØE, Berge MC, Trømborg AK, Ziegler A, Zhang JH, Sørgjerd LK, Ytre-Arne M, Hogner S, Løvoll SM, Kløvstad Olavsen MR, Navarrete D, Gaup HJ, Lilje R, Zetterström RH, Stray-Pedersen A, Rootwelt T, Rinaldo P, Rowe AD, Pettersen RD. Performance of Expanded Newborn Screening in Norway Supported by Post-Analytical Bioinformatics Tools and Rapid Second-Tier DNA Analyses. Int J Neonatal Screen 2020; 6:51. [PMID: 33123633 PMCID: PMC7570219 DOI: 10.3390/ijns6030051] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 06/22/2020] [Indexed: 12/12/2022] Open
Abstract
In 2012, the Norwegian newborn screening program (NBS) was expanded (eNBS) from screening for two diseases to that for 23 diseases (20 inborn errors of metabolism, IEMs) and again in 2018, to include a total of 25 conditions (21 IEMs). Between 1 March 2012 and 29 February 2020, 461,369 newborns were screened for 20 IEMs in addition to phenylketonuria (PKU). Excluding PKU, there were 75 true-positive (TP) (1:6151) and 107 (1:4311) false-positive IEM cases. Twenty-one percent of the TP cases were symptomatic at the time of the NBS results, but in two-thirds, the screening result directed the exact diagnosis. Eighty-two percent of the TP cases had good health outcomes, evaluated in 2020. The yearly positive predictive value was increased from 26% to 54% by the use of the Region 4 Stork post-analytical interpretive tool (R4S)/Collaborative Laboratory Integrated Reports 2.0 (CLIR), second-tier biochemical testing and genetic confirmation using DNA extracted from the original dried blood spots. The incidence of IEMs increased by 46% after eNBS was introduced, predominantly due to the finding of attenuated phenotypes. The next step is defining which newborns would truly benefit from screening at the milder end of the disease spectrum. This will require coordinated international collaboration, including proper case definitions and outcome studies.
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Affiliation(s)
- Trine Tangeraas
- Norwegian National Unit for Newborn Screening, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, 0424 Oslo, Norway; (I.S.); (J.J.); (E.K.); (J.S.); (E.L.); (C.S.); (Ø.E.O.); (M.C.B.); (A.K.T.); (A.Z.); (J.H.Z.); (L.K.S.); (M.Y.-A.); (S.H.); (S.M.L.); (M.R.K.O.); (D.N.); (H.J.G.); (A.S.-P.); (A.D.R.); (R.D.P.)
| | - Ingjerd Sæves
- Norwegian National Unit for Newborn Screening, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, 0424 Oslo, Norway; (I.S.); (J.J.); (E.K.); (J.S.); (E.L.); (C.S.); (Ø.E.O.); (M.C.B.); (A.K.T.); (A.Z.); (J.H.Z.); (L.K.S.); (M.Y.-A.); (S.H.); (S.M.L.); (M.R.K.O.); (D.N.); (H.J.G.); (A.S.-P.); (A.D.R.); (R.D.P.)
| | - Claus Klingenberg
- Department of Paediatrics, University Hospital of North Norway, 9019 Tromsø, Norway;
- Paediatric Research Group, Department of Clinical Medicine, UiT The Artic University of Norway, 9019 Tromsø, Norway
| | - Jens Jørgensen
- Norwegian National Unit for Newborn Screening, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, 0424 Oslo, Norway; (I.S.); (J.J.); (E.K.); (J.S.); (E.L.); (C.S.); (Ø.E.O.); (M.C.B.); (A.K.T.); (A.Z.); (J.H.Z.); (L.K.S.); (M.Y.-A.); (S.H.); (S.M.L.); (M.R.K.O.); (D.N.); (H.J.G.); (A.S.-P.); (A.D.R.); (R.D.P.)
| | - Erle Kristensen
- Norwegian National Unit for Newborn Screening, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, 0424 Oslo, Norway; (I.S.); (J.J.); (E.K.); (J.S.); (E.L.); (C.S.); (Ø.E.O.); (M.C.B.); (A.K.T.); (A.Z.); (J.H.Z.); (L.K.S.); (M.Y.-A.); (S.H.); (S.M.L.); (M.R.K.O.); (D.N.); (H.J.G.); (A.S.-P.); (A.D.R.); (R.D.P.)
- Paediatric Research Group, Department of Clinical Medicine, UiT The Artic University of Norway, 9019 Tromsø, Norway
| | - Gunnþórunn Gunnarsdottir
- Department of Paediatrics, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, 0424 Oslo, Norway; (G.G.); (R.L.); (T.R.)
| | | | - Janne Strand
- Norwegian National Unit for Newborn Screening, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, 0424 Oslo, Norway; (I.S.); (J.J.); (E.K.); (J.S.); (E.L.); (C.S.); (Ø.E.O.); (M.C.B.); (A.K.T.); (A.Z.); (J.H.Z.); (L.K.S.); (M.Y.-A.); (S.H.); (S.M.L.); (M.R.K.O.); (D.N.); (H.J.G.); (A.S.-P.); (A.D.R.); (R.D.P.)
| | - Emma Lundman
- Norwegian National Unit for Newborn Screening, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, 0424 Oslo, Norway; (I.S.); (J.J.); (E.K.); (J.S.); (E.L.); (C.S.); (Ø.E.O.); (M.C.B.); (A.K.T.); (A.Z.); (J.H.Z.); (L.K.S.); (M.Y.-A.); (S.H.); (S.M.L.); (M.R.K.O.); (D.N.); (H.J.G.); (A.S.-P.); (A.D.R.); (R.D.P.)
| | - Sacha Ferdinandusse
- Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, Amsterdam University Medical Centers, University of Amsterdam, AZ 1105 Amsterdam, The Netherlands;
| | - Cathrin Lytomt Salvador
- Norwegian National Unit for Diagnostics of Congenital Metabolic Disorders, Department of Medical Biochemistry, Oslo University Hospital, 0424 Oslo, Norway; (C.L.S.); (B.W.); (Y.T.B.)
| | - Berit Woldseth
- Norwegian National Unit for Diagnostics of Congenital Metabolic Disorders, Department of Medical Biochemistry, Oslo University Hospital, 0424 Oslo, Norway; (C.L.S.); (B.W.); (Y.T.B.)
| | - Yngve T Bliksrud
- Norwegian National Unit for Diagnostics of Congenital Metabolic Disorders, Department of Medical Biochemistry, Oslo University Hospital, 0424 Oslo, Norway; (C.L.S.); (B.W.); (Y.T.B.)
| | - Carlos Sagredo
- Norwegian National Unit for Newborn Screening, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, 0424 Oslo, Norway; (I.S.); (J.J.); (E.K.); (J.S.); (E.L.); (C.S.); (Ø.E.O.); (M.C.B.); (A.K.T.); (A.Z.); (J.H.Z.); (L.K.S.); (M.Y.-A.); (S.H.); (S.M.L.); (M.R.K.O.); (D.N.); (H.J.G.); (A.S.-P.); (A.D.R.); (R.D.P.)
| | - Øyvind E Olsen
- Norwegian National Unit for Newborn Screening, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, 0424 Oslo, Norway; (I.S.); (J.J.); (E.K.); (J.S.); (E.L.); (C.S.); (Ø.E.O.); (M.C.B.); (A.K.T.); (A.Z.); (J.H.Z.); (L.K.S.); (M.Y.-A.); (S.H.); (S.M.L.); (M.R.K.O.); (D.N.); (H.J.G.); (A.S.-P.); (A.D.R.); (R.D.P.)
| | - Mona C Berge
- Norwegian National Unit for Newborn Screening, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, 0424 Oslo, Norway; (I.S.); (J.J.); (E.K.); (J.S.); (E.L.); (C.S.); (Ø.E.O.); (M.C.B.); (A.K.T.); (A.Z.); (J.H.Z.); (L.K.S.); (M.Y.-A.); (S.H.); (S.M.L.); (M.R.K.O.); (D.N.); (H.J.G.); (A.S.-P.); (A.D.R.); (R.D.P.)
| | - Anette Kjoshagen Trømborg
- Norwegian National Unit for Newborn Screening, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, 0424 Oslo, Norway; (I.S.); (J.J.); (E.K.); (J.S.); (E.L.); (C.S.); (Ø.E.O.); (M.C.B.); (A.K.T.); (A.Z.); (J.H.Z.); (L.K.S.); (M.Y.-A.); (S.H.); (S.M.L.); (M.R.K.O.); (D.N.); (H.J.G.); (A.S.-P.); (A.D.R.); (R.D.P.)
| | - Anders Ziegler
- Norwegian National Unit for Newborn Screening, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, 0424 Oslo, Norway; (I.S.); (J.J.); (E.K.); (J.S.); (E.L.); (C.S.); (Ø.E.O.); (M.C.B.); (A.K.T.); (A.Z.); (J.H.Z.); (L.K.S.); (M.Y.-A.); (S.H.); (S.M.L.); (M.R.K.O.); (D.N.); (H.J.G.); (A.S.-P.); (A.D.R.); (R.D.P.)
| | - Jin Hui Zhang
- Norwegian National Unit for Newborn Screening, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, 0424 Oslo, Norway; (I.S.); (J.J.); (E.K.); (J.S.); (E.L.); (C.S.); (Ø.E.O.); (M.C.B.); (A.K.T.); (A.Z.); (J.H.Z.); (L.K.S.); (M.Y.-A.); (S.H.); (S.M.L.); (M.R.K.O.); (D.N.); (H.J.G.); (A.S.-P.); (A.D.R.); (R.D.P.)
| | - Linda Karlsen Sørgjerd
- Norwegian National Unit for Newborn Screening, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, 0424 Oslo, Norway; (I.S.); (J.J.); (E.K.); (J.S.); (E.L.); (C.S.); (Ø.E.O.); (M.C.B.); (A.K.T.); (A.Z.); (J.H.Z.); (L.K.S.); (M.Y.-A.); (S.H.); (S.M.L.); (M.R.K.O.); (D.N.); (H.J.G.); (A.S.-P.); (A.D.R.); (R.D.P.)
| | - Mari Ytre-Arne
- Norwegian National Unit for Newborn Screening, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, 0424 Oslo, Norway; (I.S.); (J.J.); (E.K.); (J.S.); (E.L.); (C.S.); (Ø.E.O.); (M.C.B.); (A.K.T.); (A.Z.); (J.H.Z.); (L.K.S.); (M.Y.-A.); (S.H.); (S.M.L.); (M.R.K.O.); (D.N.); (H.J.G.); (A.S.-P.); (A.D.R.); (R.D.P.)
| | - Silje Hogner
- Norwegian National Unit for Newborn Screening, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, 0424 Oslo, Norway; (I.S.); (J.J.); (E.K.); (J.S.); (E.L.); (C.S.); (Ø.E.O.); (M.C.B.); (A.K.T.); (A.Z.); (J.H.Z.); (L.K.S.); (M.Y.-A.); (S.H.); (S.M.L.); (M.R.K.O.); (D.N.); (H.J.G.); (A.S.-P.); (A.D.R.); (R.D.P.)
| | - Siv M Løvoll
- Norwegian National Unit for Newborn Screening, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, 0424 Oslo, Norway; (I.S.); (J.J.); (E.K.); (J.S.); (E.L.); (C.S.); (Ø.E.O.); (M.C.B.); (A.K.T.); (A.Z.); (J.H.Z.); (L.K.S.); (M.Y.-A.); (S.H.); (S.M.L.); (M.R.K.O.); (D.N.); (H.J.G.); (A.S.-P.); (A.D.R.); (R.D.P.)
| | - Mette R Kløvstad Olavsen
- Norwegian National Unit for Newborn Screening, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, 0424 Oslo, Norway; (I.S.); (J.J.); (E.K.); (J.S.); (E.L.); (C.S.); (Ø.E.O.); (M.C.B.); (A.K.T.); (A.Z.); (J.H.Z.); (L.K.S.); (M.Y.-A.); (S.H.); (S.M.L.); (M.R.K.O.); (D.N.); (H.J.G.); (A.S.-P.); (A.D.R.); (R.D.P.)
| | - Dionne Navarrete
- Norwegian National Unit for Newborn Screening, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, 0424 Oslo, Norway; (I.S.); (J.J.); (E.K.); (J.S.); (E.L.); (C.S.); (Ø.E.O.); (M.C.B.); (A.K.T.); (A.Z.); (J.H.Z.); (L.K.S.); (M.Y.-A.); (S.H.); (S.M.L.); (M.R.K.O.); (D.N.); (H.J.G.); (A.S.-P.); (A.D.R.); (R.D.P.)
| | - Hege J Gaup
- Norwegian National Unit for Newborn Screening, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, 0424 Oslo, Norway; (I.S.); (J.J.); (E.K.); (J.S.); (E.L.); (C.S.); (Ø.E.O.); (M.C.B.); (A.K.T.); (A.Z.); (J.H.Z.); (L.K.S.); (M.Y.-A.); (S.H.); (S.M.L.); (M.R.K.O.); (D.N.); (H.J.G.); (A.S.-P.); (A.D.R.); (R.D.P.)
| | - Rina Lilje
- Department of Paediatrics, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, 0424 Oslo, Norway; (G.G.); (R.L.); (T.R.)
| | - Rolf H Zetterström
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Solna, Sweden, Department of Molecular Medicine and Surgery, Karolinska Institutet, SE-171 76 Stockholm, Sweden;
| | - Asbjørg Stray-Pedersen
- Norwegian National Unit for Newborn Screening, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, 0424 Oslo, Norway; (I.S.); (J.J.); (E.K.); (J.S.); (E.L.); (C.S.); (Ø.E.O.); (M.C.B.); (A.K.T.); (A.Z.); (J.H.Z.); (L.K.S.); (M.Y.-A.); (S.H.); (S.M.L.); (M.R.K.O.); (D.N.); (H.J.G.); (A.S.-P.); (A.D.R.); (R.D.P.)
| | - Terje Rootwelt
- Department of Paediatrics, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, 0424 Oslo, Norway; (G.G.); (R.L.); (T.R.)
- Institute of Clinical Medicine, University of Oslo, 0318 Oslo, Norway
| | - Piero Rinaldo
- Biochemical Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, NY 55902, USA;
| | - Alexander D Rowe
- Norwegian National Unit for Newborn Screening, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, 0424 Oslo, Norway; (I.S.); (J.J.); (E.K.); (J.S.); (E.L.); (C.S.); (Ø.E.O.); (M.C.B.); (A.K.T.); (A.Z.); (J.H.Z.); (L.K.S.); (M.Y.-A.); (S.H.); (S.M.L.); (M.R.K.O.); (D.N.); (H.J.G.); (A.S.-P.); (A.D.R.); (R.D.P.)
| | - Rolf D Pettersen
- Norwegian National Unit for Newborn Screening, Division of Paediatric and Adolescent Medicine, Oslo University Hospital, 0424 Oslo, Norway; (I.S.); (J.J.); (E.K.); (J.S.); (E.L.); (C.S.); (Ø.E.O.); (M.C.B.); (A.K.T.); (A.Z.); (J.H.Z.); (L.K.S.); (M.Y.-A.); (S.H.); (S.M.L.); (M.R.K.O.); (D.N.); (H.J.G.); (A.S.-P.); (A.D.R.); (R.D.P.)
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Han B, Han B, Guo B, Liu Y, Cao Z. Two novel mutations in the BCKDHB gene that cause maple syrup urine disease. Pediatr Neonatol 2018; 59:515-519. [PMID: 29366676 DOI: 10.1016/j.pedneo.2018.01.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Revised: 09/08/2017] [Accepted: 01/02/2018] [Indexed: 10/18/2022] Open
Abstract
BACKGROUND Maple syrup urine disease (MSUD) is a rare metabolic disorder of autosomal recessive inheritance caused by decreased activity of branched-chain α-ketoacid dehydrogenase complex (BCKD). Mutations in the three genes (BCKDHA, BCKDHB and DBT) are associated with MSUD. Here, we describe the presenting symptoms, clinical course and gene mutation analysis of a Chinese boy with MSUD. METHODS Plasma amino acid analysis was performed by tandem mass spectrometry and the levels of organic acids in urine were measured with gas chromatography-mass spectrometry. The BCKDHB gene was sequenced by Sanger method. Furthermore, the significance of the novel mutations was predicted by Polyphen and Mutationtaster. After diagnosis, the patient was fed with protein-restricted diet to reduce intake of BCAA and was treated with l-carnitine. Metabolic parameters, clinical presentation and mental development were followed up. RESULTS The patient was diagnosed as MSUD. Two novel BCKDHB mutations (c.523 T > C and c.478-25_552del100) were identified. In silico analysis predicted that the two mutations were "disease causing". The boy tolerated the treatment well and had symptomatic improvement. He presented with mild hypotonia and had nearly normal DQ scores at the age of 10 months. The two novel mutations resulted in the clinical manifestations of MSUD. Our results may reflect the heterogeneity of the pathogenic variants found in patients with MSUD.
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Affiliation(s)
- Bingjuan Han
- Jinan Maternal and Child Care Hospital, Jinan, 250001, Shandong Province, China
| | - Bingchao Han
- Jinan Maternal and Child Care Hospital, Jinan, 250001, Shandong Province, China
| | - Bin Guo
- Jinan Maternal and Child Care Hospital, Jinan, 250001, Shandong Province, China
| | - Yingxia Liu
- Jinan Maternal and Child Care Hospital, Jinan, 250001, Shandong Province, China; Department of Immunology, Nanjing Medical University, Nanjing, 21166, Jiangsu Province, China.
| | - Zhiyang Cao
- Nanjing Jiangning Hospital, Affiliated to Nanjing Medical University, Nanjing 211100, Jiangsu Province, China.
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Strand JM, Skinnes R, Scheffler K, Rootvelt T, Woldseth B, Bjørås M, Eide L. Genome instability in Maple Syrup Urine Disease correlates with impaired mitochondrial biogenesis. Metabolism 2014; 63:1063-70. [PMID: 24928662 DOI: 10.1016/j.metabol.2014.05.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 04/09/2014] [Accepted: 05/04/2014] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The mitochondrial branched-chain ketoacid dehydrogenase (BCKD) catalyzes the degradation of branched-chain amino acids (BCAA), which have been shown to induce oxidative stress. Maple Syrup Urine Disease (MSUD) is caused by impaired activity of BCKD, suggesting that oxidative stress and resulting DNA damage could contribute to pathology. We evaluated the potential effect of BCKD deficiency on genome integrity and mitochondrial function as a downstream target. METHODS Primary fibroblasts from MSUD patients and controls were either cultivated under normal conditions or exposed to metabolic or oxidative stress. DNA was analyzed for damage and mitochondrial function was evaluated by gene expression analyses, functional assays and immunofluorescent methods. RESULTS Patient fibroblasts accumulated damage in mitochondrial DNA (mtDNA) and nuclear DNA, with a corresponding reduction in mitochondrial transcription, mtDNA copy number and pyruvate dehydrogenase. We found no evidence of increased level of reactive oxygen species (ROS) in patient fibroblasts under normal conditions, suggesting that the genotoxic effect is ascribed to accumulating metabolites. CONCLUSIONS Impaired BCKD activity as in MSUD, results in accumulation of DNA damage and corresponding mitochondrial dysfunction.
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Affiliation(s)
- Janne M Strand
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway; Department of Microbiology, University of Oslo, Oslo University Hospital, Oslo, Norway
| | - Ragnhild Skinnes
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
| | - Katja Scheffler
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway; Department of Microbiology, University of Oslo, Oslo University Hospital, Oslo, Norway
| | - Terje Rootvelt
- Women and Children's Division, Oslo University Hospital, Oslo, Norway
| | - Berit Woldseth
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
| | - Magnar Bjørås
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway; Department of Microbiology, University of Oslo, Oslo University Hospital, Oslo, Norway
| | - Lars Eide
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway.
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Yang N, Han L, Gu X, Ye J, Qiu W, Zhang H, Gong Z, Zhang Y. Analysis of gene mutations in Chinese patients with maple syrup urine disease. Mol Genet Metab 2012; 106:412-8. [PMID: 22727569 DOI: 10.1016/j.ymgme.2012.05.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Accepted: 05/29/2012] [Indexed: 11/19/2022]
Abstract
OBJECTIVE Maple syrup urine disease (MSUD) is predominantly caused by mutations in the BCKDHA, BCKDHB and DBT genes, which encode for the E1α, E1β and E2 subunits of the branched-chain α-keto acid dehydrogenase complex, respectively. The aim of this study was to screen DNA samples from 16 Chinese MSUD patients and assess a potential correlation between genotype and phenotype. METHODS BCKDHA, BCKDHB and DBT genes were analyzed by polymerase chain reaction (PCR) and direct sequencing. Segments bearing novel mutations were identified by PCR-restriction fragment length polymorphism (PCR-RFLP) analysis. RESULTS Within the variant alleles, 28 mutations (28/32, 87.5%), were detected in 15 patients, while one patient displayed no mutations. Mutations were comprised of 20 different: 6 BCKDHA gene mutations in 4 cases, 10 BCKDHB gene mutations in 8 cases and 4 DBT gene mutations in 3 cases. From these, 14 were novel, which included 3 mutations in the BCKDHA gene, 7 in the BCKDHB gene and 4 in the DBT gene. Only two patients with mutations in the BCKDHB and DBT genes were thiamine-responsive and presented a better clinical outcome. CONCLUSION We identified 20 different mutations within the BCKDHA, BCKDHB and DBT genes among 16 Chinese MSUD patients, including 14 novel mutations. The majority were non-responsive to thiamine, associating with a worse clinical outcome. Our data provide the basis for further genotype-phenotype correlation studies in these patients, which will be beneficial for early diagnosis and in directing the approach to clinical intervention.
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Affiliation(s)
- Nan Yang
- Department of Pediatric Endocrinology, Genetic and Metabolic Disease, Shanghai Institute of Pediatric Research, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China
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Brunetti-Pierri N, Lanpher B, Erez A, Ananieva EA, Islam M, Marini JC, Sun Q, Yu C, Hegde M, Li J, Wynn RM, Chuang DT, Hutson S, Lee B. Phenylbutyrate therapy for maple syrup urine disease. Hum Mol Genet 2010; 20:631-40. [PMID: 21098507 DOI: 10.1093/hmg/ddq507] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Therapy with sodium phenylacetate/benzoate or sodium phenylbutyrate in urea cycle disorder patients has been associated with a selective reduction in branched-chain amino acids (BCAA) in spite of adequate dietary protein intake. Based on this clinical observation, we investigated the potential of phenylbutyrate treatment to lower BCAA and their corresponding α-keto acids (BCKA) in patients with classic and variant late-onset forms of maple syrup urine disease (MSUD). We also performed in vitro and in vivo experiments to elucidate the mechanism for this effect. We found that BCAA and BCKA are both significantly reduced following phenylbutyrate therapy in control subjects and in patients with late-onset, intermediate MSUD. In vitro treatment with phenylbutyrate of control fibroblasts and lymphoblasts resulted in an increase in the residual enzyme activity, while treatment of MSUD cells resulted in the variable response which did not simply predict the biochemical response in the patients. In vivo phenylbutyrate increases the proportion of active hepatic enzyme and unphosphorylated form over the inactive phosphorylated form of the E1α subunit of the branched-chain α-keto acid dehydrogenase complex (BCKDC). Using recombinant enzymes, we show that phenylbutyrate prevents phosphorylation of E1α by inhibition of the BCKDC kinase to activate BCKDC overall activity, providing a molecular explanation for the effect of phenylbutyrate in a subset of MSUD patients. Phenylbutyrate treatment may be a valuable treatment for reducing the plasma levels of neurotoxic BCAA and their corresponding BCKA in a subset of MSUD patients and studies of its long-term efficacy are indicated.
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Affiliation(s)
- Nicola Brunetti-Pierri
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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