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Collado MS, Armstrong AJ, Olson M, Hoang SA, Day N, Summar M, Chapman KA, Reardon J, Figler RA, Wamhoff BR. Biochemical and anaplerotic applications of in vitro models of propionic acidemia and methylmalonic acidemia using patient-derived primary hepatocytes. Mol Genet Metab 2020; 130:183-196. [PMID: 32451238 PMCID: PMC7337260 DOI: 10.1016/j.ymgme.2020.05.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 04/30/2020] [Accepted: 05/01/2020] [Indexed: 12/12/2022]
Abstract
Propionic acidemia (PA) and methylmalonic acidemia (MMA) are autosomal recessive disorders of propionyl-CoA (P-CoA) catabolism, which are caused by a deficiency in the enzyme propionyl-CoA carboxylase or the enzyme methylmalonyl-CoA (MM-CoA) mutase, respectively. The functional consequence of PA or MMA is the inability to catabolize P-CoA to MM-CoA or MM-CoA to succinyl-CoA, resulting in the accumulation of P-CoA and other metabolic intermediates, such as propionylcarnitine (C3), 3-hydroxypropionic acid, methylcitric acid (MCA), and methylmalonic acid (only in MMA). P-CoA and its metabolic intermediates, at high concentrations found in PA and MMA, inhibit enzymes in the first steps of the urea cycle as well as enzymes in the tricarboxylic acid (TCA) cycle, causing a reduction in mitochondrial energy production. We previously showed that metabolic defects of PA could be recapitulated using PA patient-derived primary hepatocytes in a novel organotypic system. Here, we sought to investigate whether treatment of normal human primary hepatocytes with propionate would recapitulate some of the biochemical features of PA and MMA in the same platform. We found that high levels of propionate resulted in high levels of intracellular P-CoA in normal hepatocytes. Analysis of TCA cycle intermediates by GC-MS/MS indicated that propionate may inhibit enzymes of the TCA cycle as shown in PA, but is also incorporated in the TCA cycle, which does not occur in PA. To better recapitulate the disease phenotype, we obtained hepatocytes derived from livers of PA and MMA patients. We characterized the PA and MMA donors by measuring key proximal biomarkers, including P-CoA, MM-CoA, as well as clinical biomarkers propionylcarnitine-to-acetylcarnitine ratios (C3/C2), MCA, and methylmalonic acid. Additionally, we used isotopically-labeled amino acids to investigate the contribution of relevant amino acids to production of P-CoA in models of metabolic stability or acute metabolic crisis. As observed clinically, we demonstrated that the isoleucine and valine catabolism pathways are the greatest sources of P-CoA in PA and MMA donor cells and that each donor showed differential sensitivity to isoleucine and valine. We also studied the effects of disodium citrate, an anaplerotic therapy, which resulted in a significant increase in the absolute concentration of TCA cycle intermediates, which is in agreement with the benefit observed clinically. Our human cell-based PA and MMA disease models can inform preclinical drug discovery and development where mouse models of these diseases are inaccurate, particularly in well-described species differences in branched-chain amino acid catabolism.
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Affiliation(s)
- M Sol Collado
- HemoShear Therapeutics, LLC, Charlottesville, VA, USA
| | | | - Matthew Olson
- HemoShear Therapeutics, LLC, Charlottesville, VA, USA
| | | | - Nathan Day
- HemoShear Therapeutics, LLC, Charlottesville, VA, USA
| | - Marshall Summar
- Children's National Rare Disease Institute, Washington, DC, USA
| | | | - John Reardon
- HemoShear Therapeutics, LLC, Charlottesville, VA, USA
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Kang L, Liu Y, Shen M, Liu Y, He R, Song J, Jin Y, Li M, Zhang Y, Dong H, Liu X, Yan H, Qin J, Zheng H, Chen Y, Li D, Wei H, Zhang H, Sun L, Zhu Z, Liang D, Yang Y. A study on a cohort of 301 Chinese patients with isolated methylmalonic acidemia. J Inherit Metab Dis 2020; 43:409-423. [PMID: 31622506 DOI: 10.1002/jimd.12183] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 09/28/2019] [Accepted: 10/16/2019] [Indexed: 01/03/2023]
Abstract
Methylmalonic acidemia (MMA) is the most common organic acidemia in China. This study aimed to characterise the genotypic and phenotypic variabilities, and the molecular epidemiology of Chinese patients with isolated MMA. Patients (n = 301) with isolated MMA were diagnosed by clinical examination, biochemical assays, and genetic analysis. Fifty-eight patients (19.3%) were detected by newborn screening and 243 patients (80.7%) were clinically diagnosed after onset. Clinical onset ranged from the age of 3 days to 23 years (mean age = 1.01 ± 0.15 years). Among 234 MMA patients whose detailed clinical data were available, 170 (72.6%) had early onset disease (before the age of 1 year), and 64 (27.4%) had late-onset disease. The 234 MMA patients manifested with neuropsychiatric impairment (65.4%), haematological abnormality (31.6%), renal damage (8.5%), and metabolic crises (67.1%). Haematological abnormality was significantly more common in early-onset patients than that in late-onset patients. The incidence of metabolic crises was significantly high (P < 0.001) in patients with mut type than those with other types of isolated MMA. Variations (n = 122) were identified in MMUT, MMAA, MMAB, MMADHC, SUCLG1, and SUCLA2, of which 45 were novel. c.729_730insTT was the most frequent MMUT mutation, with a significantly higher frequency in our patients than that in 151 reported European patients. The frequency of c.914T>C in MMUT in our cohort was also higher than that in 151 European patients. MMUT mutations c.729_730insTT and c.914T>C are specific for the Chinese population. Our study expanded the spectrum of phenotypes and genotypes in isolated MMA.
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Affiliation(s)
- Lulu Kang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Yupeng Liu
- Department of Pediatrics, People's Hospital of Peking University, Beijing, China
| | - Ming Shen
- Translational Medicine Laboratory, Chinese People's Liberation Army General Hospital, Beijing, China
| | - Yi Liu
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Ruxuan He
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Jinqing Song
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Ying Jin
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Mengqiu Li
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Yao Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Hui Dong
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Xueqin Liu
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Hui Yan
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Jiong Qin
- Department of Pediatrics, People's Hospital of Peking University, Beijing, China
| | - Hong Zheng
- Department of Pediatrics, First Affiliated Hospital of Henan University of Traditional Chinese Medicine, Zhengzhou, China
| | - Yongxing Chen
- Department of Endocrinology and Genetic, Henan Children's Hospital, Zhengzhou, China
| | - Dongxiao Li
- Department of Endocrinology and Genetic, Henan Children's Hospital, Zhengzhou, China
| | - Haiyan Wei
- Department of Endocrinology and Genetic, Henan Children's Hospital, Zhengzhou, China
| | - Huifeng Zhang
- Department of Pediatrics, Hebei Medical University Second Hospital, Shijiazhuang, China
| | - Liying Sun
- Center of Liver Transplantation, Beijing Friendship Hospital, Beijing, China
| | - Zhijun Zhu
- Center of Liver Transplantation, Beijing Friendship Hospital, Beijing, China
| | - Desheng Liang
- Center of Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Yanling Yang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
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3
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Keyfi F, Abbaszadegan MR, Sankian M, Rolfs A, Orolicki S, Pournasrollah M, Alijanpour M, Varasteh A. Mutation analysis of genes related to methylmalonic acidemia: identification of eight novel mutations. Mol Biol Rep 2019; 46:271-285. [PMID: 30712249 DOI: 10.1007/s11033-018-4469-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 11/02/2018] [Indexed: 11/28/2022]
Abstract
Methylmalonic acidemia (MMA), an inherited metabolic disease, results from genetic defects in methylmalonyl-CoA mutase or any of the proteins involved in adenosylcobalamin synthesis. This enzyme is classified into several complementation groups and genotypic classes. In this work we explain the biochemical, structural and genetic analysis of 25 MMA patients, from Iran. The diagnosis was established by the measurement of propionylcarnitine in blood using tandem mass spectrometry and confirmed using a gas chromatography-flame ionization detector. Using clinical, biochemical, structural and molecular analyses we identified 15 mut MMA, three cblA, one cblB, and four cblC-deficient patients. Among mutations identified in the MUT gene (MUT) only one, the c.1874A>C (p.D625A) variant, is likely a mut- mutation. The remaining mutations are probably mut0. Here, we present the first molecular analysis of MMA in Iranian patients and have identified eight novel mutations. Four novel mutations (p.D625A, p.R326G, p.V157F, p.F379L) were seen exclusively in patients from northern Iran. One novel splice site mutation (c.2125-3C>G) in MUT and two novel mutation (p.N225M and p.A99P) in the MMAA gene were associated with patients from eastern Iran. The rs184829210 SNP was recognized only in patients with the novel c.958G>A (p.A320T) mutation. This study confirms pathogenesis of deficient enzyme activity in MUT, MMAA, MMAB, and MMACHC as previous observations. These results could act as a basis for the performance of pharmacological therapies for increasing the activity of proteins derived from these mutations.
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Affiliation(s)
- Fatemeh Keyfi
- Department of Medical Laboratory Sciences, Varastegan Institute for Medical Sciences, Mashhad, Iran.,Division of Metabolic disorders, Pardis Clinical and Genetic Laboratory, Mashhad, Iran.,Immunology Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohammad R Abbaszadegan
- Division of Human Genetics, Immunology Research Center, Avicenna Research Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mojtaba Sankian
- Immunology Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Arndt Rolfs
- Albrecht Kossel Institute for Neuroregeneration, University of Rostock, Rostock, Germany.,Chief Medical Director, Centogene AG, Rostock, Germany
| | | | - Mohammad Pournasrollah
- Non-contagious pediatric disease Research Center, Babol University of Medical Sciences, Babol, Iran
| | - Morteza Alijanpour
- Non-contagious pediatric disease Research Center, Babol University of Medical Sciences, Babol, Iran
| | - Abdolreza Varasteh
- Department of Medical Laboratory Sciences, Varastegan Institute for Medical Sciences, Mashhad, Iran. .,Division of Metabolic disorders, Pardis Clinical and Genetic Laboratory, Mashhad, Iran. .,Allergy Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
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4
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Kumari C, Kapoor S, Varughese B, Pollipali SK, Ramji S. Mutation Analyses in Selected Exons of the MUT Gene in Indian Patients with Methylmalonic Acidemia. Indian J Clin Biochem 2016; 32:266-274. [PMID: 28811685 DOI: 10.1007/s12291-016-0600-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 07/29/2016] [Indexed: 01/27/2023]
Abstract
Deficiency or diminished activity of a cobalamin dependent enzyme methylmalonyl-CoA mutase causes inborn error of metabolism called methylmalonic acidemia (MMA). In this study we elucidated the spectrum of mutations in 21 Indian mut MMA patients by direct sequencing. Sequence analysis identified a total of 70 mutations in exon 2, 9, 11 and 12 of MUT gene. Out of which 26 mutations were predicted to be deleterious and rest were benign. The 23 novel mutations consist of four nonsense mutations (p.N6*, p.G539*, p.E609* and p.I671*), twelve missense mutations (p.K128I, p.N547T, p.D554Y, p.A558T, p.R559P, p.A631T, p.I647T, p.E656D, p.V657E, p.Q660H, p.K679N, and p.G696Y) and seven frame shift mutations (c.375_376insA, c.1642delA, c.1655delC, c.1825_1826insT, c.1957delGA, c.2014delA and c.2062_2063insGA). All of them are point mutations or micro rearrangements. Three of these mutations (p.K621N, p.G648D, p.G630E) have been previously reported; all of them are missense mutations. The mutations are distributed throughout the exon 2, 9, 11 and 12, 38.4 % mutation are located in exon 12.
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Affiliation(s)
- Chandrawati Kumari
- Pediatrics Genetic and Research Laboratory, Department of Pediatrics, Maulana Azad Medical College, New Medical Block, Opposite Old Casualty, Lok Nayak Hospital, New Delhi, 110002 India
| | - Seema Kapoor
- Pediatrics Genetic and Research Laboratory, Department of Pediatrics, Maulana Azad Medical College, New Medical Block, Opposite Old Casualty, Lok Nayak Hospital, New Delhi, 110002 India
| | - Bijo Varughese
- Pediatrics Genetic and Research Laboratory, Department of Pediatrics, Maulana Azad Medical College, New Medical Block, Opposite Old Casualty, Lok Nayak Hospital, New Delhi, 110002 India
| | - Sunil Kumar Pollipali
- Pediatrics Genetic and Research Laboratory, Department of Pediatrics, Maulana Azad Medical College, New Medical Block, Opposite Old Casualty, Lok Nayak Hospital, New Delhi, 110002 India
| | - Siddarth Ramji
- Department of Neonatology, Maulana Azad Medical College, New Delhi, 110002 India
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5
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Forny P, Schnellmann AS, Buerer C, Lutz S, Fowler B, Froese DS, Baumgartner MR. Molecular Genetic Characterization of 151Mut-Type Methylmalonic Aciduria Patients and Identification of 41 Novel Mutations inMUT. Hum Mutat 2016; 37:745-54. [DOI: 10.1002/humu.23013] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 05/05/2016] [Indexed: 11/09/2022]
Affiliation(s)
- Patrick Forny
- Division of Metabolism and Children's Research Center; University Children's Hospital; Zurich CH-8032 Switzerland
- radiz - Rare Disease Initiative Zurich; Clinical Research Priority Program for Rare Diseases; University of Zurich; Zurich Switzerland
- Zurich Center for Integrative Human Physiology; University of Zurich; Zurich Switzerland
| | - Anne-Sophie Schnellmann
- Division of Metabolism and Children's Research Center; University Children's Hospital; Zurich CH-8032 Switzerland
| | - Celine Buerer
- Division of Metabolism and Children's Research Center; University Children's Hospital; Zurich CH-8032 Switzerland
| | - Seraina Lutz
- Division of Metabolism and Children's Research Center; University Children's Hospital; Zurich CH-8032 Switzerland
| | - Brian Fowler
- Division of Metabolism and Children's Research Center; University Children's Hospital; Zurich CH-8032 Switzerland
| | - D. Sean Froese
- Division of Metabolism and Children's Research Center; University Children's Hospital; Zurich CH-8032 Switzerland
- radiz - Rare Disease Initiative Zurich; Clinical Research Priority Program for Rare Diseases; University of Zurich; Zurich Switzerland
| | - Matthias R. Baumgartner
- Division of Metabolism and Children's Research Center; University Children's Hospital; Zurich CH-8032 Switzerland
- radiz - Rare Disease Initiative Zurich; Clinical Research Priority Program for Rare Diseases; University of Zurich; Zurich Switzerland
- Zurich Center for Integrative Human Physiology; University of Zurich; Zurich Switzerland
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6
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Wong ESY, McIntyre C, Peters HL, Ranieri E, Anson DS, Fletcher JM. Correction of methylmalonic aciduria in vivo using a codon-optimized lentiviral vector. Hum Gene Ther 2014; 25:529-38. [PMID: 24568291 DOI: 10.1089/hum.2013.111] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Methylmalonic aciduria is a rare disorder of organic acid metabolism with limited therapeutic options, resulting in high morbidity and mortality. Positive results from combined liver/kidney transplantation suggest, however, that metabolic sink therapy may be efficacious. Gene therapy offers a more accessible approach for the treatment of methylmalonic aciduria than organ transplantation. Accordingly, we have evaluated a lentiviral vector-mediated gene transfer approach in an in vivo mouse model of methylmalonic aciduria. A mouse model of methylmalonic aciduria (Mut(-/-)MUT(h2)) was injected intravenously at 8 weeks of age with a lentiviral vector that expressed a codon-optimized human methylmalonyl coenzyme A mutase transgene, HIV-1SDmEF1αmurSigHutMCM. Untreated Mut(-/-)MUT(h2) and normal mice were used as controls. HIV-1SDmEF1αmurSigHutMCM-treated mice achieved near-normal weight for age, and Western blot analysis demonstrated significant methylmalonyl coenzyme A enzyme expression in their livers. Normalization of liver methylmalonyl coenzyme A enzyme activity in the treated group was associated with a reduction in plasma and urine methylmalonic acid levels, and a reduction in the hepatic methylmalonic acid concentration. Administration of the HIV-1SDmEF1αmurSigHutMCM vector provided significant, although incomplete, biochemical correction of methylmalonic aciduria in a mouse model, suggesting that gene therapy is a potential treatment for this disorder.
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Affiliation(s)
- Edward S Y Wong
- 1 Genetics and Molecular Pathology, Women's and Children's Hospital , North Adelaide, SA 5006, Australia
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7
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Hazra A, Kraft P, Lazarus R, Chen C, Chanock SJ, Jacques P, Selhub J, Hunter DJ. Genome-wide significant predictors of metabolites in the one-carbon metabolism pathway. Hum Mol Genet 2009; 18:4677-87. [PMID: 19744961 DOI: 10.1093/hmg/ddp428] [Citation(s) in RCA: 141] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Low plasma B-vitamin levels and elevated homocysteine have been associated with cancer, cardiovascular disease and neurodegenerative disorders. Common variants in FUT2 on chromosome 19q13 were associated with plasma vitamin B12 levels among women in a genome-wide association study in the Nurses' Health Study (NHS) NCI-Cancer Genetic Markers of Susceptibility (CGEMS) project. To identify additional loci associated with plasma vitamin B12, homocysteine, folate and vitamin B6 (active form pyridoxal 5'-phosphate, PLP), we conducted a meta-analysis of three GWA scans (total n = 4763, consisting of 1658 women in NHS-CGEMS, 1647 women in Framingham-SNP-Health Association Resource (SHARe) and 1458 men in SHARe). On chromosome 19q13, we confirm the association of plasma vitamin B12 with rs602662 and rs492602 (P-value = 1.83 x 10(-15) and 1.30 x 10(-14), respectively) in strong linkage disequilibrium (LD) with rs601338 (P = 6.92 x 10(-15)), the FUT2 W143X nonsense mutation. We identified additional genome-wide significant loci for plasma vitamin B12 on chromosomes 6p21 (P = 4.05 x 10(-08)), 10p12 (P-value=2.87 x 10(-9)) and 11q11 (P-value=2.25 x 10(-10)) in genes with biological relevance. We confirm the association of the well-studied functional candidate SNP 5,10-methylene tetrahydrofolate reductase (MTHFR) Ala222Val (dbSNP ID: rs1801133; P-value=1.27 x 10(-8)), on chromosome 1p36 with plasma homocysteine and identify an additional genome-wide significant locus on chromosome 9q22 (P-value=2.06 x 10(-8)) associated with plasma homocysteine. We also identified genome-wide associations with variants on chromosome 1p36 with plasma PLP (P-value=1.40 x 10(-15)). Genome-wide significant loci were not identified for plasma folate. These data reveal new biological candidates and confirm prior candidate genes for plasma homocysteine, plasma vitamin B12 and plasma PLP.
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Affiliation(s)
- Aditi Hazra
- Program in Molecular and Genetic Epidemiology, Department of Epidemiology, Harvard School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA.
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8
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Chiong MA, Sim KG, Carpenter K, Rhead W, Ho G, Olsen RKJ, Christodoulou J. Transient multiple acyl-CoA dehydrogenation deficiency in a newborn female caused by maternal riboflavin deficiency. Mol Genet Metab 2007; 92:109-14. [PMID: 17689999 DOI: 10.1016/j.ymgme.2007.06.017] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2007] [Revised: 06/11/2007] [Accepted: 06/11/2007] [Indexed: 12/18/2022]
Abstract
A newborn female presented on the first day of life with clinical and biochemical findings consistent with multiple acyl-CoA dehydrogenase deficiency (MADD). Riboflavin supplementation corrected the biochemical abnormalities 24 h after commencing the vitamin. In vitro acylcarnitine profiling in intact fibroblasts both in normal and riboflavin depleted media showed normal oxidation of fatty acids excluding defects in electron transfer flavoprotein (ETF), or ETF ubiquinone oxidoreductase (ETF:QO), or a genetic abnormality in flavin metabolism. In addition, sequencing of the genes encoding ETF and ETF:QO in the proband did not reveal any pathogenic mutations. Determination of the maternal riboflavin status after delivery showed that the mother was riboflavin deficient. Repeat testing done two years after the infant's birth and while on a normal diet showed that the mother was persistently riboflavin deficient and showed a typical MADD profile on plasma acylcarnitine testing. A possible genetic defect in riboflavin transport of metabolism in the mother is postulated to be the cause of the transient MADD seen in the infant. Sequencing of the SLC16A12, RFK and FLAD1 genes encoding key enzymes in riboflavin transport of metabolism in the mother did not identify any pathogenic mutations. The underlying molecular basis of the mother's defect in riboflavin metabolism remains to be established.
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Affiliation(s)
- M A Chiong
- Western Sydney Genetics Program, Children's Hospital at Westmead, and Discipline of Paediatrics and Child Health, University of Sydney, Sydney, Australia
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9
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Keeratichamroen S, Cairns JRK, Sawangareetrakul P, Liammongkolkul S, Champattanachai V, Srisomsap C, Kamolsilp M, Wasant P, Svasti J. Novel Mutations Found in Two Genes of Thai Patients with Isolated Methylmalonic Acidemia. Biochem Genet 2007; 45:421-30. [PMID: 17410422 DOI: 10.1007/s10528-007-9085-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2006] [Accepted: 01/09/2007] [Indexed: 12/01/2022]
Abstract
Molecular genetic analysis of three patients diagnosed with isolated methylmalonic acidemia (MMA) revealed that one was mut (0) MMA, with a mutation in the MUT gene encoding the L: -methylmalonyl-CoA mutase (MCM), and two were cblB MMA, with mutations in the MMAB gene required for synthesizing the deoxyadenosylcobalamin cofactor of MCM. The mut (0) patient was homozygous for a novel nonsense mutation in MUT, p.R31X (c.167C --> T), and heterozygous for three previously described polymorphisms, p.K212K (c.712A --> G), p.H532R (c.1671A --> G), and p.V671I (c.2087G --> A). The new MMAB mutation, p.E152X (c.454G --> T), was found to be homozygous in one cblB patient and heterozygous in the other patient, who also had four intron polymorphisms in this gene.
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Affiliation(s)
- Siriporn Keeratichamroen
- Laboratory of Biochemistry, Chulabhorn Research Institute, Vibhavadee Rangsit Road, Bangkok, 10210, Thailand
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10
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Worgan LC, Niles K, Tirone JC, Hofmann A, Verner A, Sammak A, Kucic T, Lepage P, Rosenblatt DS. Spectrum of mutations in mut methylmalonic acidemia and identification of a common Hispanic mutation and haplotype. Hum Mutat 2006; 27:31-43. [PMID: 16281286 DOI: 10.1002/humu.20258] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Cobalamin nonresponsive methylmalonic acidemia (MMA, mut complementation class) results from mutations in the nuclear gene MUT, which codes for the mitochondrial enzyme methylmalonyl CoA mutase (MCM). To better elucidate the spectrum of mutations that cause MMA, the MUT gene was sequenced in 160 patients with mut MMA. Sequence analysis identified mutations in 96% of disease alleles. Mutations were found in all coding exons, but predominantly in exons 2, 3, 6, and 11. A total of 116 different mutations, 68 of which were novel, were identified. Of the 116 different mutations, 53% were missense mutations, 22% were deletions, duplications or insertions, 16% were nonsense mutations, and 9% were splice-site mutations. Sixty-one of the mutations have only been identified in one family. A novel mutation in exon 2, c.322C>T (p.R108C), was identified in 16 of 27 Hispanic patients. SNP genotyping data demonstrated that Hispanic patients with this mutation share a common haplotype. Three other mutations were seen exclusively in Hispanic patients: c.280G>A (p.G94R), c.1022dupA, and c.970G>A (p.A324T). Seven mutations were seen almost exclusively in black patients, including the previously reported c.2150G>T (p.G717V) mutation, which was identified in 12 of 29 black patients. Two mutations were seen only in Asian patients. Some frequently identified mutations were not population-specific and were identified in patients of various ethnic backgrounds. Some of these mutations were found in mutation clusters in exons 2, 3, 6, and 11, suggesting a recurrent mutation.
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Affiliation(s)
- Lisa C Worgan
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
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Cavicchi C, Donati MA, Funghini S, la Marca G, Malvagia S, Ciani F, Poggi GM, Pasquini E, Zammarchi E, Morrone A. Genetic and biochemical approach to early prenatal diagnosis in a family with mut methylmalonic aciduria. Clin Genet 2006; 69:72-6. [PMID: 16451139 DOI: 10.1111/j.1399-0004.2005.00547.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Genetic and biochemical prenatal diagnosis was performed at 11 weeks of gestation in a family with a proband affected by mut methylmalonic aciduria (MMA) and homozygotes for the MUT gene c.643G>A (p.Gly215Ser) mutation. Both chorionic villus and amniotic fluid samples were used. The presence of high levels of methylmalonic acid and propionylcarnitine determined by gas chromatography/mass spectrometry and LC/MS/MS analysis, respectively, and the identification of the p.Gly215Ser at a homozygous level in foetal DNA allowed a certain, rapid and early diagnosis. To our knowledge, this is the first mut MMA prenatal diagnosis carried out by genetic and biochemical approach.
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Affiliation(s)
- C Cavicchi
- Metabolic and Muscular Unit, Department of Paediatrics, University of Florence, Meyer Children's Hospital, Florence, Italy
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12
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Chandler R, Venditti CP. Genetic and genomic systems to study methylmalonic acidemia. Mol Genet Metab 2005; 86:34-43. [PMID: 16182581 PMCID: PMC2657357 DOI: 10.1016/j.ymgme.2005.07.020] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2005] [Revised: 07/22/2005] [Accepted: 07/26/2005] [Indexed: 11/17/2022]
Abstract
Methylmalonic acidemia (MMAemia) is the biochemical hallmark of a group of genetic metabolic disorders that share a common defect in the ability to convert methylmalonyl-CoA into succinyl-CoA. This disorder is due to either a mutant methylmalonyl-CoA mutase apoenzyme or impaired synthesis of adenosylcobalamin, the cofactor for this enzyme. In this article, we will provide an overview of the pathways disrupted in these disorders, discuss the known metabolic blocks with a particular focus on molecular genetics, and review the use of selected model organisms to study features of methylmalonic acidemia.
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Affiliation(s)
| | - C. P. Venditti
- Corresponding author. Fax: +1 301 402 2170. Email address: (C. Venditti)
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13
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Martínez MA, Rincón A, Desviat LR, Merinero B, Ugarte M, Pérez B. Genetic analysis of three genes causing isolated methylmalonic acidemia: identification of 21 novel allelic variants. Mol Genet Metab 2005; 84:317-25. [PMID: 15781192 DOI: 10.1016/j.ymgme.2004.11.011] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2004] [Revised: 11/23/2004] [Accepted: 11/29/2004] [Indexed: 11/20/2022]
Abstract
Isolated methylmalonic aciduria (MMA) is an inborn error of metabolism due to the impaired isomerization of l-methylmalonyl-CoA to succinyl-CoA. This reaction is catalyzed by the mitochondrial protein methylmalonyl-CoA mutase (MCM, EC 5.4.99.2), an adenosylcobalamin-dependent enzyme. Four different forms of isolated MMA have been described: mut MMA associated with defects in the MCM apoenzyme, and phenotypically divided into two subtypes mut- and mut0 MMA, and three different defects involved in the synthesis of the active form of the cofactor adenosylcobalamin, termed cbl MMA, and classified into three different complementation groups cblA, cblB, and cblH associated with defects in the MMAA and MMAB genes and with an unidentified protein, respectively. In this work we describe the genetic analysis of 25 MMA patients, mainly from Spain. Using biochemical and cellular approaches our patients have been classified, identifying 13 mut MMA, 7 cblA, 2 cblB, and 3 noncblA, noncblB deficient patients. cDNA and genomic DNA sequence analysis of the MUT, MMAA, and MMAB genes have allowed us to identify 27 different changes, 21 novel ones. Among the missense mutations identified in the MUT gene only one, the c.970G>A (p.A324T) variant located in the substrate binding domain is likely a mut- mutation. The remaining missense mutations c.326A>G (p.Q109R), c.983T>C (p.L328P), c.1846C>T (p.R616C), and c.1850T>G (p.L617R) are probably mut0. In the MMAA patients analyzed, frameshift mutations are prevalent. We have explored the genotype-phenotype correlation for this clinically heterogeneous disease.
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14
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Parle-McDermott A, McManus EJ, Mills JL, O'Leary VB, Pangilinan F, Cox C, Weiler A, Molloy AM, Conley M, Watson D, Scott JM, Brody LC, Kirke PN. Polymorphisms within the vitamin B12 dependent methylmalonyl-coA mutase are not risk factors for neural tube defects. Mol Genet Metab 2003; 80:463-8. [PMID: 14654360 DOI: 10.1016/j.ymgme.2003.09.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Methionine synthase and methylmalonyl-CoA mutase (mutase) are the only two known vitamin B(12) (B(12)) dependent enzymes in humans. A lower level of B(12) has been shown to be an independent maternal risk factor for neural tube defects (NTDs) prompting an investigation of common genetic variants within B(12) dependent enzymes. To investigate the role of methylmalonyl-CoA mutase variants we studied 279 complete NTD triads (NTD affected case and both parents) and 256 controls. Based on case-control and family based (transmission disequilibrium test) analyses we did not find an association between the mutase single nucleotide polymorphisms (SNPs) K212K (636A-->G), H532R (1595A-->G) and V671I (2011G-->A) and NTDs. However, there was a significant difference in the frequencies of these polymorphisms between a group of African Americans and American Caucasians (K212K, P=0.002; H532R, P</=0.001; V671I, P=0.006). In conclusion, common variants in the mutase gene do not appear to be risk factors for NTDs but their allele frequencies are significantly different between ethnic groups.
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15
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Champattanachai V, Ketudat Cairns JR, Shotelersuk V, Keeratichamroen S, Sawangareetrakul P, Srisomsap C, Kaewpaluek V, Svasti J. Novel mutations in a Thai patient with methylmalonic acidemia. Mol Genet Metab 2003; 79:300-2. [PMID: 12948746 DOI: 10.1016/s1096-7192(03)00106-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A Thai patient with methylmalonic acidemia (MMA) and no methylmalonyl-CoA mutase (MCM, EC 5.4.99.2) activity in leukocytes in the presence of deoxyadenosyl cobalamin (mut(0)) was found to be heterozygous for two novel mutations: 1048delT and 1706_1707delGGinsTA (G544X), inherited from her mother and father, respectively. The proband was also heterozygous for the polymorphism, A499T, which did not affect the activity of recombinant MCM.
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Affiliation(s)
- Voraratt Champattanachai
- Laboratory of Biochemistry, Chulabhorn Research Institute, Vipavadee-Rangsit Highway, Bangkok 10210, Thailand
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16
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Ames BN, Elson-Schwab I, Silver EA. High-dose vitamin therapy stimulates variant enzymes with decreased coenzyme binding affinity (increased K(m)): relevance to genetic disease and polymorphisms. Am J Clin Nutr 2002; 75:616-58. [PMID: 11916749 DOI: 10.1093/ajcn/75.4.616] [Citation(s) in RCA: 218] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
As many as one-third of mutations in a gene result in the corresponding enzyme having an increased Michaelis constant, or K(m), (decreased binding affinity) for a coenzyme, resulting in a lower rate of reaction. About 50 human genetic dis-eases due to defective enzymes can be remedied or ameliorated by the administration of high doses of the vitamin component of the corresponding coenzyme, which at least partially restores enzymatic activity. Several single-nucleotide polymorphisms, in which the variant amino acid reduces coenzyme binding and thus enzymatic activity, are likely to be remediable by raising cellular concentrations of the cofactor through high-dose vitamin therapy. Some examples include the alanine-to-valine substitution at codon 222 (Ala222-->Val) [DNA: C-to-T substitution at nucleo-tide 677 (677C-->T)] in methylenetetrahydrofolate reductase (NADPH) and the cofactor FAD (in relation to cardiovascular disease, migraines, and rages), the Pro187-->Ser (DNA: 609C-->T) mutation in NAD(P):quinone oxidoreductase 1 [NAD(P)H dehy-drogenase (quinone)] and FAD (in relation to cancer), the Ala44-->Gly (DNA: 131C-->G) mutation in glucose-6-phosphate 1-dehydrogenase and NADP (in relation to favism and hemolytic anemia), and the Glu487-->Lys mutation (present in one-half of Asians) in aldehyde dehydrogenase (NAD + ) and NAD (in relation to alcohol intolerance, Alzheimer disease, and cancer).
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Affiliation(s)
- Bruce N Ames
- Department of Molecular and Cellular Biology, University of California, Berkeley, USA.
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17
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Berger I, Shaag A, Anikster Y, Baumgartner ER, Bar-Meir M, Joseph A, Elpeleg ON. Mutation analysis of the MCM gene in Israeli patients with mut(0) disease. Mol Genet Metab 2001; 73:107-10. [PMID: 11350191 DOI: 10.1006/mgme.2001.3166] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Three novel mutations (IVS8+3a --> g, N219Y, and E414X) were identified in 6 unrelated patients with mut(0) methylmalonic aciduria. The presence of a wild-type along with rearranged fragments in homozygotes for the IVS8+3a --> g mutation may contribute to their later age of onset (3-11 months of age). Nonetheless, delayed onset was not associated with better neurological outcome and prolonged survival. The large number of undiagnosed dead sibs in most families suggests that the disease is largely underdiagnosed in this region.
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Affiliation(s)
- I Berger
- The Metabolic Disease Unit, Shaare-Zedek Medical Center, Jerusalem 91030, Israel
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18
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Chun K, Robinson BH. Expression of normal and mutant pyruvate dehydrogenase complex E1 alpha cDNAs in cultured human lymphoblasts. Arch Biochem Biophys 1998; 349:246-50. [PMID: 9448711 DOI: 10.1006/abbi.1997.0476] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Transfection of PDH E1 alpha cDNAs into human normal (3781) and PDH-deficient (4787) lymphoblast cell lines was performed to study the expression of different E1 alpha cDNAs. Transfection of normal human E1 alpha cDNA into a severely PDH-deficient cell line with 10% residual activity resulted in a fivefold increase in residual PDH complex activity. Transfection of the normal cDNA into the normal cell line did not affect the residual enzyme activity. Transfection of three known human PDH E1 alpha mutations (A875T, C787G, and a 13-bp insertion at nucleotide 981) into the normal cell line resulted in a decrease of PDH complex activity. Expression of these same mutations in the deficient cell line resulted in an increase of PDH complex activity, with the C787G mutation causing the greatest increase in enzyme activity. The increase in activity seen with A875T expressed in the mutant cell line suggested that interallelic complementation had occurred.
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Affiliation(s)
- K Chun
- Department of Biochemistry, University of Toronto, Ontario, Canada
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19
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Abstract
Mut methylmalonic acidemia is caused by mutations in the MUT locus encoding the enzyme methylmalonyl CoA mutase. Genotypic and phenotypic variability in this disease has been studied extensively by biochemical and somatic cell genetic techniques, by molecular cloning, and by gene transfer. Mutations have been identified that cause classic mut(o) phenotypes in which there is no detectable enzymatic activity, mut- phenotypes in which there is residual cobalamin-dependent activity, as well as a subset within both mut(o) and mut- phenotypes that exhibit interallelic complementation. These mutations illustrate the position, structure, and function of critical domains within this cobalamin-binding enzyme and provide new insights into the biochemical and clinical consequences of enzyme deficiency.
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Affiliation(s)
- F D Ledley
- Department of Cell Biology, Baylor College of Medicine, Houston, Texas 77030, USA
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20
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Methylmalonyl-CoA mutase induction by cerebral ischemia and neurotoxicity of the mitochondrial toxin methylmalonic acid. J Neurosci 1996. [PMID: 8929440 DOI: 10.1523/jneurosci.16-22-07336.1996] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Differential screening of gerbil brain hippocampal cDNA libraries was used to search for genes expressed in ischemic, but not normal, brain. The methylmalonyl-CoA mutase (MCM) cDNA was highly expressed after ischemia and showed a 95% similarity to mouse and 91% similarity to the human MCM cDNAs. Transient global ischemia induced a fourfold increase in MCM mRNA on Northern blots from both hippocampus and whole forebrain. MCM protein exhibited a similar induction on Western blots of gerbil cerebral cortex 8 and 24 hr after ischemia. Treatment of primary brain astrocytes with either the branched-chain amino acid (BCAA) isoleucine or the BCAA metabolite, propionate, induced MCM mRNA fourfold. Increased concentrations of BCAAs and odd-chain fatty acids, both of which are metabolized to propionate, may contribute to inducing the MCM gene during ischemia. Methylmalonic acid, which is formed from the MCM substrate methylmalonyl-CoA and which inhibits succinate dehydrogenase (SDH), produced dose-related cell death when injected into the basal ganglia of adult rat brain. This neurotoxicity is similar to that of structurally related mitochondrial SDH inhibitors, malonate and 3-nitropropionic acid. Methylmalonic acid may contribute to neuronal injury in human conditions in which it accumulates, including MCM mutations and B12 deficiency. This study shows that methylmalonyl-CoA mutase is induced by several stresses, including ischemia, and would serve to decrease the accumulation of an endogenous cellular mitochondrial inhibitor and neurotoxin, methylmalonic acid.
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21
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Narasimhan P, Sklar R, Murrell M, Swanson RA, Sharp FR. Methylmalonyl-CoA mutase induction by cerebral ischemia and neurotoxicity of the mitochondrial toxin methylmalonic acid. J Neurosci 1996; 16:7336-46. [PMID: 8929440 PMCID: PMC6578931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Differential screening of gerbil brain hippocampal cDNA libraries was used to search for genes expressed in ischemic, but not normal, brain. The methylmalonyl-CoA mutase (MCM) cDNA was highly expressed after ischemia and showed a 95% similarity to mouse and 91% similarity to the human MCM cDNAs. Transient global ischemia induced a fourfold increase in MCM mRNA on Northern blots from both hippocampus and whole forebrain. MCM protein exhibited a similar induction on Western blots of gerbil cerebral cortex 8 and 24 hr after ischemia. Treatment of primary brain astrocytes with either the branched-chain amino acid (BCAA) isoleucine or the BCAA metabolite, propionate, induced MCM mRNA fourfold. Increased concentrations of BCAAs and odd-chain fatty acids, both of which are metabolized to propionate, may contribute to inducing the MCM gene during ischemia. Methylmalonic acid, which is formed from the MCM substrate methylmalonyl-CoA and which inhibits succinate dehydrogenase (SDH), produced dose-related cell death when injected into the basal ganglia of adult rat brain. This neurotoxicity is similar to that of structurally related mitochondrial SDH inhibitors, malonate and 3-nitropropionic acid. Methylmalonic acid may contribute to neuronal injury in human conditions in which it accumulates, including MCM mutations and B12 deficiency. This study shows that methylmalonyl-CoA mutase is induced by several stresses, including ischemia, and would serve to decrease the accumulation of an endogenous cellular mitochondrial inhibitor and neurotoxin, methylmalonic acid.
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Affiliation(s)
- P Narasimhan
- Department of Neurology, University of California, San Francisco 94143, USA
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22
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Thomä NH, Leadlay PF. Homology modeling of human methylmalonyl-CoA mutase: a structural basis for point mutations causing methylmalonic aciduria. Protein Sci 1996; 5:1922-7. [PMID: 8880917 PMCID: PMC2143539 DOI: 10.1002/pro.5560050919] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Point mutations in the human gene encoding coenzyme B12 (adenosylcobalamin)-dependent methylmalonyl-CoA mutase give rise to an inherited disorder of propionic acid metabolism termed mut methylmalonic aciduria. Almost all such mutations alter amino acids in the homodimeric human enzyme that are identical to residues in the catalytic alpha-subunit of the heterodimeric methylmalonyl-CoA mutase from the bacterium Propionibacterium shermanii, to which the mature human enzyme shows an overall 65% sequence identity. To explore how specific mutations might cause the observed clinical phenotype, 12 known mutations were mapped onto a three-dimensional homology model of the subunit of the human enzyme, generated using the program MODELLER on the basis of the recently published 2.0 A X-ray crystal structure of the P. shermanii methylmalonyl-CoA mutase. Eight mutations are found in the C-terminal B12-binding domain, of which 4 (G623R, G626C, G630E, G703R) are in direct contact with the corrin and are clustered around the histidine ligand (H627) provided by the protein to coordinate the cobalt atom of the B12 cofactor. Introduction of a side chain, particularly one that is charged, at any of these positions is expected to disrupt the flavodoxin-like fold and severely impair its binding of B12. Mutation at either of two other highly conserved glycine residues in this domain (G648D, G717V) also disrupts critical elements in the fold as would the introduction of an additional positive charge in the mutation H678R. Mutation of an arginine in a solvent-exposed loop to a hydrophobic residue (R694W) is also pathogenic. The remaining mutations have been mapped to the N-terminal region of the mutase, two of which introduce a buried, uncompensated charge, either near the subunit interface (A377E), or near the narrow channel through which acyl-CoA esters gain access to the active site (W105R). The extreme N-terminus of methylmalonyl-CoA mutase is predicted to make extensive contacts with the other subunit, and a mutant in this region (R93H) may prevent the correct assembly of the dimer.
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Affiliation(s)
- N H Thomä
- Cambridge Centre for Molecular Recognition, University of Cambridge, United Kingdom
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23
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Drennan CL, Matthews RG, Rosenblatt DS, Ledley FD, Fenton WA, Ludwig ML. Molecular basis for dysfunction of some mutant forms of methylmalonyl-CoA mutase: deductions from the structure of methionine synthase. Proc Natl Acad Sci U S A 1996; 93:5550-5. [PMID: 8643613 PMCID: PMC39284 DOI: 10.1073/pnas.93.11.5550] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Inherited defects in the gene for methylmalonyl-CoA mutase (EC 5.4.99.2) result in the mut forms of methylmalonic aciduria. mut- mutations lead to the absence of detectable mutase activity and are not corrected by excess cobalamin, whereas mut- mutations exhibit residual activity when exposed to excess cobalamin. Many of the mutations that cause methylmalonic aciduria in humans affect residues in the C-terminal region of the methylmalonyl-CoA mutase. This portion of the methylmalonyl-CoA mutase sequence can be aligned with regions in other B12 (cobalamin)-dependent enzymes, including the C-terminal portion of the cobalamin-binding region of methionine synthase. The alignments allow the mutations of human methylmalonyl-CoA mutase to be mapped onto the structure of the cobalamin-binding fragment of methionine synthase from Escherichia coli (EC 2.1.1.13), which has recently been determined by x-ray crystallography. In this structure, the dimethylbenzimidazole ligand to the cobalt in free cobalamin has been displaced by a histidine ligand, and the dimethylbenzimidazole nucleotide "tail" is thrust into a deep hydrophobic pocket in the protein. Previously identified mut0 and mut- mutations (Gly-623 --> Arg, Gly-626 --> Cys, and Gly-648 --> Asp) of the mutase are predicted to interfere with the structure and/or stability of the loop that carries His-627, the presumed lower axial ligand to the cobalt of adenosylcobalamin. Two mutants that lead to severe impairment (mut0) are Gly-630 --> Glu and Gly-703 --> Arg, which map to the binding site for the dimethylbenzimidazole nucleotide substituent of adenosylcobalamin. The substitution of larger residues for glycine is predicted to block the binding of adenosylcobalamin.
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Affiliation(s)
- C L Drennan
- Biophysics Research Division and Department of Biological Chemistry, The University of Michigan, Ann Arbor 48109, USA
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24
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Smith LM, Meijer WG, Dijkhuizen L, Goodwin PM. A protein having similarity with methylmalonyl-CoA mutase is required for the assimilation of methanol and ethanol by Methylobacterium extorquens AM1. MICROBIOLOGY (READING, ENGLAND) 1996; 142 ( Pt 3):675-684. [PMID: 8868443 DOI: 10.1099/13500872-142-3-675] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A 4.0 kb region of Methylobacterium extorquens AM1 DNA which complements three mutants unable to convert acetyl-CoA to glyoxylate (and therefore defective in the assimilation of methanol and ethanol) has been isolated and sequenced. It contains two ORFs and the 3'-end of a third one. The mutations in all three mutants mapped within the first ORF, which was designated meaA; it encodes a protein having similarity with methylmalonyl-CoA mutase. However, methylmalonyl-CoA mutase was measured in extracts of one of the mutants and the specific activity was found to be similar to that in extracts of wild-type cells. Furthermore, although the predicted meaA gene product has the proposed cobalamin-binding site, it does not contain a highly conserved sequence (RIARNT) which is present in all known methylmalonyl-CoA mutases; meaA may therefore encode a novel vitamin-B12-dependent enzyme. The predicted polypeptide encoded by the second ORF did not have similarity with any known proteins. The partial ORF encoded a protein with similarity with the 3-oxoacyl-[acyl-carrier-protein] reductases; it was not essential for growth on methanol or ethanol.
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Affiliation(s)
- Loraine M Smith
- Department of Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Kerklaan 30, 9751 NN Haren, The Netherlands
- School of Cell and Molecular Biology, NESCOT, Reigate Road, Epsom KT17 3DS, UK
| | - Wim G Meijer
- Department of Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Kerklaan 30, 9751 NN Haren, The Netherlands
| | - Lubbert Dijkhuizen
- Department of Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Kerklaan 30, 9751 NN Haren, The Netherlands
| | - Pat M Goodwin
- School of Cell and Molecular Biology, NESCOT, Reigate Road, Epsom KT17 3DS, UK
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25
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Jackson CA, Kirszbaum L, Dashper S, Reynolds EC. Cloning, expression and sequence analysis of the genes encoding the heterodimeric methylmalonyl-CoA mutase of Porphyromonas gingivalis W50. Gene 1995; 167:127-32. [PMID: 8566763 DOI: 10.1016/0378-1119(95)00682-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Two genes that encode methylmalonyl-CoA mutase (MCM) have been characterised in Porphyromonas gingivalis W50 (Pg). The genes, designated mcmA and mcmB are transcribed in an operon and encode the MCM small subunit (SS, 68,626 Da) and the MCM large subunit (LS, 78,703 Da), respectively. A recombinant Escherichia coli (Ec) clone harbouring the Pg mcmA and mcmB genes expressed MCM activity 280-times higher than that of the Ec control. The C terminus of the MCM LS has sequence homology to domains of a variety of enzymes that consume or produce methylmalonyl-CoA, suggesting that the MCM LS C-terminal domain is involved in substrate binding. The MCM LS C-terminal region also exhibits homology to other enzymes that have cobalamin-containing cofactors. It is likely, therefore, that the C terminus of the MCM LS is an important MCM domain involved in both substrate and cofactor binding.
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Affiliation(s)
- C A Jackson
- Biochemistry and Molecular Biology Unit, School of Dental Science, University of Melbourne, Australia
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26
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Touraine RL, Rolland MO, Divry P, Mathieu M, Guibaud P, Bozon D. A 13-bp deletion (1952 del 13) in the methylmalonyl CoA mutase gene of an affected patient. Hum Mutat 1995; 5:354-6. [PMID: 7627195 DOI: 10.1002/humu.1380050417] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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27
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Wakazono A, Fukao T, Yamaguchi S, Hori T, Orii T, Lambert M, Mitchell GA, Lee GW, Hashimoto T. Molecular, biochemical, and clinical characterization of mitochondrial acetoacetyl-coenzyme A thiolase deficiency in two further patients. Hum Mutat 1995; 5:34-42. [PMID: 7728148 DOI: 10.1002/humu.1380050105] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The molecular basis of mitochondrial acetoacetyl-CoA thiolase (T2) deficiency was studied in two patients (GK11 and GK16). Fibroblasts from each patient had detectable immunoreactive T2 polypeptide (CRM). In pulse-chase experiments, fibroblasts from GK11 had two types of CRM: one (type I CRM) disappeared after a 24-hr chase and migrated more slowly than that of the normal control; the other (type II CRM) was detected with a small amount even after a 72-hr chase and had normal electrophoretic mobility. GK16's fibroblasts had a CRM (type III) which was also detectable even after a 72-hr chase and showed a slower mobility than type I CRM. By analyzing amplified cDNA and genomic fragments, we showed that both patients are genetic compounds; GK11 for the mutations N158D and T297M, and GK16 for the mutations A301P and IVS8 (+1). Expression analyses confirmed that mutant T2 subunits with N158D, T297M, and A301P correspond to type I, II, and III CRM, respectively. Among them, only the mutant T2 polypeptide with T297M appeared to have a detectable residual activity, in spite of its instability. Cotransfection of two cDNAs containing N158D and T297M suggested that heterotetramer formation reduces residual activity in GK11 cells.
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Affiliation(s)
- A Wakazono
- Department of Pediatrics, Gifu University School of Medicine, Japan
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28
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Qureshi AA, Rosenblatt DS, Cooper BA. Inherited disorders of cobalamin metabolism. Crit Rev Oncol Hematol 1994; 17:133-51. [PMID: 7818787 DOI: 10.1016/1040-8428(94)90022-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Affiliation(s)
- A A Qureshi
- Department of Human Genetics, McGill University, Royal Victoria Hospital, Montreal, Quebec, Canada
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29
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Crane AM, Ledley FD. Clustering of mutations in methylmalonyl CoA mutase associated with mut- methylmalonic acidemia. Am J Hum Genet 1994; 55:42-50. [PMID: 7912889 PMCID: PMC1918235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Mutations have been described in human methylmalonyl CoA mutase (MCM) that exhibit partial defects in enzyme activity, including cobalamin-dependent (i.e., mut-) or interallelic complementation. This work describes mutations in cells from four patients, three of whom exhibit a cobalamin-dependent phenotype and all four of whom exhibit interallelic complementation. Four novel mutations (R694W, G648D, G630E, and G626C) are identified that cluster near the carboxyl terminus of the protein, a region close to another mut- mutation (G717V). Each of these mutations was shown to express a phenotype congruent with that of the parental cell line, after transfection into mut0 fibroblasts, and each exhibits interallelic complementation in cotransfection assays with clones bearing a R93H mutation. The activity of mutant enzymes expressed in Saccharomyces cerevisiae parallels the residual activity of the parental cell lines and exhibits novel sensitivities to pH and salt. The clustering of these mutations identifies a region of MCM that most likely represents the cobalamin-binding domain. The location of this domain, as well as the pattern of sequence preservation between the homologous human and Probiono-bacterium shermanii enzymes, suggests a mechanism for interallelic complementation in which the cobalamin-binding defect is complemented in trans from the heterologous subunits of the dimer.
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Affiliation(s)
- A M Crane
- Department of Cell Biology, Baylor College of Medicine, Houston, TX 77030
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30
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Gravel RA, Akerman BR, Lamhonwah AM, Loyer M, Léon-del-Rio A, Italiano I. Mutations participating in interallelic complementation in propionic acidemia. Am J Hum Genet 1994; 55:51-8. [PMID: 8023851 PMCID: PMC1918217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Deficiency of propionyl-CoA carboxylase (PCC; alpha 4 beta 4) results in the rare, autosomal recessive disease propionic acidemia. Cell fusion experiments have revealed two complementation groups, pccA and pccB, corresponding to defects of the PCCA (alpha-subunit) and PCCB (beta-subunit) genes, respectively. The pccBCC group includes subgroups, pccB and pccC, which are thought to reflect interallelic complementation between certain mutations of the PCCB gene. In this study, we have identified the mutations in two pccB, one pccC, and two pccBC cell lines and have deduced those alleles participating in interallelic complementation. One pccB line was a compound heterozygote of Pro228Leu and Asn536Asp. The latter mutation was also detected in a noncomplementing pccBC line. This leaves Pro228Leu responsible for complementation in the pccB cells. The second pccB line contained an insertional duplication, dupKICK140-143, and a splice mutation IVS + 1 G-->T, located after Lys466. We suggest that the dupKICK mutation is the complementing allele, since the second allele is incompatible with normal splicing. The pccC line studied was homozygous for Arg410Trp, which is necessarily the complementing allele in that line. For a second pccC line, we previously had proposed that delta Ile408 was the complementing allele. We now show that its second allele, "Ins.Del," a 14-bp deletion replaced by a 12-bp insertion beginning at codon 407, fails to complement in homozygous form. We conclude that the interallelic complementation results from mutations in domains that can interact between beta-subunits in the PCC heteromer to restore enzymatic function. On the basis of sequence homology with the Propionibacterium shermanii transcarboxylase 12S subunit, we suggest that the pccC domain, defined by Ile408 and Arg410, may involve the propionyl-CoA binding site.
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Affiliation(s)
- R A Gravel
- McGill University-Montreal Children's Hospital Research Institute, Quebec, Canada
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Qureshi AA, Crane AM, Matiaszuk NV, Rezvani I, Ledley FD, Rosenblatt DS. Cloning and expression of mutations demonstrating intragenic complementation in mut0 methylmalonic aciduria. J Clin Invest 1994; 93:1812-9. [PMID: 7909321 PMCID: PMC294249 DOI: 10.1172/jci117166] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The mut0 mutation resulting in methylmalonyl CoA mutase (MCM) apoenzyme deficiency and methylmalonic aciduria is characterized by undetectable enzyme activity in cell extracts and low incorporation of propionate into cultured cells which is not stimulated by hydroxycobalamin. A mut0 fibroblast cell line (WG1681) from an African-American male infant complemented another mut0 cell line (WG 1130). Cloning and sequencing of cDNA from WG 1681 demonstrated compound heterozygosity for two novel changes at highly conserved sites: G623R and G703R. In addition, two previously described homozygous polymorphisms, H532R and V671I, were found. Hybridization of allele-specific oligonucleotides to PCR amplified MCM exons from the proband and family members identified a clinically normal mother, half-sister, and half-brother as carriers of the G703R change in cis with both polymorphisms. Transfection of each change into a mut0 cell line with very low MCM mRNA (GM1673) demonstrated a lack of stimulation of propionate uptake in the absence and presence of hydroxycobalamin. Cotransfection of each mutation with the previously identified R93H mutation of WG 1130 stimulated propionate uptake, indicating that G623R and G703R are independently capable of complementing the R93H mutation.
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Affiliation(s)
- A A Qureshi
- Department of Human Genetics, McGill University Montreal, Quebec, Canada
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Wilkemeyer M, Stankovics J, Foy T, Ledley FD. Propionate metabolism in cultured human cells after overexpression of recombinant methylmalonyl CoA mutase: implications for somatic gene therapy. ACTA ACUST UNITED AC 1993; 18:493-505. [PMID: 1363155 DOI: 10.1007/bf01232646] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Strategies for somatic gene therapy must consider the metabolic consequences of expressing the recombinant gene product in addition to methods for gene transfer and expression. We describe studies of propionate metabolism in cultured cells transfected with methylmalonyl CoA mutase (MCM), the enzyme deficient in mut methylmalonic acidemia. Transfection of MCM into mut fibroblasts restores propionate metabolism to normal levels in a dose-dependent manner. Overexpression of MCM, or the addition of excess propionate, carnitine, or cobalamin, does not increase propionate metabolism in normal human fibroblasts, lymphoblasts, or hepatoma cells, although hepatic cells exhibit > 10-fold higher levels of propionate metabolism. Significantly, the restoration of propionate metabolism in mut fibroblasts is disproportionately greater than the efficiency of transfection, suggesting the presence of a cooperative phenomenon between cells. Intercellular participation in propionate metabolism is evident in cocultures of MCM-deficient and propionyl CoA carboxylase-deficient cells. We conclude that the liver is the preferred target for gene therapy of MCM deficiency because of its greater capacity for propionate metabolism and that cooperation between cells could enhance the biological effect of a subpopulation of cells transformed with recombinant MCM.
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Affiliation(s)
- M Wilkemeyer
- Department of Cell Biology and Pediatrics, Baylor College of Medicine, Houston, Texas 77030
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Shevell MI, Matiaszuk N, Ledley FD, Rosenblatt DS. Varying neurological phenotypes among muto and mut- patients with methylmalonylCoA mutase deficiency. AMERICAN JOURNAL OF MEDICAL GENETICS 1993; 45:619-24. [PMID: 7681251 DOI: 10.1002/ajmg.1320450521] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
MethylmalonylCoA mutase (MCM) is a mitochondrial homodimer responsible for the isomerization of methylmalonylCoA to succinylCoA. Apomutase defects are traditionally divided into muto and mut- classes on the basis of residual mutase activity. Clinical findings were reviewed in 20 patients with methylmalonic aciduria secondary to MCM deficiency. All 11 muto patients had an early neonatal presentation; 6 of these patients died in infancy and 3 of 5 survivors had a poor neurological outcome as evidenced by severe delay or spastic quadriparesis with dystonia. The 2 other survivors include a 27-month-old child with a mild delay in verbal and fine motor skills and an adolescent with low normal intelligence. Of the 9 mut- patients, 7 became symptomatic in late infancy or childhood and 2 were picked up on screening. Two of the 9 patients have never had an episode of metabolic decompensation yet both are neurologically compromised; one severely retarded and autistic, the other mildly delayed. Four mut- patients have had episodic acidosis and are neurologically moderately affected, while 3 have had episodic acidosis and are neurologically intact. These results confirm phenotypic pleomorphism without a consistent pattern of neurological injury and suggest some broad correlation between mutase class and phenotype. Survival with good outcome is possible among muto patients as is significant morbidity among mut- patients. Acidosis and metabolic imbalance are not necessary preconditions for significant morbidity.
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Affiliation(s)
- M I Shevell
- Division of Pediatric Neurology, Montreal Children's Hospital, Quebec, Canada
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Sawada T, Ledley FD. Correction of methylmalonyl-CoA mutase deficiency inMut o fibroblasts and constitution of gene expression in primary human hepatocytes by retroviral-mediated gene transfer. ACTA ACUST UNITED AC 1992; 18:507-16. [PMID: 1363156 DOI: 10.1007/bf01232647] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Methylmalonic acidemia is an often fatal inborn error of organic acid metabolism due to deficiency of methylmalonyl-CoA mutase. The cloning of genes encoding this enzyme and the advent of technologies for gene transfer have introduced the possibility of somatic gene therapy for this disorder. Gene therapy may require replacement of the defective enzyme in hepatocytes, which have a greater capacity for propionate metabolism than other somatic cells and represent the principle physiological site of propionate metabolism. We describe construction of an amphotropic retroviral vector containing the human methylmalonyl-CoA mutase cDNA. This vector is shown to transduce primary MCM-deficient fibroblasts and restore levels of [14C]propionate metabolism by cultures of nonselected cells to normal. This vector will transduce primary human hepatocytes and direct transcription of recombinant human MCM from the integrated provirus. This work demonstrates the feasibility of retroviral-mediated gene transfer of methylmalonyl-CoA mutase into primary human cells, including hepatocytes which represent a difficult, but potentially necessary, target for gene therapy of methylmalonic acidemia.
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Affiliation(s)
- T Sawada
- Howard Hughes Medical Institute, Department of Cell Biology, Baylor College of Medicine, Houston, Texas 77030
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Crane AM, Martin LS, Valle D, Ledley FD. Phenotype of disease in three patients with identical mutations in methylmalonyl CoA mutase. Hum Genet 1992; 89:259-64. [PMID: 1351030 DOI: 10.1007/bf00220536] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have previously identified a mutation in the gene for methylmalonyl CoA mutase in a patient with the mut- phenotype of methylmalonic aciduria. This mutation (G717V) interferes with the binding of the deoxyadenosylcobalamin cofactor to the apoenzyme producing a mutant holoenzyme that is defective, but not completely inactive, in vitro. This report describes the clinical phenotype associated with this mutation in the original patient and two additional patients who are homozygous for this allele. All three patients presented in the first years of life with multiple episodes of life-threatening organic acidosis and hyperammonemia. None had evidence of disease in the perinatal period, and all three have low-normal intelligence. These three children exhibit a distinctive phenotype of disease that is intermediate between the fulminant and benign forms of methylmalonic aciduria. These data suggest that this phenotype is the specific consequence of the G717V mutation, and that the degree of residual enzyme activity associated with the G717V mutation is close to the threshold required in vivo for maintaining metabolic homeostasis.
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Affiliation(s)
- A M Crane
- Department of Cell Biology, Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030
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