Encephalomyopathy with methylmalonic aciduria

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Prevalence of clinical parameters (%)

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Pubmed id number as a reference Organ system affected
Number of patients in the reference Percent affected patients (Between 0 and 1, eg. 0.1 = 10%)
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List of symptoms

Symptom/sign Organ system Percent affected Pubmed id Added on(yyyy-mm-dd) Edit/add reference
Hearing loss nervous 100 % 17301081 2011-10-19
Mental retardation nervous 100 % 15877282 2011-10-11
Hypotonia nervous 100 % 17301081 2011-10-11
Developmental delay nervous 100 % 15877282 2011-10-11
Hypotonia nervous 100 % 15877282 2011-10-11
Hearing loss nervous 100 % 15877282 2011-10-18
Seizures nervous 100 % 15877282 2011-10-11
Developmental delay multi 100 % 17301081 2011-10-12
Dystonia nervous 93 % 17301081 2011-10-11
Cerebral atrophy nervous 91 % 17301081 2011-10-14
Basal ganglia pathology nervous 90 % 17301081 2011-10-14
Lactate accumulation circulatory 83 % 17301081 2011-10-11
Neuropathy nervous 71 % 17301081 2011-10-12
Ophthalmoplegia nervous 71 % 17301081 2011-10-11
Gastrointestinal dysmotility digestive 50 % 15877282 2011-10-11
Cerebral atrophy nervous 50 % 15877282 2011-10-11
Contracture nervous 50 % 15877282 2011-10-11
Dystonia nervous 50 % 15877282 2011-10-11
Ptosis nervous 50 % 15877282 2011-10-11
Cerebellar atrophy nervous 18 % 17301081 2011-10-14

List of references:

SUCLA2 mutations are associated with mild methylmalonic aciduria, Leigh-like encephalomyopathy, dystonia and deafness.
Rosalba Carrozzo, Carlo Dionisi-Vici, Ulrike Steuerwald, Simona Lucioli, Federica Deodato, Sivia Di Giandomenico, Enrico Bertini, Barbara Franke, Leo A J Kluijtmans, Maria Chiara Meschini, Cristiano Rizzo, Fiorella Piemonte, Richard Rodenburg, René Santer, Filippo M Santorelli, Arno van Rooij, Diana Vermunt-de Koning, Eva Morava, Ron A Wevers,

One pedigree with four patients has been recently described with mitochondrial DNA depletion and mutation in SUCLA2 gene leading to succinyl-CoA synthase deficiency. Patients had a Leigh-like encephalomyopathy and deafness but besides the presence of lactic acidosis, the profile of urine organic acid was not reported. We have studied 14 patients with mild 'unlabelled' methylmalonic aciduria (MMA) from 11 families. Eight of the families are from the Faroe Islands, having a common ancestor, and three are from southern Italy. Since the reaction catalysed by succinyl-CoA synthase in the tricarboxylic acid (TCA) cycle represents a distal step of the methylmalonic acid pathway, we investigated the SUCLA2 gene as a candidate gene in our patients. Genetic analysis of the gene in the 14 patients confirmed the defect in all patients and led to the identification of three novel mutations (p.Gly118Arg; p.Arg284Cys; c.534 + 1G --> A). The defect could be convincingly shown at the protein level and our data also confirm the previously described mitochondrial DNA depletion. Defects in SUCLA2 can be found at the metabolite level and are defined by mildly elevated methylmalonic acid and C4-dicarboxylic carnitine concentrations in body fluids in association with variable lactic acidosis. Clinically the diagnosis should be considered in patients with early/neonatal onset encephalomyopathy, dystonia, deafness and Leigh-like MRI abnormalities mainly affecting the putamen and the caudate nuclei. The frequency of the mutated allele in the Faroese population amounted to 2%, corresponding with an estimated homozygote frequency of 1 : 2500. Our data extend knowledge on the genetic defects causing MMA. Our patients present with an early infantile Leigh-like encephalomyopathy with deafness, and later on a progressive dystonia. Mild MMA, lactic acidosis and specific abnormalities in the carnitine ester profile are the biochemical hallmarks of the disease. In view of the frequency of the mutated allele on the Faroe Islands, measures become feasible to prevent the occurrence of the disease on the islands. We confirm and extend the findings on this inborn error of metabolism in the TCA cycle that must be carefully investigated by accurate metabolite analyses.

Brain : a journal of neurology - Mar 2007

Deficiency of the ADP-forming succinyl-CoA synthase activity is associated with encephalomyopathy and mitochondrial DNA depletion.
Orly Elpeleg, Chaya Miller, Eli Hershkovitz, Maria Bitner-Glindzicz, Gili Bondi-Rubinstein, Shamima Rahman, Alistair Pagnamenta, Sharon Eshhar, Ann Saada,

The mitochondrial DNA (mtDNA) depletion syndrome is a quantitative defect of mtDNA resulting from dysfunction of one of several nuclear-encoded factors responsible for maintenance of mitochondrial deoxyribonucleoside triphosphate (dNTP) pools or replication of mtDNA. Markedly decreased succinyl-CoA synthetase activity due to a deleterious mutation in SUCLA2, the gene encoding the beta subunit of the ADP-forming succinyl-CoA synthetase ligase, was found in muscle mitochondria of patients with encephalomyopathy and mtDNA depletion. Succinyl-CoA synthetase is invariably in a complex with mitochondrial nucleotide diphosphate kinase; hence, we propose that a defect in the last step of mitochondrial dNTP salvage is a novel cause of the mtDNA depletion syndrome.

American journal of human genetics - Jun 2005