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Orphanet Journal of Rare Diseases Sep 2014Methylmalonic and propionic acidemia (MMA/PA) are inborn errors of metabolism characterized by accumulation of propionic acid and/or methylmalonic acid due to deficiency... (Review)
Review
Methylmalonic and propionic acidemia (MMA/PA) are inborn errors of metabolism characterized by accumulation of propionic acid and/or methylmalonic acid due to deficiency of methylmalonyl-CoA mutase (MUT) or propionyl-CoA carboxylase (PCC). MMA has an estimated incidence of ~ 1: 50,000 and PA of ~ 1:100'000 -150,000. Patients present either shortly after birth with acute deterioration, metabolic acidosis and hyperammonemia or later at any age with a more heterogeneous clinical picture, leading to early death or to severe neurological handicap in many survivors. Mental outcome tends to be worse in PA and late complications include chronic kidney disease almost exclusively in MMA and cardiomyopathy mainly in PA. Except for vitamin B12 responsive forms of MMA the outcome remains poor despite the existence of apparently effective therapy with a low protein diet and carnitine. This may be related to under recognition and delayed diagnosis due to nonspecific clinical presentation and insufficient awareness of health care professionals because of disease rarity.
Topics: Amino Acid Metabolism, Inborn Errors; Humans; Practice Guidelines as Topic; Propionic Acidemia
PubMed: 25205257
DOI: 10.1186/s13023-014-0130-8 -
Intractable & Rare Diseases Research May 2018Methylmalonic acidemia (MMA) is a lethal, severe heterogeneous disorder of methylmalonate and cobalamin (cbl; vitamin B12) metabolism with poor prognosis. Two main forms... (Review)
Review
Methylmalonic acidemia (MMA) is a lethal, severe heterogeneous disorder of methylmalonate and cobalamin (cbl; vitamin B12) metabolism with poor prognosis. Two main forms of the disease have been identified, isolated methylmalonic acidurias and combined methylmalonic aciduria and homocystinuria, which is respectively caused by different gene mutations. Here, we review the improvement of pathogenesis, diagnosis and treatment in MMA. Importantly, the reported epidemiological data of MMA patients in China and the hot mutation sites in Chinese patients are listed, which will aid in improving healthcare of Chinese patients in the future. c.729_730insTT was the most common mutation in Chinese isolated MMA patients, while c.609G>A and c.658_660delAAG were in Chinese cblC type patients according to unrelated studies. The estimated newborn screening incidence was reported to be 1:26,000, 1:3,920, 1:11,160, 1:6,032 respectively in Beijing and Shanghai, Shandong province, Taian district, and Henan province of China. Alternatively, when patients with suspected inherited metabolic diseases were used as the screened sample, the relatively high incidence 0.3% and 1.32% were respectively obtained in southern China and throughout all the provinces of mainland China and Macao with the exception of five provinces (Hainan, Neimenggu, Tibet, Ningxia, and Hong Kong).
PubMed: 29862147
DOI: 10.5582/irdr.2018.01026 -
Journal of Inherited Metabolic Disease May 2021Isolated methylmalonic acidaemia (MMA) and propionic acidaemia (PA) are rare inherited metabolic diseases. Six years ago, a detailed evaluation of the available...
Isolated methylmalonic acidaemia (MMA) and propionic acidaemia (PA) are rare inherited metabolic diseases. Six years ago, a detailed evaluation of the available evidence on diagnosis and management of these disorders has been published for the first time. The article received considerable attention, illustrating the importance of an expert panel to evaluate and compile recommendations to guide rare disease patient care. Since that time, a growing body of evidence on transplant outcomes in MMA and PA patients and use of precursor free amino acid mixtures allows for updates of the guidelines. In this article, we aim to incorporate this newly published knowledge and provide a revised version of the guidelines. The analysis was performed by a panel of multidisciplinary health care experts, who followed an updated guideline development methodology (GRADE). Hence, the full body of evidence up until autumn 2019 was re-evaluated, analysed and graded. As a result, 21 updated recommendations were compiled in a more concise paper with a focus on the existing evidence to enable well-informed decisions in the context of MMA and PA patient care.
Topics: Amino Acid Metabolism, Inborn Errors; Disease Management; Humans; Propionic Acidemia
PubMed: 33595124
DOI: 10.1002/jimd.12370 -
Journal of Inherited Metabolic Disease May 2023Methylmalonic acidemia (MMA) is a severe inborn error of metabolism that is characterized by pleiotropic metabolic perturbations and multiorgan pathology. Treatment... (Review)
Review
Methylmalonic acidemia (MMA) is a severe inborn error of metabolism that is characterized by pleiotropic metabolic perturbations and multiorgan pathology. Treatment options are limited and non-curative as the underlying causative molecular mechanisms remain unknown. While earlier studies have focused on the potential direct toxicity of metabolites such as methylmalonic and propionic acid as a mechanism to explain disease pathophysiology, new observations have revealed that aberrant acylation, specifically methylmalonylation, is a characteristic feature of MMA. The mitochondrial sirtuin enzyme SIRT5 is capable of recognizing and removing this PTM, however, reduced protein levels of SIRT5 along with other mitochondrial SIRTs 3 and 4 in MMA and potentially reduced function of all three indicates aberrant acylation may require clinical intervention. Therefore, targeting posttranslational modifications may represent a new therapeutic approach to treat MMA and related organic acidemias.
Topics: Humans; Amino Acid Metabolism, Inborn Errors; Mitochondria; Methylmalonyl-CoA Mutase; Methylmalonic Acid; Propionic Acidemia
PubMed: 37078237
DOI: 10.1002/jimd.12617 -
Journal of Inherited Metabolic Disease Jul 2019Vitamin B (cobalamin, Cbl) is a nutrient essential to human health. Due to its complex structure and dual cofactor forms, Cbl undergoes a complicated series of... (Review)
Review
Vitamin B (cobalamin, Cbl) is a nutrient essential to human health. Due to its complex structure and dual cofactor forms, Cbl undergoes a complicated series of absorptive and processing steps before serving as cofactor for the enzymes methylmalonyl-CoA mutase and methionine synthase. Methylmalonyl-CoA mutase is required for the catabolism of certain (branched-chain) amino acids into an anaplerotic substrate in the mitochondrion, and dysfunction of the enzyme itself or in production of its cofactor adenosyl-Cbl result in an inability to successfully undergo protein catabolism with concomitant mitochondrial energy disruption. Methionine synthase catalyzes the methyl-Cbl dependent (re)methylation of homocysteine to methionine within the methionine cycle; a reaction required to produce this essential amino acid and generate S-adenosylmethionine, the most important cellular methyl-donor. Disruption of methionine synthase has wide-ranging implications for all methylation-dependent reactions, including epigenetic modification, but also for the intracellular folate pathway, since methionine synthase uses 5-methyltetrahydrofolate as a one-carbon donor. Folate-bound one-carbon units are also required for deoxythymidine monophosphate and de novo purine synthesis; therefore, the flow of single carbon units to each of these pathways must be regulated based on cellular needs. This review provides an overview on Cbl metabolism with a brief description of absorption and intracellular metabolic pathways. It also provides a description of folate-mediated one-carbon metabolism and its intersection with Cbl at the methionine cycle. Finally, a summary of recent advances in understanding of how both pathways are regulated is presented.
Topics: 5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase; Animals; Folic Acid; Folic Acid Deficiency; Humans; Methylmalonyl-CoA Mutase; Vitamin B 12; Vitamin B 12 Deficiency
PubMed: 30693532
DOI: 10.1002/jimd.12009 -
Taiwanese Journal of Obstetrics &... Mar 2022To investigate the phenotypes, biochemical features and genotypes for 244 pedigrees with methylmalonic aciduria (MMA) in China, and to perform the prenatal genetic...
OBJECTIVES
To investigate the phenotypes, biochemical features and genotypes for 244 pedigrees with methylmalonic aciduria (MMA) in China, and to perform the prenatal genetic diagnosis by chorionic villus for these pedigrees.
MATERIALS AND METHODS
Gene analyses were performed for 244 pedigrees. There are 130 pedigrees, chorionic villus sampling was performed on the pregnant women to conduct the prenatal diagnosis.
RESULTS
Among 244 patients, 168 (68.9%) cases were combined methylmalonic aciduria and homocystinuria, 76 (31.1%) cases were isolated methylmalonic aciduria. All the patients were diagnosed with MMA by their clinical manifestation, elevated blood propionylcarnitine, propionylcarnitine to acetylcarnitine ratio, and/or urine/blood methylmalonic acid with or without homocysteine. MMACHC, MMUT, SUCLG1 and LMBRD1 gene variants were found in 236 (96.7%) pedigrees included 6 probands with only one heterozygous variant out of 244 cases. For the 130 pedigrees who received a prenatal diagnosis, 22 fetuses were normal, 69 foetuses were carriers of heterozygous variants, and the remaining 39 foetuses harboured compound heterozygous variants or homozygous variants. The follow-up results were consistent with the prenatal diagnosis.
CONCLUSION
The present study indicates genetic heterogeneity in MMA patients. Genetic analysis is a convenient method for prenatal diagnosis that will aid in avoiding the delivery of MMA patients.
Topics: Amino Acid Metabolism, Inborn Errors; China; Female; Genotype; Humans; Nucleocytoplasmic Transport Proteins; Oxidoreductases; Pedigree; Pregnancy; Prenatal Diagnosis
PubMed: 35361390
DOI: 10.1016/j.tjog.2022.02.017 -
Nature Metabolism Jan 2023Methylmalonic aciduria (MMA) is an inborn error of metabolism with multiple monogenic causes and a poorly understood pathogenesis, leading to the absence of effective...
Methylmalonic aciduria (MMA) is an inborn error of metabolism with multiple monogenic causes and a poorly understood pathogenesis, leading to the absence of effective causal treatments. Here we employ multi-layered omics profiling combined with biochemical and clinical features of individuals with MMA to reveal a molecular diagnosis for 177 out of 210 (84%) cases, the majority (148) of whom display pathogenic variants in methylmalonyl-CoA mutase (MMUT). Stratification of these data layers by disease severity shows dysregulation of the tricarboxylic acid cycle and its replenishment (anaplerosis) by glutamine. The relevance of these disturbances is evidenced by multi-organ metabolomics of a hemizygous Mmut mouse model as well as through identification of physical interactions between MMUT and glutamine anaplerotic enzymes. Using stable-isotope tracing, we find that treatment with dimethyl-oxoglutarate restores deficient tricarboxylic acid cycling. Our work highlights glutamine anaplerosis as a potential therapeutic intervention point in MMA.
Topics: Mice; Animals; Methylmalonyl-CoA Mutase; Glutamine; Multiomics; Metabolism, Inborn Errors
PubMed: 36717752
DOI: 10.1038/s42255-022-00720-8 -
Cell Reports Dec 2017Isolated methylmalonic acidemia/aciduria (MMA) is a devastating metabolic disorder with poor outcomes despite current medical treatments. Like other mitochondrial...
Isolated methylmalonic acidemia/aciduria (MMA) is a devastating metabolic disorder with poor outcomes despite current medical treatments. Like other mitochondrial enzymopathies, enzyme replacement therapy (ERT) is not available, and although promising, AAV gene therapy can be limited by pre-existing immunity and has been associated with genotoxicity in mice. To develop a new class of therapy for MMA, we generated a pseudoU-modified codon-optimized mRNA encoding human methylmalonyl-CoA mutase (hMUT), the enzyme most frequently mutated in MMA, and encapsulated it into biodegradable lipid nanoparticles (LNPs). Intravenous (i.v.) administration of hMUT mRNA in two different mouse models of MMA resulted in a 75%-85% reduction in plasma methylmalonic acid and was associated with increased hMUT protein expression and activity in liver. Repeat dosing of hMUT mRNA reduced circulating metabolites and dramatically improved survival and weight gain. Additionally, repeat i.v. dosing did not increase markers of liver toxicity or inflammation in heterozygote MMA mice.
Topics: Administration, Intravenous; Amino Acid Metabolism, Inborn Errors; Animals; Female; Genetic Therapy; Humans; Lipids; Liver; Male; Methylmalonyl-CoA Mutase; Mice; Nanoparticles; RNA, Messenger
PubMed: 29262333
DOI: 10.1016/j.celrep.2017.11.081 -
Frontiers in Neuroscience 2023Methylmalonic acidemia (MMA) is a genetic disease of abnormal organic acid metabolism, which is one of the important factors affecting the survival rate and quality of... (Review)
Review
Methylmalonic acidemia (MMA) is a genetic disease of abnormal organic acid metabolism, which is one of the important factors affecting the survival rate and quality of life of newborns or infants. Early detection and diagnosis are particularly important. The diagnosis of MMA mainly depends on clinical symptoms, newborn screening, biochemical detection, gene sequencing and neuroimaging diagnosis. The accumulation of methylmalonic acid and other metabolites in the body of patients causes brain tissue damage, which can manifest as various degrees of intellectual disability and severe neurological dysfunction. Neuroimaging examination has important clinical significance in the diagnosis and prognosis of MMA. This review mainly reviews the etiology, pathogenesis, and nervous system development, especially the neuroimaging features of MMA.
PubMed: 36777632
DOI: 10.3389/fnins.2023.1110942