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Abstract
Metabolic myopathies are inborn errors of metabolism that result in impaired energy production due to defects in glycogen, lipid, mitochondrial, and possibly adenine nucleotide metabolism. Fatty acid oxidation defects (FAOD), glycogen storage disease, and mitochondrial myopathies represent the 3 main groups of disorders, and some consider myoadenylate deaminase (AMPD1 deficiency) to be a metabolic myopathy. Clinically, a variety of neuromuscular presentations are seen at different ages of life. Newborns and infants commonly present with hypotonia and multisystem involvement (liver and brain), whereas onset later in life usually presents with exercise intolerance with or without progressive muscle weakness and myoglobinuria. In general, the glycogen storage diseases result in high-intensity exercise intolerance, whereas the FAODs and the mitochondrial myopathies manifest predominately during endurance-type activity or under fasted or other metabolically stressful conditions. The clinical examination is often normal, and testing requires various combinations of exercise stress testing, serum creatine kinase activity and lactate concentration determination, urine organic acids, muscle biopsy, neuroimaging, and specific genetic testing for the diagnosis of a specific metabolic myopathy. Prenatal screening is available in many countries for several of the FAODs through liquid chromatography-tandem mass spectrometry. Early identification of these conditions with lifestyle measures, nutritional intervention, and cofactor treatment is important to prevent or delay the onset of muscle weakness and to avoid potential life-threatening complications such as rhabdomyolysis with resultant renal failure or hepatic failure. This article will review the key clinical features, diagnostic tests, and treatment recommendations for the more common metabolic myopathies, with an emphasis on mitochondrial myopathies.
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Kinugawa T, Ogino K, Kato M, Kato T, Osaki S, Endo A, Igawa O, Hisatome I, Shigemasa C, Holmes EW. Altered purine and glycogen metabolism in skeletal muscle during exercise in patients with heart failure. Metabolism 1999; 48:484-8. [PMID: 10206442 DOI: 10.1016/s0026-0495(99)90108-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Plasma levels of ammonia and hypoxanthine (HX) can be indices of purine nucleotide degradation. The present study determined if patients with heart failure (HF) have altered exercise plasma ammonia and HX levels relative to the peak work rate performed. Blood lactate, plasma ammonia, and plasma HX levels were measured in 59 patients with HF (New York Heart Association [NYHA] classes I:20, II:21, and III:18) and 21 controls at rest and after a maximal cardiopulmonary exercise test. The peak work rate (normal and NYHA I, II, and III, 163+/-11, 152+/-9, 94+/-5, and 69+/-5 W) and peak oxygen uptake ([VO2] 32.3+/-1.7, 25.1+/-0.9, 18.6+/-0.5, and 14.1+/-0.6 mL/min/kg) decreased as the NYHA functional class increased. The increment from rest to peak exercise (delta) for lactate ([(delta)lactate] 6.1+/-0.3, 4.8+/-0.4, 4.6+/-0.3, and 2.9+/-0.3 mmol/L), (delta)ammonia (132+/-14, 119+/-20, 94+/-13, and 32+/-6 microg/dL), and (delta)HX (33.5+/-3.4, 24.9+/-4.7, 20.6+/-3.0, and 9.9+/-1.2 micromol/L) was progressively smaller as HF worsened. The ratio for (delta)lactate to peak work rate (0.037+/-0.003, 0.032+/-0.004, 0.049+/-0.003, and 0.042+/-0.005) was higher in classes II to III HF, while the ratio for (delta)ammonia to peak work rate (0.81+/-0.14, 0.78+/-0.16, 0.99+/-0.11, and 0.47+/-0.11) was significantly lower in class III HF. In summary, patients with HF exhibited a smaller ammonia response with a higher lactate response to exercise when normalized with the peak work rate. These results suggest there may be an altered purine and glycogen metabolism during exercise in skeletal muscle in patients with HF.
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Affiliation(s)
- T Kinugawa
- First Department of Internal Medicine, Tottori University School of Medicine, Yonago, Japan
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Fabrizi GM, Lodi R, D'Ettorre M, Malandrini A, Cavallaro T, Rimoldi M, Zaniol P, Barbiroli B, Guazzi G. Autosomal dominant limb girdle myopathy with ragged-red fibers and cardiomyopathy. A pedigree study by in vivo 31P-MR spectroscopy indicating a multisystem mitochondrial defect. J Neurol Sci 1996; 137:20-7. [PMID: 9120483 DOI: 10.1016/0022-510x(95)00321-r] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We describe a late-onset autosomal dominant limb girdle myopathy, associated with dilated cardiomyopathy and mental deterioration. In two affected members of the pedigree with histochemical (ragged-red and cytocrome c oxidase - negative fibers) and ultrastructural abnormalities of muscle mitochondria, in vivo muscle phosphorus MR spectroscopy disclosed a slow rate of phosphocreatine resynthesis after exercise. Brain phosphorus MR spectroscopy revealed a defect of the energy metabolism in the two patients and in a third asymptomatic member, as shown by a significantly low phosphocreatine, increased ADP and decreased phosphorylation potential. Molecular analysis of muscle mitochondrial DNA failed to reveal any known mutation, including multiple deletions of the mtDNA which have been associated with some autosomal dominant mitochondrial diseases. The multisystem clinical involvement, the presence of ragged-red fibers and the alterations revealed by in vivo brain and muscle 31P-MRS suggest that this limb-girdle syndrome represents an unusual phenotype of mitochondrial cytopathy.
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Affiliation(s)
- G M Fabrizi
- Istituto di Scienze Neurologiche, Universitat di Siena, Policlinico Le Scotte, Italy
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Malandrini A, Scarpini C, Fabrizi GM, Parrotta E, Salvadori C, Guazzi GC. Early-onset benign limb-girdle myopathy with contractures and facial involvement affecting a father and daughter. J Neurol Sci 1995; 132:195-200. [PMID: 8543948 DOI: 10.1016/0022-510x(95)00156-v] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We describe a father and daughter with early-onset benign limb-girdle myopathy and contractures of elbows and hands, resembling Bethlem disease. Muscle biopsy showed a pattern of dystrophy with non specific mitochondrial changes. In both patients there was unusual facial muscle weakness. We discuss the nosologic position of Bethlem myopathy and suggest that facial involvement may be an additional feature of this disease.
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Affiliation(s)
- A Malandrini
- Institute of Neurological Sciences, University of Siena, Italy
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Morisaki T, Gross M, Morisaki H, Pongratz D, Zöllner N, Holmes EW. Molecular basis of AMP deaminase deficiency in skeletal muscle. Proc Natl Acad Sci U S A 1992; 89:6457-61. [PMID: 1631143 PMCID: PMC49520 DOI: 10.1073/pnas.89.14.6457] [Citation(s) in RCA: 148] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
AMP deaminase (AMPD; EC 3.5.4.6) is encoded by a multigene family in mammals. The AMPD1 gene is expressed at high levels in skeletal muscle, where this enzyme is thought to play an important role in energy metabolism. Deficiency of AMPD activity in skeletal muscle is associated with symptoms of a metabolic myopathy. Eleven unrelated individuals with AMPD deficiency were studied, and each was shown to be homozygous for a mutant allele characterized by a C----T transition at nucleotide 34 (codon 12 in exon 2) and at nucleotide 143 (codon 48 in exon 3). The C----T transition at codon 12 results in a nonsense mutation predicting a severely truncated AMPD peptide. Consistent with this prediction, no immunoreactive AMPD1 peptide is detectable in skeletal muscle of these patients. This mutant allele is found in 12% of Caucasians and 19% of African-Americans, whereas none of the 106 Japanese subjects surveyed has this mutant allele. We conclude from these studies that this mutant allele is present at a sufficiently high frequency to account for the 2% reported incidence of AMPD deficiency in muscle biopsies. The restricted distribution and high frequency of this doubly mutated allele suggest it arose in a remote ancestor of individuals of Western European descent.
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Affiliation(s)
- T Morisaki
- Department of Medicine, Duke University Medical Center, Durham, NC 27706
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Abstract
Myoadenylate deaminase (MAD) is the rate-limiting enzyme in the purine nucleotide cycle which is biochemically linked to glycolysis and the citric cycle and thereby providing energy during intense muscular activity. In muscle fibers, myoadenylate deaminase operates at considerably higher activity levels than in other organs. First detected using enzyme-histochemical methods, it now appears that deficiency of myoadenylate deaminase is one of the most frequent enzyme defects in muscle. The primary defect may occur as an isolated nosological entity or not infrequently it is also associated with a large spectrum of different neuromuscular conditions. It seems to be the primary unassociated MAD deficiency that has recently become amenable to successful treatment with D-ribose in high doses. Secondary MAD deficiency may occur in muscle fibers and muscles that have undergone structural damage as seen, for instance, in polymyositis, muscular dystrophy, and denervation. The wealth of biochemical, morphological, and clinical data that has accumulated since the discovery of MAD deficiency during the past decade provides nosological significance of MAD deficiency as a real entity.
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Affiliation(s)
- H H Goebel
- Abteilung für Neuropathologie der Universität, Mainz
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Mercelis R, Martin JJ, de Barsy T, Van den Berghe G. Myoadenylate deaminase deficiency: absence of correlation with exercise intolerance in 452 muscle biopsies. J Neurol 1987; 234:385-9. [PMID: 3655841 DOI: 10.1007/bf00314082] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
A histochemical assay was routinely performed of myoadenylate deaminase (MAD) in muscle biopsy specimens. MAD was absent in 13 cases, i.e. 2.9% of the specimens. In 10 cases the deficiency was confirmed biochemically. The diagnoses in the 13 patients were: polyneuropathy (n = 5), infantile spinal muscular atrophy (n = 3), congenital myopathy with type 2 fibre atrophy, facioscapulohumeral myopathy, polymyositis, myotonic dystrophy and hyperornithinaemia with gyrate atrophy of the retina. In contrast, 35 unrelated patients presenting with exercise-related muscle cramps or pains showed normal histochemical MAD activity. The biopsy specimens in all of these patients were essentially normal and in none of them was the diagnosis of a neuromuscular disease made. The results failed to confirm the association of MAD deficiency with aches, cramps and pains or exertional myalgia.
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Affiliation(s)
- R Mercelis
- Department of Neurology, University Hospital, Antwerp, Belgium
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Valen PA, Nakayama DA, Veum J, Sulaiman AR, Wortmann RL. Myoadenylate deaminase deficiency and forearm ischemic exercise testing. ARTHRITIS AND RHEUMATISM 1987; 30:661-8. [PMID: 3606685 DOI: 10.1002/art.1780300609] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Myoadenylate deaminase (MADA) deficiency has been associated with symptoms of postexertional aches, cramps, weakness, and skeletal muscle dysfunction. Measurement of plasma lactate and ammonia concentrations after forearm ischemic exercise has been suggested as a screening test for this disorder. We performed forearm ischemic tests on 3 patients with histochemically defined MADA deficiency and 13 healthy control subjects, in a standardized fashion. Our results demonstrated that subject effort and/or performance during the exercise portion of testing is a critical variable. In addition to lactate and ammonia, plasma purine compounds (adenosine, inosine, and hypoxanthine) were measured. The finding of decreased purine release after exercise in MADA-deficient patients compared with that in normal individuals increases the specificity of the test and supports the hypothesis that disordered purine metabolism occurs in MADA deficiency.
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Sinkeler SP, Wevers RA, Joosten EM, Binkhorst RA, Oei LT, Van't Hof MA, De Haan AF. Improvement of screening in exertional myalgia with a standardized ischemic forearm test. Muscle Nerve 1986; 9:731-7. [PMID: 3785284 DOI: 10.1002/mus.880090809] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
An ischemic forearm test with simultaneous measurement of both lactate and ammonia can be used as a screening method for myoadenylate deaminase deficiency (MADD) and for various glyco(geno)lytic defects. A standardized and a nonstandardized test have been compared in a group of 186 patients with exertional myalgia. Standardization of the ischemic forearm test has led to greater yields of both lactate and ammonia in venous return blood of patients and controls. The sensitivity of the proposed test procedure in detecting MADD patients was 100%, whereas the specificity amounted to 98.8% among exertional myalgia patients.
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Coleman RA, Stajich JM, Pact VW, Pericak-Vance MA. The ischemic exercise test in normal adults and in patients with weakness and cramps. Muscle Nerve 1986; 9:216-21. [PMID: 3702911 DOI: 10.1002/mus.880090305] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Data from 23 normal men and women were used to derive 95% confidence limits for maximum changes in ammonia and lactate values following ischemic forearm exercise. Most normal subjects raised serum lactate and ammonia concentrations more than 20 mg/dl and 100 micrograms/dl, respectively, over baseline values. No significant correlations were found among age, sex, duration of exercise, or estimate of work performed and the maximum ammonia and lactate values achieved. When 70 patients with complaints of weakness, fatigue, or cramps were evaluated, the ischemic exercise test identified 5 patients who proved to have defects in glycolysis or purine metabolism. The test also distinguished those patients with type III glycogen storage disease who lacked debrancher enzyme activity in muscle.
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Lally EV, Friedman JH, Kaplan SR. Progressive myalgias and polyarthralgias in a patient with myoadenylate deaminase deficiency. ARTHRITIS AND RHEUMATISM 1985; 28:1298-302. [PMID: 4063004 DOI: 10.1002/art.1780281115] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Abstract
The most frequent metabolic myopathies of children and adults (glycogenoses; neutral fat myopathies; "mitochondrial" myopathies) are reviewed. In glycogenoses and neutral fat myopathies the most prominent histological feature is represented by a vacuolation of muscle fibres, vacuoles being filled with glycogen or neutral fat. Enzyme defects of glycogenoses are known. In some neutral fat myopathies, an involvement of carnitine metabolism can be found; in many other cases, biochemical investigations have failed to identify the enzyme defect(s), or have demonstrated the contemporaneous involvement of mitochondria ("mitochondrial" myopathy). The large group of "mitochondrial" myopathies is built up of many heterogeneous polygenetic syndromes, the appearance of which signalises only an impaired mitochondrial function due to underlying biochemical defect(s). In these cases, accumulations of mitochondria in muscle fibres, easily recognisable with trichrome stain ("ragged-red fibres") may be found. These mitochondria usually present very peculiar ultrastructural changes ("paracrystalline inclusions"). One of the leading clinical symptoms of metabolic myopathies is represented by myoglobinuria. In every case of "idiopathic" rhabdomyolysis, a metabolic myopathy should hence be suspected. The negative result of histological and enzymehistochemical investigations, does not exclude the presence of a metabolic disorder, however. Research in this field requires a very strong cooperation between morphologists and biochemists. Future therapeutical approaches can in fact only come from and through biochemistry.
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Abstract
Myoadenylate deaminase (MADA) is an enzyme which participates in the purine nucleotide cycle necessary for energy production in human skeletal muscle. Approximately 35 patients with deficiency of this enzyme have been reported; one-half experienced their initial difficulties in childhood. Children with "primary" MADA deficiency typically have symptoms including muscle cramps, stiffness, and post-exercise myalgia and weakness. In "secondary" MADA deficiency, the clinical findings have been variable with delayed motor development, hypotonia, cardiomyopathy, delayed speech development, and generalized weakness. In most cases creatine kinase determinations, nerve conduction velocity studies, and routine muscle histopathology have been normal. Diagnosis has been established by demonstrating an absence of MADA activity by either direct muscle enzyme assay or histochemical staining. In this report we describe a 12-year-old boy with primary MADA deficiency and contrast his symptoms with those of previously described pediatric patients.
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Affiliation(s)
- S Ashwal
- Department of Pediatrics, Loma Linda University School of Medicine, CA 92350
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Sabina RL, Swain JL, Olanow CW, Bradley WG, Fishbein WN, DiMauro S, Holmes EW. Myoadenylate deaminase deficiency. Functional and metabolic abnormalities associated with disruption of the purine nucleotide cycle. J Clin Invest 1984; 73:720-30. [PMID: 6707201 PMCID: PMC425074 DOI: 10.1172/jci111265] [Citation(s) in RCA: 109] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
To assess the role of the purine nucleotide cycle in human skeletal muscle function, we evaluated 10 patients with AMP deaminase deficiency (myoadenylate deaminase deficiency; MDD). 4 MDD and 19 non-MDD controls participated in an exercise protocol. The latter group was composed of a patient cohort (n = 8) exhibiting a constellation of symptoms similar to those of the MDD patients, i.e., postexertional aches, cramps, and pains; as well as a cohort of normal, unconditioned volunteers (n = 11). The individuals with MDD fatigued after performing only 28% as much work as their non-MDD counterparts. Muscle biopsies were obtained from the four MDD patients and the eight non-MDD patients at rest and following exercise to the point of fatigue. Creatine phosphate content fell to a comparable extent in the MDD (69%) and non-MDD (52%) patients at the onset of fatigue. Following exercise the 34% decrease in ATP content of muscle from the non-MDD subjects was significantly greater than the 6% decrease in ATP noted in muscle from the MDD patients (P = 0.048). Only one of four MDD patients had a measurable drop in ATP compared with seven of eight non-MDD patients. At end-exercise the muscle content of inosine 5'-monophosphate (IMP), a product of AMP deaminase, was 13-fold greater in the non-MDD patients than that observed in the MDD group (P = 0.008). Adenosine content of muscle from the MDD patients increased 16-fold following exercise, while there was only a twofold increase in adenosine content of muscle from the non-MDD patients (P = 0.028). Those non-MDD patients in whom the decrease in ATP content following exercise was measurable exhibited a stoichiometric increase in IMP, and total purine content of the muscle did not change significantly. The one MDD patient in whom the decrease in ATP was measurable, did not exhibit a stoichiometric increase in IMP. Although the adenosine content increased 13-fold in this patient, only 48% of the ATP catabolized could be accounted for by the combined increases of adenosine, inosine, hypoxanthine, and IMP. Studies performed in vitro with muscle samples from seven MDD and seven non-MDD subjects demonstrated that ATP catabolism was associated with a fivefold greater increase in IMP in non-MDD muscle. There were significant increases in AMP and ADP content of the muscle from MDD patients following ATP catabolism in vitro, while there was no detectable increase in AMP or ADP in non-MDD muscle. Adenosine content of MDD muscle increased following ATP catabolism, but there was no detectable increase in adenosine content of non-MDD muscle following ATP catabolism in vitro. These studies demonstrate that AMP deaminase deficiency leads to reduced entry of adenine nucleotides into the purine nucleotide cycle during exercise. We postulate that the resultant disruption of the purine nucleotide cycle accounts for the muscle dysfunction observed in these patients.
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Fishbein WN. Human myoadenylate deaminase deficiency. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1984; 165 Pt A:77-84. [PMID: 6720420 DOI: 10.1007/978-1-4684-4553-4_14] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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