Novel mutations in patients with McArdle disease by analysis of skeletal muscle mRNA

García‐Consuegra, Inés; Rubio, Juan Carlos Colomer; Nogales‐Gadea, Gisela; Bautista, Juan; Jiménez, Silvia; Cabello, Ana; Lucía, Alejandro; Andreu, Antoni L.; Arenas, Joaquı́n; Martín, Miguel

doi:10.1136/jmg.2008.059469

Cited by 21 publications

(24 citation statements)

References 19 publications

(36 reference statements)

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“…Transcriptomic studies have unveiled the pathogenic effect of some mutations such as intronic mutations, large deletions, and silent mutations [Fernandez‐Cadenas et al., ; Garcia‐Consuegra et al., ]. Mutations in the donor or acceptor splicing site of PYGM have been described; however, splicing alterations have only been characterized in some cases.…”

Section: Mutations and Polymorphismsmentioning

confidence: 99%

“…The c.1768+1G>A mutation in the donor splicing site of intron 14, causes a deletion of 67 bp at the 3′ region of exon 14 [Tsujino et al., b], and leads to an alteration in the open‐reading frame and a premature termination codon (PTC) in the sequence, p.V568AfsX16. The c.528‐8G>A mutation in the acceptor splicing sequence of intron 4 retains six nucleotides after splicing of intron 4, leading to the p.Q176_M177insVQ variation in the open‐reading frame [Garcia‐Consuegra et al., ]. Mutations in other introns have also been described, but their effect at the transcript level has not been studied yet.…”

Section: Mutations and Polymorphismsmentioning

confidence: 99%

“…Mutations in other introns have also been described, but their effect at the transcript level has not been studied yet. Transcriptomic studies have also revealed deletion of the full exon 17 in the transcript sequence of one patient [Garcia‐Consuegra et al., ]. Interestingly, some silent mutations that do not alter the amino acid sequence, that is, c.645G>A (p.K215K), c.1827G>A (p.K609K), and c.2430C>T (p.G810G), have been demonstrated to affect splicing [Fernandez‐Cadenas et al., ; Garcia‐Consuegra et al., ].…”

Section: Mutations and Polymorphismsmentioning

confidence: 99%

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McArdle Disease: Update of Reported Mutations and Polymorphisms in thePYGMGene

et al. 2015

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McArdle disease is an autosomal-recessive disorder caused by inherited deficiency of the muscle isoform of glycogen phosphorylase (or "myophosphorylase"), which catalyzes the first step of glycogen catabolism, releasing glucose-1-phosphate from glycogen deposits. As a result, muscle metabolism is impaired, leading to different degrees of exercise intolerance. Patients range from asymptomatic to severely affected, including in some cases, limitations in activities of daily living. The PYGM gene codifies myophosphoylase and to date 147 pathogenic mutations and 39 polymorphisms have been reported. Exon 1 and 17 are mutational hot-spots in PYGM and 50% of the described mutations are missense. However, c.148C>T (commonly known as p.R50X) is the most frequent mutation in the majority of the studied populations. No genotype-phenotype correlation has been reported and no mutations have been described in the myophosphorylase domains affecting the phosphorylated Ser-15, the 280's loop, the pyridoxal 5'-phosphate, and the nucleoside inhibitor binding sites. A newly generated knock-in mouse model is now available, which renders the main clinical and molecular features of the disease. Well-established methods for diagnosing patients in laboratories around the world will shorten the frequent ∼20-year period stretching from first symptoms appearance to the genetic diagnosis.

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Section: Mutations and Polymorphismsmentioning

confidence: 99%

Section: Mutations and Polymorphismsmentioning

confidence: 99%

Section: Mutations and Polymorphismsmentioning

confidence: 99%

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McArdle Disease: Update of Reported Mutations and Polymorphisms in thePYGMGene

et al. 2015

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“…35 Spanish McArdle patients (P1–P35), some of them previously characterized by molecular techniques [13], [14], [15], [16] were included in the study (Table 1). To avoid differences due to lower muscle training compared with non-patients, 7 healthy volunteers with sedentary life-style habits were used as controls (C1–C7).…”

Section: Methodsmentioning

confidence: 99%

A Transcriptomic Approach to Search for Novel Phenotypic Regulators in McArdle Disease

et al. 2012

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McArdle disease is caused by lack of glycogen phosphorylase (GP) activity in skeletal muscle. Patients experience exercise intolerance, presenting as early fatigue and contractures. In this study, we investigated the effects produced by a lack of GP on several genes and proteins of skeletal muscle in McArdle patients. Muscle tissue of 35 patients and 7 healthy controls were used to identify abnormalities in the patients' transcriptomic profile using low-density arrays. Gene expression was analyzed for the influence of variables such as sex and clinical severity. Differences in protein expression were studied by immunoblotting and 2D electrophoresis analysis, and protein complexes were examined by two-dimensional, blue native gel electrophoresis (BN-PAGE). A number of genes including those encoding acetyl-coA carboxylase beta, m-cadherin, calpain III, creatine kinase, glycogen synthase (GS), and sarcoplasmic reticulum calcium ATPase 1 (SERCA1), were found to be downregulated in patients. Specifically, compared to controls, GS and SERCA1 proteins were reduced by 50% and 75% respectively; also, unphosphorylated GS and SERCA1 were highly downregulated. On BN-PAGE analysis, GP was present with GS in two muscle protein complexes. Our findings revealed some issues that could be important in understanding the physiological consequences of McArdle disease: (i) SERCA1 downregulation in patients could result in impaired calcium transport in type II (fast-twitch) muscle fibers, leading to early fatigability during exercise tasks involving type II fibers (which mostly use glycolytic metabolism), i.e. isometric exercise, lifting weights or intense dynamic exercise (stair climbing, bicycling, walking at a very brisk pace), (ii) GP and GS were found together in two protein complexes, which suggests a new regulatory mechanism in the activity of these glycogen enzymes.

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“…reported in a single patient or in the members of the same family [9]. Moreover, studies on skeletal muscle cDNA resulted in: (i) the identification of mutations that genomic direct analysis failed to detect, and (ii) understanding the effect of PYGM mutations in gene expression [10]. An RNA surveillance mechanism known as ‘nonsense mediated mRNA decay’ (NMD), reduces the mRNA levels of those transcripts that contain nonsense and frameshift mutations [11].…”

Section: Introductionmentioning

confidence: 99%

Expression of Glycogen Phosphorylase Isoforms in Cultured Muscle from Patients with McArdle's Disease Carrying the p.R771PfsX33 PYGM Mutation

et al. 2010

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BackgroundMutations in the PYGM gene encoding skeletal muscle glycogen phosphorylase (GP) cause a metabolic disorder known as McArdle's disease. Previous studies in muscle biopsies and cultured muscle cells from McArdle patients have shown that PYGM mutations abolish GP activity in skeletal muscle, but that the enzyme activity reappears when muscle cells are in culture. The identification of the GP isoenzyme that accounts for this activity remains controversial.Methodology/Principal FindingsIn this study we present two related patients harbouring a novel PYGM mutation, p.R771PfsX33. In the patients' skeletal muscle biopsies, PYGM mRNA levels were ∼60% lower than those observed in two matched healthy controls; biochemical analysis of a patient muscle biopsy resulted in undetectable GP protein and GP activity. A strong reduction of the PYGM mRNA was observed in cultured muscle cells from patients and controls, as compared to the levels observed in muscle tissue. In cultured cells, PYGM mRNA levels were negligible regardless of the differentiation stage. After a 12 day period of differentiation similar expression of the brain and liver isoforms were observed at the mRNA level in cells from patients and controls. Total GP activity (measured with AMP) was not different either; however, the active GP activity and immunoreactive GP protein levels were lower in patients' cell cultures. GP immunoreactivity was mainly due to brain and liver GP but muscle GP seemed to be responsible for the differences.Conclusions/SignificanceThese results indicate that in both patients' and controls' cell cultures, unlike in skeletal muscle tissue, most of the protein and GP activities result from the expression of brain GP and liver GP genes, although there is still some activity resulting from the expression of the muscle GP gene. More research is necessary to clarify the differential mechanisms of metabolic adaptations that McArdle cultures undergo in vitro.

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Novel mutations in patients with McArdle disease by analysis of skeletal muscle mRNA

Abstract: Our results indicate that skeletal muscle cDNA studies in "genetic manifesting heterozygous" patients with McArdle disease are prone to identify their second mutant allele.

Cited by 21 publications

References 19 publications

McArdle Disease: Update of Reported Mutations and Polymorphisms in thePYGMGene

McArdle Disease: Update of Reported Mutations and Polymorphisms in thePYGMGene

A Transcriptomic Approach to Search for Novel Phenotypic Regulators in McArdle Disease

Expression of Glycogen Phosphorylase Isoforms in Cultured Muscle from Patients with McArdle's Disease Carrying the p.R771PfsX33 PYGM Mutation

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