Lipid-storage myopathy with glycogen storage disease gene mutations mimicking polymyositis: a case report and review of the literature

A 26-year-old Asian woman with persistent muscle weakness was diagnosed with polymyositis based on biopsy findings at another hospital 11 years ago. However, her symptoms fluctuated repeatedly under treatment with prednisone and immunosuppressive agents, and worsened 2 months prior to the current presentation. A second muscle biopsy suggested metabolic myopathy, and genetic testing revealed a novel c.1074C > T variant in the glycogen synthase 1 gene (GYS1), which is implicated in muscle glycogen storage disease type 0. However, no abnormalities in glycogen deposition were found by biopsy; rather, muscle fibers exhibited large intracellular lipid droplets. Furthermore, muscle strength was greatly restored and circulating levels of creatine kinase indicative of muscle degeneration greatly reduced by vitamin B2 treatment. Therefore, the final diagnosis was lipid storage myopathy.     

Anesthesia considerations in a patient with mcArdle disease: a case report

A patient with McArdle disease underwent bowel surgery with general anesthesia and was successfully managed. McArdle disease is a rare skeletal muscle disorder affecting approximately 1 in 100,000 people. McArdle disease, also known as type V glycogen storage disease, is an autosomal recessive inherited condition caused by a missing or nonfunctioning enzyme called myophosphorylase C. This phosphorylase is the enzyme responsible for making glucose for energy. Individuals suffering from McArdle disease have muscles that cannot properly metabolize energy and may experience fatigue and failure during strenuous activities. When a patient with McArdle disease presents for any surgical procedure, a variety of anesthesia implications should be discussed and incorporated into the overall management of his or her care. Careful attention to adequate fluid management, appropriate neuromuscular blockade choices, normothermia maintenance, normoglycemia maintenance, blood pressure monitoring, and maintaining malignant hyperthermia precautions is critical to providing safe anesthesia to this unique patient population.     

Clinical Presentation and Management of Severe Acute Renal Failure in McArdle Disease

McArdle disease, also known as glycogen storage disease type V, is an autosomal recessive disease due to the absence of myophosphorylase activity, leading to the complete disruption of glycogen breakdown in muscles. We present a rare case of a Caucasian male, aged 26 years, who developed rhabdomyolysis-induced acute renal failure and uremic encephalopathy. Neurological examination and histopathological studies supported the diagnosis of McArdle disease. The severity of his symptoms necessitated urgent hemodialysis, upon which the patient reported improvement in status. Acute renal failure in McArdle disease usually resolves with supportive treatment and maintenance of regular physical activity. Nevertheless, in more severe cases, intensive care with urgent hemodialysis may be needed. A multidisciplinary approach is necessary for the adequate management of similar cases.     

Creatine supplementation increases glycogen storage but not GLUT-4 expression in human skeletal muscle

It has been speculated that creatine supplementation affects muscle glucose metabolism in humans by increasing muscle glycogen storage and up-regulating GLUT-4 protein expression. In the present study, we assessed the effects of creatine loading and prolonged supplementation on muscle glycogen storage and GLUT-4 mRNA and protein content in humans. A total of 20 subjects participated in a 6-week supplementation period during which creatine or a placebo was ingested. Muscle biopsies were taken before and after 5 days of creatine loading (20 g.day(-1)) and after 6 weeks of continued supplementation (2 g.day(-1)). Fasting plasma insulin concentrations, muscle creatine, glycogen and GLUT-4 protein content as well as GLUT-4, glycogen synthase-1 (GS-1) and glycogenin-1 (Gln-1) mRNA expression were determined. Creatine loading significantly increased total creatine, free creatine and creatine phosphate content with a concomitant 18 +/- 5% increase in muscle glycogen content (P<0.05). The subsequent use of a 2 g.day(-1) maintenance dose for 37 days did not maintain total creatine, creatine phosphate and glycogen content at the elevated levels. The initial increase in muscle glycogen accumulation could not be explained by an increase in fasting plasma insulin concentration, muscle GLUT-4 mRNA and/or protein content. In addition, neither muscle GS-1 nor Gln-1 mRNA expression was affected. We conclude that creatine ingestion itself stimulates muscle glycogen storage, but does not affect muscle GLUT-4 expression.     

Molecular mechanisms of McArdle''s disease (muscle glycogen phosphorylase deficiency). RNA and DNA analysis.

Lack of muscle glycogen phosphorylase activity leads to McArdle's disease, a rare metabolic myopathy. To investigate its molecular basis at the nucleic acid level, we isolated muscle phosphorylase cDNA clones from a human cDNA library in Escherichia coli plasmid pBR 322. Subcloning of one insertion of M13 bacteriophage permitted its definite identification by sequencing. Northern blot experiments revealed one specific messenger RNA of 3.4 kilobases found uniquely in tissues expressing muscle phosphorylase. We show that McArdle's disease exhibits a molecular heterogeneity at the messenger RNA level. In eight unrelated cases of McArdle's disease in which no inactive proteins had been detected, we assayed muscle biopsies for phosphorylase mRNA by Northern blotting. In five cases, no muscle phosphorylase mRNA could be detected, while in three other cases, normal length mRNA was present in lower amounts. Moreover, Southern blot analysis of DNA isolated from white blood cells in four McArdle patients revealed no major deletion or rearrangements of the phosphorylase gene as compared with controls.     

Correction of glycogen storage disease type II by an adeno-associated virus vector containing a muscle-specific promoter.

Glycogen storage disease type II (Pompe disease) causes death in infancy from cardiorespiratory failure due to acid alpha-glucosidase (GAA; acid maltase) deficiency. An AAV2 vector pseudotyped as AAV6 (AAV2/6 vector) transiently expressed high-level human GAA in GAA-knockout (GAA-KO) mice without reducing glycogen storage; however, in immunodeficient GAA-KO/SCID mice the AAV2/6 vector expressed high-level GAA and reduced the glycogen content of the injected muscle for 24 weeks. A CD4+/CD8+ lymphocytic infiltrate was observed in response to the AAV2/6 vector in immunocompetent GAA-KO mice. When a muscle-specific creatine kinase promoter was substituted for the CB promoter (AAV-MCKhGAApA), that AAV2/6 vector expressed high-level GAA and reduced glycogen content in immunocompetent GAA-KO mice. Muscle-restricted expression of hGAA provoked only a humoral (not cellular) immune response. Intravenous administration of a high number of particles of AAV-MCKhGAApA as AAV2/7 reduced the glycogen content of the heart and skeletal muscle and corrected individual myofibers in immunocompetent GAA-KO mice 24 weeks postinjection. In summary, persistent correction of muscle glycogen content was achieved with an AAV vector containing a muscle-specific promoter in GAA-KO mice, and this approach should be considered for muscle-targeted gene therapy in Pompe disease.     

Muscle-specific overexpression of lipoprotein lipase causes a severe myopathy characterized by proliferation of mitochondria and peroxisomes in transgenic mice.

In extrahepatic tissues lipoprotein lipase (LPL) hydrolyzes triglycerides thereby generating FFA for tissue uptake and metabolism. To study the effects of increased FFA uptake in muscle tissue, transgenic mouse lines were generated with a human LPL minigene driven by the promoter of the muscle creatine kinase gene. In these mice human LPL was expressed in skeletal muscle and cardiac muscle, but not in other tissues. In proportion to the level of LPL overexpression, decreased plasma triglyceride levels, elevated FFA uptake by muscle tissue, weight loss, and premature death were observed in three independent transgenic mouse lines. The animals developed a severe myopathy characterized by muscle fiber degeneration, fiber atrophy, glycogen storage, and extensive proliferation of mitochondria and peroxisomes. This degree of proliferation suggests that FFA play an important role in the biogenesis of these organelles. Our experiments indicate that LPL is rate limiting for the supply of muscle tissue with triglyceride-derived FFA. Improper regulation of muscle LPL can lead to major pathological changes and may be important in the pathogenesis of some human myopathies. Muscle-specific LPL transgenic mouse lines will serve as a useful animal model for the investigation of myopathies and the biogenesis of mitochondria and peroxisomes.     

Replacing acid alpha-glucosidase in Pompe disease: recombinant and transgenic enzymes are equipotent, but neither completely clears glycogen from type II muscle fibers.

Pompe disease (type II glycogen storage disease) is an autosomal recessive disorder caused by a deficiency of lysosomal acid alpha-glucosidase (GAA) leading to the accumulation of glycogen in the lysosomes primarily in cardiac and skeletal muscle. The recombinant human GAA (rhGAA) is currently in clinical trials for enzyme replacement therapy of Pompe disease. Both clinical data and the results of preclinical studies in our knockout model of this disease show that rhGAA is much more effective in resolving the cardiomyopathy than the skeletal muscle myopathy. By contrast, another form of human GAA--transgenic enzyme constitutively produced in liver and secreted into the bloodstream of knockout mice (Gaa-/-)--completely prevented both cardiac and skeletal muscle glycogen accumulation. In the experiments reported here, the transgenic enzyme was much less efficient when delivered to skeletal muscle after significant amounts of glycogen had already accumulated. Furthermore, the transgenic enzyme and the rhGAA have similar therapeutic effects, and both efficiently clear glycogen from cardiac muscle and type I muscle fibers, but not type II fibers. Low abundance of proteins involved in endocytosis and trafficking of lysosomal enzymes combined with increased autophagy in type II fibers may explain the resistance to therapy.     

Alcoholic skeletal myopathy, a clinical and pathological study

One hundred and fifty-one inpatients with a history of chronic heavy alcohol intake were examined for evidence of muscle disease. Ninety-two patients (60 per cent) had histologically abnormal biopsies of the quadriceps muscle. The most common abnormality, which was often severe, was type II muscle fibre atrophy. Seven patients (5 per cent) had histological evidence of acute myopathy, one of whom presented with the full clinical picture of acute rhabdomyolysis. Twenty-three patients had cirrhosis, 36 were significantly malnourished and 98 had evidence of a peripheral neuropathy. None of these features, however, were sufficient to account for the muscle abnormalities. There was no clear relationship between musculo-skeletal symptoms and muscle biopsy histology. Serum creatine kinase activity was elevated in only 23 subjects and was an insensitive indicator of subclinical acute myopathy and of chronic alcoholic myopathy. Follow-up studies after abstinence from alcohol invariably showed both objective and subjective improvement of muscle function - often in the absence of any clinical recovery from the peripheral neuropathy. Continued alcohol consumption was accompanied by persistence and often deterioration of muscle fibre atrophy. It is concluded that chronic skeletal myopathy is a frequent consequence of alcohol abuse and may result from a direct toxic effect of ethanol on muscle fibres.     

5例晚发型糖原贮积症Ⅱ型患者的临床分析

目的:探讨糖原贮积症的临床病理特征。方法:对5例晚发型糖原贮积症患者的临床、病理资料进行回顾性分析,并进行病理形态学、特殊染色及电镜观察。结果:本组5例患者体格检查显示四肢远近端、躯体肌肉均匀萎缩;四肢肌张力不同程度降低,颈肌力量稍差,Gewer征阳性。实验室检查血清肌酸激酶(CK)均有不同程度升高。肌电图显示多呈肌源性损害表现,其中3例伴强直样放电及飞机俯冲声。光镜下肌纤维束膜基本完整,染色不均,肌原纤维结构破坏,肌浆内空泡形成,部分肌纤维内见大量颗粒状物质堆积,HE染色表现为颗粒蓝染,GMR红染,PAS深染,NADH-TR染色显示脱失。电镜观察部分肌原纤维间见糖原颗粒聚集,聚集的糖原颗粒部分游离分散,但大多形成膜包绕的空腔结构。结论:糖原贮积症Ⅱ型是一种罕见的进展性溶酶体贮积病,由位于第17号染色体上的酸性α-葡糖苷酶(GAA)基因突变所致,呈常染色体隐性遗传。晚发型GSDⅡ型患者临床多隐匿起病,对于疑似患者,可根据病理形态学主要受累肌肉内糖原沉积并结合电镜观察及临床表现而得出,确诊及分型则需依靠GAA酶的测定或缺陷酶热点基因突变分析。人重组α-葡糖苷酶治疗该病,使患者预后显著改善。     

抗HMGCR/SRP抗体阳性的特发性炎性肌病特点分析

目的:探讨抗HMGCR/SRP抗体阳性的特发性炎性肌病(IIM)的临床和病理特点。方法:收集HMGCR/SRP抗体阳性的IIM患者5例,对其危险因素、临床表现、实验室检查、肌电图、肌肉MRI、肌肉病理、肌炎自身抗体及药物治疗进行分析。结果:抗HMGCR/SRP抗体阳性的IIM患者临床变异较大,但大多有肌肉无力;血清肌酸激酶均较高;5例患者肌电图均表现为典型的肌源性损害。肌肉MRI主要表现为肌肉水肿。3例为典型坏死性肌病表现,1例镜下偶见肌细胞坏死,1例为多发性肌炎表现。HMGCR抗体阳性患者其中1例为正服用他汀药物,另一患者服用抗精神病药物;SRP抗体阳性患者1例为自身免疫性疾病患者,1例长期服用他汀,另1例病因未明确。激素治疗效果不一,2例加用丙种球蛋白治疗,1例加用免疫抑制剂治疗。结论:抗HMGCR/SRP抗体阳性的IIM临床表现各异,肌电图仅能定位肌肉损害,主要依靠肌肉活检,肌炎自身抗体检查更有助于诊断和具体分型,疗效各型不一。     

Raised CK-MB isoenzyme after exercise in a patient with alcoholic myopathy

The relation between exercise, total serum creatine kinase activity, and serum creatine kinase MB isoenzyme in a patient with alcoholic myopathy was investigated. After a short-term exercise the serum values of creatine kinase MB isoenzyme rose to high levels within hours. This finding is important for obvious differential diagnostic reasons.     

Accumulation of calcium by normal and dystrophin-deficient mouse muscle during contractile activity in vitro.

1. Accumulation of calcium by extensor digitorum longus muscles from dystrophin-deficient mdx and control C57BL/10 mice has been studied in vitro by measurements of total muscle calcium and by following the retention of 45Ca resulting from the incubation of muscles with the isotope for up to 2 h. 2. The rate of influx of calcium, calculated from the retention of 45Ca, was linear over 2 h in muscles at rest with no significant difference between mdx and control muscles. 3. Repetitive tetanic stimuli caused a substantial increase in 45Ca flux into both mdx and control muscles. This elevated rate of influx was maintained by control muscle, but not by mdx muscle after stimulation resulting in a significantly smaller total calcium flux into mdx muscle compared with control muscle by 1 h after stimulation. Similar changes were also seen in the total muscle calcium content of mdx and control muscles. Comparison of these results with those for loss of cytosolic creatine kinase previously reported (McArdle, A., Edwards, R.H.T. & Jackson, M.J. Clin. Sci. 1991; 80, 367-71) [1] indicate that control and dystrophin-deficient muscles release equivalent amounts of intracellular creatine kinase in response to the same accumulation of intracellular calcium. 4. These results therefore do not support the hypotheses that dystrophin deficiency in muscle leads to increased calcium influx during contractile activity, or that dystrophin-deficient muscle shows any inherent increased permeability to cytosolic proteins.     

A simple,rapid test for the differential diagnosis of glycogen storage disease type 3

BACKGROUND: Type 3 glycogen storage disease is an inborn error of metabolism in young infants that often requires extensive workup. However, this disease manifests with few symptoms other than hepatosplenomegaly. At adolescence, this disease may cause myopathy and cardiomyopathy. Since a significant portion of referrals to pediatrics is for evaluation of a hepatosplenomegaly, the differential diagnosis of this disease assumes importance. METHODS: The clinical and biochemical findings in 26 patients with the type 3 glycogen storage disease were investigated. Biochemical parameters included ALT, AST, total CK and CK-MB. RESULTS: Changes in ALT, AST and total CK were observed to varying degrees. However, CK was found to be a diagnostic indicator for type 3 glycogen storage disease and appears to be a pathognomic marker. CONCLUSIONS: Use of CK may reduce the need for extensive diagnostic profiles and aid in the rapid identification and initiation of management for patients presenting with hepatosplenomegaly.     

Increased serum lactate dehydrogenase isoenzyme 1 and "flipped" LD-1/LD-2 ratio in myopathy associated with partial carnitine palmitoyltransferase deficiency

We describe a case of a limb-girdle myopathy presenting with myoglobinuria. A partial deficiency of muscle carnitine palmitoyltransferase (EC 2.3.1.21) may also have been present. All "muscle-type" serum enzymes were markedly increased (to between 30- and 400-fold their respective upper reference limits) and creatine kinase (EC 2.7.3.2) isoenzyme 2 (CK-MB) was increased 130-fold but was still less than 2% of the total creatine kinase activity. The isoenzyme pattern of lactate dehydrogenase (EC 1.1.1.27) in serum was "anodic," with isoenzyme 1 greater than isoenzyme 2--an unusual pattern for myopathies. The possible physiological basis for such a finding is discussed.     

Influence of abdominal surgical trauma upon some energy metabolites in the quadriceps muscle in man

Summary. Thirteen patients with gallbladder disease but otherwise healthy were studied in connection with cholecystectomy. Specimens of the lateral vastus muscle were taken by the percutaneous needle biopsy technique during anaesthesia before surgery, on two occasions during surgery and 30 min after discontinuation of anaesthesia. The muscle samples were analysed for glycogen, lactate, citrate, ATP, phosphoryl creatine, creatine and water content. Citrate and lactate concentrations in muscle increased continuously throughout the study. There were no significant changes in the concentration of glycogen, phosphoryl creatine, and ATP in muscle tissue. The increase in citrate concentration is probably related to an augmented uptake and combustion of free fatty acids and 3-hydroxybutyrate in this situation. The data suggest that during anaesthesia and abdominal surgery an increase in the muscle citrate concentration may contribute to the modulation of carbohydrate utilization in skeletal muscle.     

Muscle pain associated with daptomycin

OBJECTIVE: To report a case of muscle pain without pronounced creatine kinase (CK) elevation in a patient receiving daptomycin. CASE SUMMARY: A 26-year-old African American woman had antibiotic intolerance to vancomycin and quinupristin/dalfopristin. She presented with methicillin-resistant Staphylococcus aureus endocarditis that was treated with intravenous daptomycin 6 mg/kg daily for 14 days. The patient developed muscle aches and pains with only a minor elevation (492 U/L) of CK; both resolved after daptomycin was discontinued. DISCUSSION: Daptomycin is a newly approved lipopeptide antibiotic derived from Streptomyces roseosporus with rapid bactericidal activity. Daptomycin has excellent coverage against gram-positive bacteria. The adverse effect profile has included rare reports of myopathy and elevated CK levels. Daptomycin is a promising agent with many potential applications. Once-daily dosing has diminished the preclinical incidence of myopathy. The current package labeling recommends discontinuation of daptomycin with significant myopathy symptoms in association with a CK elevation >1000 U/L or in patients without muscle pain and a CK >10 times normal. CONCLUSIONS: An objective causality assessment revealed that the myopathy was possibly related to daptomycin. Clinicians should recognize that significant myopathy with daptomycin can occur without pronounced CK elevation.     

甲状旁腺功能减退症继发低钙性肌病的临床分析

目的观察甲状旁腺功能减退症继发低钙性肌病的临床特征。方法对13 例甲状旁腺功能减退症继发低钙性肌病患者的临床表现、实验室检查特点和治疗方法进行回顾。结果13 例患者分别为原发性甲状旁腺功能减退症8 例,继发性3 例,假性2 例。继发低钙性肌病表现为发作性手足搐搦,发作性双手足、前臂、小腿痉挛且疼痛,还可见眼睑痉挛、躯干痉挛、咽喉痉挛。部分患者Trousseau 征和Chvostek 征阳性。血清肌酸激酶、乳酸脱氢酶水平升高。经给予足量碳酸钙和骨化三醇治疗,患者肌肉病症状缓解,肌酶恢复正常。结论原发性、继发性或假性甲状旁腺功能减退症均可引起低钙血症,导致肌肉疾病,补充足量碳酸和骨化三醇有效。     

Biochemical and molecular investigation of two Korean patients with glycogen storage disease type III

Abstract Background: Glycogen storage disease type III (GSD-III) is an inborn error of glycogen metabolism caused by a deficiency of the glycogen debranching enzyme, amylo-1,6-glucosidase,4-alpha-glucanotransferase (AGL). Here, we describe two unrelated Korean patients with GSD-III and review their clinical and laboratory findings. Methods: The patients were 18- and 11-month-old girls. They presented with hepatosplenomegaly, developmental delay and hypotonia. The routine laboratory findings showed an elevated serum aspartate aminotransferase, alanine aminotransferase, creatine kinase and triglyceride levels. The blood lactate and uric acid levels were within normal limits. PCR and direct sequencing were performed to determine genetic findings. Results: Glycogen quantitation was markedly increased and AGL activity was undetectable in both patients. Sequence analysis of the AGL gene showed that both patients were compound heterozygotes for c.853C>T (p.R285X) and c.1735+1G>T in one patient, and c.2894_2896delGGAinsTG and c.4090G>C (p.D1364H) in the other patient. The c.2894_2896delGGAinsTG and c.4090G>C (p.D1364H) mutation was a novel finding. Conclusions: GSD-III should be ruled out when a patient presents with hepatic abnormalities, hypoglycemia, myopathy and hyperlipidemia. This is the first report of confirmation of GSD-III in Korean patients by biochemical and genetic findings. Clin Chem Lab Med 2008;46:1245-9.     

Long-term efficacy after [E1-, polymerase-] adenovirus-mediated transfer of human acid-alpha-glucosidase gene into glycogen storage disease type II knockout mice

Glycogen storage disease type II (GSD-II) is a lethal, autosomal recessive metabolic myopathy caused by a lack of acid-alpha-glucosidase (GAA) activity in the cardiac and skeletal muscles. Absence of adequate intralysosomal GAA activity results in massive amounts of glycogen accumulation in multiple muscle groups, resulting in morbidity and mortality secondary to respiratory embarrassment and/or cardiomyopathy. In a mouse model of GSD-II, we demonstrate that infection of the murine liver with a modified adenovirus (Ad) vector encoding human GAA (hGAA) resulted in long-term persistence of the vector in liver tissues for at least 6 months. Despite both a rapid shutdown of hGAA mRNA expression from the vector, as well as the elicitation of anti-hGAA antibody responses (hGAA is a foreign antigen in this model), the hGAA secreted by the liver was taken up by all muscle groups analyzed and, remarkably, persisted in them for at least 6 months. The persistence of the protein also correlated with long-term correction of pathologic intramuscular glycogen accumulations in all muscle groups tested, but most notably the cardiac tissues, which demonstrated a significantly decreased glycogen content for at least 190 days after a single vector injection. The results suggest that gene therapy strategies may have the potential to significantly improve the clinical course for GSD-II patients.