RARE DISEASE
Glycogen storage disease due to muscle phosphofructokinase deficiency
Glycogen storage disease due to muscle phosphofructokinase deficiency
Glycogen storage disease due to muscle phosphofructokinase deficiency
Synonyms: GSD due to muscle phosphofructokinase deficiency, GSD type 7, GSD type VII, Glycogen storage disease type 7, Glycogen storage disease type VII, Glycogenosis due to muscle phosphofructokinase deficiency, Glycogenosis type 7, Glycogenosis type VII, Tarui disease
Synonyms: GSD due to muscle phosphofructokinase deficiency, GSD type 7, GSD type VII, Glycogen storage disease type 7, Glycogen storage disease type VII, Glycogenosis due to muscle phosphofructokinase deficiency, Glycogenosis type 7, Glycogenosis type VII, Tarui disease
Synonyms: GSD due to muscle phosphofructokinase deficiency, GSD type 7, GSD type VII, Glycogen storage disease type 7, Glycogen storage disease type VII, Glycogenosis due to muscle phosphofructokinase deficiency, Glycogenosis type 7, Glycogenosis type VII, Tarui disease
Drug discovery
22
papers
On emerging therapies
Overview
Glycogen Storage Disease Type VII (Tarui disease) is a rare autosomal recessive disorder caused by PFKM gene mutations, leading to muscle phosphofructokinase deficiency. This disrupts glycolysis, causing glycogen accumulation, exercise intolerance, muscle cramps, hemolytic anemia, and risk of myoglobinuria-induced renal injury. Diagnosis involves muscle biopsy (showing reduced PFK activity), genetic testing, and elevated creatine kinase/uric acid. Management focuses on avoiding strenuous exercise and carbohydrates; ketogenic diets may improve symptoms by promoting fatty acid metabolism.
Key Clinical Insights
Categories: rare genetic diseases, rare hematological diseases, rare inborn errors of metabolism, rare neurological diseases
Research Papers
22 drug discovery papers about Glycogen storage disease due to muscle phosphofructokinase deficiency. Recent publications:
22 drug discovery papers about Glycogen storage disease due to muscle phosphofructokinase deficiency. Recent publications:
categories:
Small molecules
small molecules
2026-09-24 | Utility of Exogenous Ketones and Modified Atkins Diet in a Child With GSD VII (Tarui Disease).
Glycogen storage disease VII (GSD VII), also known as Tarui disease, is caused by a deficiency of the skeletal muscle enzyme, phosphofructokinase (PFK). Classical GSD VII is characterised by reduced exercise capacity and exercise-induced myopathic symptoms, exacerbated with carbohydrate intake. No recommended medical or dietary therapy currently exists to improve exercise symptomology in GSD VII. An 11-year-old female was recommended four trial dietary therapies for 8 weeks each: (1) usual diet, (2) 150 mg/kg exogenous ketones pre-exercise, (3) modified Atkins diet (MAD), (4) MAD and pre-exercise ketones. Clinical assessments comprised cardiopulmonary exercise test, anthropometry, biochemical tests including creatine kinase (CK), quality of life (QoL), heart rate (HR) monitoring and subjective symptom reports. Exogenous ketones improved exercise capacity demonstrated by reduced HR for equivalent exercise workload, and participation in higher intensity exercise for longer duration. MAD improved QoL physical domain score by 29%, normalised CK and halved the number of symptoms reported per 'physically active day'. Dissatisfaction with MAD resulted in unintentional weight loss, and a 20% reduction in QoL emotional domain score, leading to the patient declining the fourth study phase. This study is the first to demonstrate a beneficial effect of exogenous ketones, and separately, MAD, in a child with GSD VII. Exogenous ketones or MAD could be recommended under medical and dietetic supervision in GSD VII. However, consideration must be given to the potential negative impact of MAD on weight and emotional health. Further interventional studies are warranted in this condition.
2025-09-27 | Two Cases of Pulmonary Hypertension Associated with Glycogen Storage Disease
Abstract Background: Glycogen storage disease (GSD) is a group of diseases characterized by a defect of gene expression of the enzymes in the glycogen synthesis.Pulmonary arterial hypertension (PAH) is a rare complications of GSD, which could lead to right heart failure and even dead. Methods: We now report two patients with GSD and PH.We recorded and analyzed the course of the two cases, the blood test results including blood routine, biochemical function, blood gas analysis, common examinations including electrocardiogram, cardiac ultrasound, lung function, chest CT, and targeted drug treatment. Results: The first patient was 39-year-old women with a history of growth retardation and recurrent hypoglycemia and hyperlipidemia. In the past, she had been receiving regular corn starch supplementary food treatment. She was diagnosed with PH through right heart catheterization, mean pulmonary artery pressure(mPAP) was 61mmHg and she began to receive macitentan combined with sildenafil. Another patient was a 34-year-old woman hospitalized in 2018 because of shortness of breath. Echocardiography showed that PASP was 90 mmHg. Right cardiac catheterization showed that the mPAP was 45 mmHg. She was previously diagnosed with GSDI type by exon transcript sequencing, which suggest the presence of G6PC1 mutation. During follow-up, she was first given bosentan and sildenafil.The targeted therapy was changed to riociguat combined with macitentan in2023. Both patients were followed up routine, and after 6 months / 7 years, their systems were significantly improved. Conclusions: We have found that macitentan-based combined targeted drug therapy can significantly alleviate the symptoms of patients with GSD and PH.
2021-12-03 | Crohn disease-like enterocolitis remission after empagliflozin treatment in a child with glycogen storage disease type Ib: a case report.
Besides major clinical/biochemical features, neutropenia and inflammatory bowel disease (IBD) constitute common complications of Glycogen storage disease type Ib (GSD Ib). However, their management is still challenging. Although previous reports have shown benefit of empagliflozin administration on neutropenia, no follow-up data on bowel (macro/microscopic) morphology are available. We herein present for the first time longitudinal assessment of bowel morphology in a GSD Ib child suffering from Crohn disease-like enterocolitis treated with empagliflozin. A 14-year-old boy with GSD Ib and severe IBD was (off-label) treated with empagliflozin (20 mg/day) after informed oral and written consent was obtained from the patient's parents. No adverse events were noted. Clinical symptoms and stool frequency improved within the first week of treatment. Pediatric Crohn disease activity index (PCDAI) normalised within the first month of treatment. Abdomen magnetic resonance imaging (MRI) performed 3 months after treatment initiation showed dramatic decrease in disease activity and length. Similar findings were reported on histology at 5.5 months. At 7.5 months hemoglobin levels normalised and fecal calprotectin almost normalised. Improved neutrophil count, metabolic control and quality of life were also noted. G-CSF dose was decreased by 33% and the patient was partly weaned from tube feeding. This is the first report presenting extensive gastrointestinal morphology follow-up in a GSD Ib patient receiving empagliflozin. The present case suggests that empagliflozin can be safe and effective in inducing IBD remission in GSD Ib patients and can even postpone surgery. Future studies are required to confirm its effect over time and assess its benefit in various disease stages. The development of an international collaborating networks for systematic data collection is worthy.
2021-02-19 | The potential of a ketogenic diet to minimize effects of the metabolic fault in glycogen storage disease V and VII.
To explore the potential of a low carbohydrate ketogenic diet (LCKD) to counter physical activity intolerance, pain and muscle damage for glycogen storage disease (GSD) V and VII, and highlight the realistic possibility that nutrition could be key. Carbohydrate (CHO) ingestion during physical activity in GSDV and a LCKD for GSDVII is common. For the latter, a long-term study demonstrated improvement in physiological markers while on a LCKD. This included improvement in aerobic power and activity tolerance. In GSDV, preliminary research on a LCKD suggest a diet of 75% fat, 15% protein, 10% CHO, is best for improved function and compliance. Ketones provide immediate fuel for acute physical activity, and have an epigenetic role, improving ketone and lipid use. Evidence from elite athletes found a LCKD can increase fat oxidation and is optimal at 70% VO2max. This suggests the need to also improve conditioning via exercise to maximize the benefit of a LCKD. A high CHO diet in GSDV and VII comes with a restricted physical activity capacity alongside significant pain, muscle damage and risk of renal failure. Mounting evidence suggests a LCKD is efficacious for both disorders providing an immediate fuel source which may negate the need for a 'warm-up' prior to every activity and restore 'normal' function.
2020-02-04 | Beneficial Effects of Ketogenic Diet on Phosphofructokinase Deficiency (Glycogen Storage Disease Type VII)
Background: A deficiency of muscle phosphofructokinase (PFKM) causes a rare metabolic muscle disease, the Tarui disease (Glycogen storage disease type VII, GSD VII) characterized by exercise intolerance with myalgia due to an inability to use glucose as an energy resource. No medical treatment for GSD VII currently exists. The aim of this study was to determine whether a dietary intervention with excessive fat intake would benefit GSD VII. Patient and Methods: A ketogenic diet (KD) intervention implemented as a modified Atkins diet was established for one patient with PFKM deficiency, with a low late lactate response and very high ammonia levels associated with exercise. We recorded the KD intervention for a total of 5 years with clinical and physiotherapeutic evaluations and regular laboratory parameters. Cardiopulmonary exercise testing, including breath gas analysis and venous lactate and ammonia measurements, was performed before KD and at 3, 8 months and 5 years after initiation of KD. Results: During the 5 years on KD, the patient's muscle symptoms had alleviated and exercise tolerance had improved. In exercise testing, venous ammonia had normalized, the lactate profile remained similar, but oxygen uptake and mechanical efficiency had increased and parameters showing ventilation had improved. Conclusions: This study is the first to show a long-term effect of KD in GSD VII with an alleviation of muscle symptoms, beneficial effects on breathing, and improvement in exercise performance and oxygen uptake. Based on these findings, KD can be recommended under medical and nutritional supervision for selected patients with GSD VII, although further research of this rare disease is warranted.
gene therapies
2026-09-15 | A Tarui Disease Phenotype with Compensated Hemolysis and a Homozygous PFKM Variant of Uncertain Significance Mimicking Chronic Myelomonocytic Leukemia.
Background and Clinical Significance: Tarui disease, or glycogen storage disease type VII, is a rare autosomal recessive metabolic myopathy caused by muscle phosphofructokinase deficiency. Its manifestations include exercise intolerance, exertional myalgia, muscle cramps, myoglobinuria, rhabdomyolysis, hyperuricemia, and compensated hemolysis. The hematologic phenotype may obscure the underlying metabolic disorder and raise concern for a clonal myeloid neoplasm. Case Presentation: A 23-year-old man was referred for persistent mild thrombocytopenia following evaluation for jaundice and hepatosplenomegaly. He had undergone cholecystectomy at 18 years of age and reported exercise-induced myalgia, muscle cramps, and episodes of dark urine. Laboratory investigations demonstrated mild monocytosis, reticulocytosis, thrombocytopenia, hyperuricemia, elevated lactate dehydrogenase, and predominantly unconjugated hyperbilirubinemia, with a negative direct antiglobulin test. Selected inherited hemolytic disorders, hemoglobinopathies, and paroxysmal nocturnal hemoglobinuria were excluded. Bone marrow examination showed marked erythroid hyperplasia and mild megakaryocytic dysplasia. Testing for JAK2, CALR, and MPL mutations and an extended myeloid next-generation sequencing panel identified no pathogenic variants, and monocytosis resolved during follow-up. Whole-exome sequencing identified a homozygous PFKM missense variant, NM_001354735.1:c.1087A>T, p.(Ile363Phe), classified as a variant of uncertain significance. The patient subsequently developed severe rhabdomyolysis, with a creatine kinase level of 225,000 U/L and recovered after intensive intravenous hydration without renal impairment. Conclusions: Tarui disease should be considered in young patients with compensated hemolysis, hyperuricemia, exertional muscle symptoms, dark urine, or rhabdomyolysis, even when hematologic abnormalities suggest a myeloid disorder. The highly concordant phenotype and homozygous PFKM variant support a clinically probable diagnosis, although pathogenicity remains unconfirmed. Functional and segregation evidence may strengthen causal interpretation and support future variant reclassification.
2014-09-15 | Large animal models and new therapies for glycogen storage disease
Abstract Glycogen storage diseases (GSD), a unique category of inherited metabolic disorders, were first described early in the twentieth century. Since then, the biochemical and genetic bases of these disorders have been determined, and an increasing number of animal models for GSD have become available. At least seven large mammalian models have been developed for laboratory research on GSDs. These models have facilitated the development of new therapies, including gene therapy, which are undergoing clinical translation. For example, gene therapy prolonged survival and prevented hypoglycemia during fasting for greater than one year in dogs with GSD type Ia, and the need for periodic re‐administration to maintain efficacy was demonstrated in that dog model. The further development of gene therapy could provide curative therapy for patients with GSD and other inherited metabolic disorders.
2008-06-18 | Adenovirus and adeno-associated virus-mediated delivery of human myophosphorylase cDNA and LacZ cDNA to muscle in the ovine model of McArdle's disease: expression and re-expression of glycogen phosphorylase.
At present there is no satisfactory treatment for McArdle's disease, deficiency of myophosphorylase. Injection of modified adenovirus 5 (AdV5) and adeno-associated virus 2 (AAV2) vectors containing myophosphorylase expression cassettes, into semitendinosus muscle of sheep with McArdle's disease, produced expression of functional myophosphorylase and some re-expression of the non-muscle glycogen phosphorylase isoforms (both liver and brain) in regenerating fibres. Expression of both non-muscle isoforms was also seen after control injections of AdV5LacZ vectors. There was up to an order of magnitude greater expression of phosphorylase after myophosphorylase vector injection than after LacZ controls (62% of sections with over 1000 positive muscle fibres, versus 7%). The results presented here suggest that the use of viral vector-mediated phosphorylase gene transfer may be applicable to the treatment of McArdle's disease and that sustained re-expression of the brain and liver isoforms should also be investigated as a possible treatment.
1996-08-01 | Molecular Basis of Canine Muscle Type Phosphofructokinase Deficiency
Muscle type phosphofructokinase (M-PFK) deficiency is a rare inherited glycogen storage disease in humans that causes exertional myopathy and hemolysis. The molecular basis of canine M-PFK deficiency, the only naturally occurring animal homologue, was investigated. Lack of M-PFK enzyme activity was caused by a nonsense mutation in the penultimate exon of the M-PFK gene, leading to rapid degradation of a truncated (40 amino acids) and therefore unstable M-PFK protein. A polymerase chain reaction-based test was devised to identify M-PFK-deficient and carrier animals. This represents one of only a few inborn errors of metabolism where the molecular defect has been identified in a large animal model which can now be used to develop and assess novel therapeutic strategies. Muscle type phosphofructokinase (M-PFK) deficiency is a rare inherited glycogen storage disease in humans that causes exertional myopathy and hemolysis. The molecular basis of canine M-PFK deficiency, the only naturally occurring animal homologue, was investigated. Lack of M-PFK enzyme activity was caused by a nonsense mutation in the penultimate exon of the M-PFK gene, leading to rapid degradation of a truncated (40 amino acids) and therefore unstable M-PFK protein. A polymerase chain reaction-based test was devised to identify M-PFK-deficient and carrier animals. This represents one of only a few inborn errors of metabolism where the molecular defect has been identified in a large animal model which can now be used to develop and assess novel therapeutic strategies.
small molecules
2026-09-24 | Utility of Exogenous Ketones and Modified Atkins Diet in a Child With GSD VII (Tarui Disease).
Glycogen storage disease VII (GSD VII), also known as Tarui disease, is caused by a deficiency of the skeletal muscle enzyme, phosphofructokinase (PFK). Classical GSD VII is characterised by reduced exercise capacity and exercise-induced myopathic symptoms, exacerbated with carbohydrate intake. No recommended medical or dietary therapy currently exists to improve exercise symptomology in GSD VII. An 11-year-old female was recommended four trial dietary therapies for 8 weeks each: (1) usual diet, (2) 150 mg/kg exogenous ketones pre-exercise, (3) modified Atkins diet (MAD), (4) MAD and pre-exercise ketones. Clinical assessments comprised cardiopulmonary exercise test, anthropometry, biochemical tests including creatine kinase (CK), quality of life (QoL), heart rate (HR) monitoring and subjective symptom reports. Exogenous ketones improved exercise capacity demonstrated by reduced HR for equivalent exercise workload, and participation in higher intensity exercise for longer duration. MAD improved QoL physical domain score by 29%, normalised CK and halved the number of symptoms reported per 'physically active day'. Dissatisfaction with MAD resulted in unintentional weight loss, and a 20% reduction in QoL emotional domain score, leading to the patient declining the fourth study phase. This study is the first to demonstrate a beneficial effect of exogenous ketones, and separately, MAD, in a child with GSD VII. Exogenous ketones or MAD could be recommended under medical and dietetic supervision in GSD VII. However, consideration must be given to the potential negative impact of MAD on weight and emotional health. Further interventional studies are warranted in this condition.
2025-09-27 | Two Cases of Pulmonary Hypertension Associated with Glycogen Storage Disease
Abstract Background: Glycogen storage disease (GSD) is a group of diseases characterized by a defect of gene expression of the enzymes in the glycogen synthesis.Pulmonary arterial hypertension (PAH) is a rare complications of GSD, which could lead to right heart failure and even dead. Methods: We now report two patients with GSD and PH.We recorded and analyzed the course of the two cases, the blood test results including blood routine, biochemical function, blood gas analysis, common examinations including electrocardiogram, cardiac ultrasound, lung function, chest CT, and targeted drug treatment. Results: The first patient was 39-year-old women with a history of growth retardation and recurrent hypoglycemia and hyperlipidemia. In the past, she had been receiving regular corn starch supplementary food treatment. She was diagnosed with PH through right heart catheterization, mean pulmonary artery pressure(mPAP) was 61mmHg and she began to receive macitentan combined with sildenafil. Another patient was a 34-year-old woman hospitalized in 2018 because of shortness of breath. Echocardiography showed that PASP was 90 mmHg. Right cardiac catheterization showed that the mPAP was 45 mmHg. She was previously diagnosed with GSDI type by exon transcript sequencing, which suggest the presence of G6PC1 mutation. During follow-up, she was first given bosentan and sildenafil.The targeted therapy was changed to riociguat combined with macitentan in2023. Both patients were followed up routine, and after 6 months / 7 years, their systems were significantly improved. Conclusions: We have found that macitentan-based combined targeted drug therapy can significantly alleviate the symptoms of patients with GSD and PH.
2021-12-03 | Crohn disease-like enterocolitis remission after empagliflozin treatment in a child with glycogen storage disease type Ib: a case report.
Besides major clinical/biochemical features, neutropenia and inflammatory bowel disease (IBD) constitute common complications of Glycogen storage disease type Ib (GSD Ib). However, their management is still challenging. Although previous reports have shown benefit of empagliflozin administration on neutropenia, no follow-up data on bowel (macro/microscopic) morphology are available. We herein present for the first time longitudinal assessment of bowel morphology in a GSD Ib child suffering from Crohn disease-like enterocolitis treated with empagliflozin. A 14-year-old boy with GSD Ib and severe IBD was (off-label) treated with empagliflozin (20 mg/day) after informed oral and written consent was obtained from the patient's parents. No adverse events were noted. Clinical symptoms and stool frequency improved within the first week of treatment. Pediatric Crohn disease activity index (PCDAI) normalised within the first month of treatment. Abdomen magnetic resonance imaging (MRI) performed 3 months after treatment initiation showed dramatic decrease in disease activity and length. Similar findings were reported on histology at 5.5 months. At 7.5 months hemoglobin levels normalised and fecal calprotectin almost normalised. Improved neutrophil count, metabolic control and quality of life were also noted. G-CSF dose was decreased by 33% and the patient was partly weaned from tube feeding. This is the first report presenting extensive gastrointestinal morphology follow-up in a GSD Ib patient receiving empagliflozin. The present case suggests that empagliflozin can be safe and effective in inducing IBD remission in GSD Ib patients and can even postpone surgery. Future studies are required to confirm its effect over time and assess its benefit in various disease stages. The development of an international collaborating networks for systematic data collection is worthy.
2021-02-19 | The potential of a ketogenic diet to minimize effects of the metabolic fault in glycogen storage disease V and VII.
To explore the potential of a low carbohydrate ketogenic diet (LCKD) to counter physical activity intolerance, pain and muscle damage for glycogen storage disease (GSD) V and VII, and highlight the realistic possibility that nutrition could be key. Carbohydrate (CHO) ingestion during physical activity in GSDV and a LCKD for GSDVII is common. For the latter, a long-term study demonstrated improvement in physiological markers while on a LCKD. This included improvement in aerobic power and activity tolerance. In GSDV, preliminary research on a LCKD suggest a diet of 75% fat, 15% protein, 10% CHO, is best for improved function and compliance. Ketones provide immediate fuel for acute physical activity, and have an epigenetic role, improving ketone and lipid use. Evidence from elite athletes found a LCKD can increase fat oxidation and is optimal at 70% VO2max. This suggests the need to also improve conditioning via exercise to maximize the benefit of a LCKD. A high CHO diet in GSDV and VII comes with a restricted physical activity capacity alongside significant pain, muscle damage and risk of renal failure. Mounting evidence suggests a LCKD is efficacious for both disorders providing an immediate fuel source which may negate the need for a 'warm-up' prior to every activity and restore 'normal' function.
2020-02-04 | Beneficial Effects of Ketogenic Diet on Phosphofructokinase Deficiency (Glycogen Storage Disease Type VII)
Background: A deficiency of muscle phosphofructokinase (PFKM) causes a rare metabolic muscle disease, the Tarui disease (Glycogen storage disease type VII, GSD VII) characterized by exercise intolerance with myalgia due to an inability to use glucose as an energy resource. No medical treatment for GSD VII currently exists. The aim of this study was to determine whether a dietary intervention with excessive fat intake would benefit GSD VII. Patient and Methods: A ketogenic diet (KD) intervention implemented as a modified Atkins diet was established for one patient with PFKM deficiency, with a low late lactate response and very high ammonia levels associated with exercise. We recorded the KD intervention for a total of 5 years with clinical and physiotherapeutic evaluations and regular laboratory parameters. Cardiopulmonary exercise testing, including breath gas analysis and venous lactate and ammonia measurements, was performed before KD and at 3, 8 months and 5 years after initiation of KD. Results: During the 5 years on KD, the patient's muscle symptoms had alleviated and exercise tolerance had improved. In exercise testing, venous ammonia had normalized, the lactate profile remained similar, but oxygen uptake and mechanical efficiency had increased and parameters showing ventilation had improved. Conclusions: This study is the first to show a long-term effect of KD in GSD VII with an alleviation of muscle symptoms, beneficial effects on breathing, and improvement in exercise performance and oxygen uptake. Based on these findings, KD can be recommended under medical and nutritional supervision for selected patients with GSD VII, although further research of this rare disease is warranted.
gene therapies
2026-09-15 | A Tarui Disease Phenotype with Compensated Hemolysis and a Homozygous PFKM Variant of Uncertain Significance Mimicking Chronic Myelomonocytic Leukemia.
Background and Clinical Significance: Tarui disease, or glycogen storage disease type VII, is a rare autosomal recessive metabolic myopathy caused by muscle phosphofructokinase deficiency. Its manifestations include exercise intolerance, exertional myalgia, muscle cramps, myoglobinuria, rhabdomyolysis, hyperuricemia, and compensated hemolysis. The hematologic phenotype may obscure the underlying metabolic disorder and raise concern for a clonal myeloid neoplasm. Case Presentation: A 23-year-old man was referred for persistent mild thrombocytopenia following evaluation for jaundice and hepatosplenomegaly. He had undergone cholecystectomy at 18 years of age and reported exercise-induced myalgia, muscle cramps, and episodes of dark urine. Laboratory investigations demonstrated mild monocytosis, reticulocytosis, thrombocytopenia, hyperuricemia, elevated lactate dehydrogenase, and predominantly unconjugated hyperbilirubinemia, with a negative direct antiglobulin test. Selected inherited hemolytic disorders, hemoglobinopathies, and paroxysmal nocturnal hemoglobinuria were excluded. Bone marrow examination showed marked erythroid hyperplasia and mild megakaryocytic dysplasia. Testing for JAK2, CALR, and MPL mutations and an extended myeloid next-generation sequencing panel identified no pathogenic variants, and monocytosis resolved during follow-up. Whole-exome sequencing identified a homozygous PFKM missense variant, NM_001354735.1:c.1087A>T, p.(Ile363Phe), classified as a variant of uncertain significance. The patient subsequently developed severe rhabdomyolysis, with a creatine kinase level of 225,000 U/L and recovered after intensive intravenous hydration without renal impairment. Conclusions: Tarui disease should be considered in young patients with compensated hemolysis, hyperuricemia, exertional muscle symptoms, dark urine, or rhabdomyolysis, even when hematologic abnormalities suggest a myeloid disorder. The highly concordant phenotype and homozygous PFKM variant support a clinically probable diagnosis, although pathogenicity remains unconfirmed. Functional and segregation evidence may strengthen causal interpretation and support future variant reclassification.
2014-09-15 | Large animal models and new therapies for glycogen storage disease
Abstract Glycogen storage diseases (GSD), a unique category of inherited metabolic disorders, were first described early in the twentieth century. Since then, the biochemical and genetic bases of these disorders have been determined, and an increasing number of animal models for GSD have become available. At least seven large mammalian models have been developed for laboratory research on GSDs. These models have facilitated the development of new therapies, including gene therapy, which are undergoing clinical translation. For example, gene therapy prolonged survival and prevented hypoglycemia during fasting for greater than one year in dogs with GSD type Ia, and the need for periodic re‐administration to maintain efficacy was demonstrated in that dog model. The further development of gene therapy could provide curative therapy for patients with GSD and other inherited metabolic disorders.
2008-06-18 | Adenovirus and adeno-associated virus-mediated delivery of human myophosphorylase cDNA and LacZ cDNA to muscle in the ovine model of McArdle's disease: expression and re-expression of glycogen phosphorylase.
At present there is no satisfactory treatment for McArdle's disease, deficiency of myophosphorylase. Injection of modified adenovirus 5 (AdV5) and adeno-associated virus 2 (AAV2) vectors containing myophosphorylase expression cassettes, into semitendinosus muscle of sheep with McArdle's disease, produced expression of functional myophosphorylase and some re-expression of the non-muscle glycogen phosphorylase isoforms (both liver and brain) in regenerating fibres. Expression of both non-muscle isoforms was also seen after control injections of AdV5LacZ vectors. There was up to an order of magnitude greater expression of phosphorylase after myophosphorylase vector injection than after LacZ controls (62% of sections with over 1000 positive muscle fibres, versus 7%). The results presented here suggest that the use of viral vector-mediated phosphorylase gene transfer may be applicable to the treatment of McArdle's disease and that sustained re-expression of the brain and liver isoforms should also be investigated as a possible treatment.
1996-08-01 | Molecular Basis of Canine Muscle Type Phosphofructokinase Deficiency
Muscle type phosphofructokinase (M-PFK) deficiency is a rare inherited glycogen storage disease in humans that causes exertional myopathy and hemolysis. The molecular basis of canine M-PFK deficiency, the only naturally occurring animal homologue, was investigated. Lack of M-PFK enzyme activity was caused by a nonsense mutation in the penultimate exon of the M-PFK gene, leading to rapid degradation of a truncated (40 amino acids) and therefore unstable M-PFK protein. A polymerase chain reaction-based test was devised to identify M-PFK-deficient and carrier animals. This represents one of only a few inborn errors of metabolism where the molecular defect has been identified in a large animal model which can now be used to develop and assess novel therapeutic strategies. Muscle type phosphofructokinase (M-PFK) deficiency is a rare inherited glycogen storage disease in humans that causes exertional myopathy and hemolysis. The molecular basis of canine M-PFK deficiency, the only naturally occurring animal homologue, was investigated. Lack of M-PFK enzyme activity was caused by a nonsense mutation in the penultimate exon of the M-PFK gene, leading to rapid degradation of a truncated (40 amino acids) and therefore unstable M-PFK protein. A polymerase chain reaction-based test was devised to identify M-PFK-deficient and carrier animals. This represents one of only a few inborn errors of metabolism where the molecular defect has been identified in a large animal model which can now be used to develop and assess novel therapeutic strategies.
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