What is IamGSD?

We are a patient-led international group encouraging efforts by research and medical professionals, national support groups and individual patients worldwide.

What is Muscle GSD?

Human bodies make glucose from carbohydrates. Excess glucose is stored as glycogen in our muscles and liver. Muscle glycogen storage disease is when our muscles cannot convert their glycogen back into glucose to power our muscles.

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If you have another muscle GSD please contact us.

Site updated: March 2020.

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CURRENT RESEARCH

Seeking to join a trial?

You can search the Clinical Trials registry for research that has reached the stage of a clinical trial. Use search terms to focus the results on current studies of relevance to you. 

The following studies and trials relevant to Muscle GSD are currently in progress and expected to report soon. 

A ROWING ERGOMETRY TEST FOR ASSESSMENT OF VO2 PEAK IN MCARDLE DISEASE

Brunel University, London

All of the current physical activity protocols for exercising McArdle’s patients are completed on exercise machines that only utilise the lower body (Treadmills, Cycle ergometers). Whole body machines (Rowing ergometers) have never been used before for McArdle’s patients for whole body exercise prescription as it can be more challenging than lower. Whole body exercise will provide more beneficial health outcomes as the upper body doesn’t normally get conditioned at all, therefore, being able to condition the upper body in conjunction with the lower is an ideal start to begin more upper body training in McArdle’s patients. Therefore the appropriate creation of a whole body rowing protocol is needed for delivering rowing ergometry tests in McArdle’s patients. 

MODIFIED KETOGENIC DIET IN PATIENTS WITH MCARDLE DISEASE (PART B)

Copenhagen and London

A placebo-controlled, blind, cross over study to be carried out at two sites: CNMC (Copenhagen), NHNN (London). Subjects will first receive either a modified ketogenic diet (75% fat, 15%protein, 10% carbohydrates) or a placebo diet (>100grams of carbohydrates per day). They will follow the diet for 4 weeks, followed by 2-4 weeks wash-out, followed by 4 weeks on the opposite diet. They will visit the trial site in London five times. Evaluation will be on exercise capacity during submaximal exercise test on a cycle ergometer, and by questionnaires and a dietary diary.

REN001: TO EVALUATE THE SAFETY AND TOLERABILITY OF TREATMENT IN PATIENTS WITH MCARDLE DISEASE

London and Madrid

REN001 is a new drug currently under development that has been given to 53 healthy volunteers and 30 obese patients with high lipid levels in controlled clinical trials. REN001 was considered safe and well tolerated. Laboratory and clinical trial data indicated that REN001 improves energy production by mitochondria within muscle cells and may improve muscle function. This is a Phase 1B, 12 week, open-label study to determine whether oral treatment with REN001 is safe and well tolerated in patients with McArdle disease.

INVESTIGATION OF THE EXISTENCE AND CHARACTERISTICS OF A “THIRD WIND” PHENOMENON IN MCARDLE DISEASE

Brunel University, London

Individuals with McArdle disease have an impaired carbohydrate metabolism which limits their physical activity capacity, especially at the beginning of activity and during anaerobic exercise.  Second wind is a well established phenomenon in this muscle myopathy and is characterized by a sudden decrease in heart rate and improvement in activity tolerance at approximately 8-10 min of low intensity exercise.  Some patients have reported that prolonged exercise of more than 2 hours results in another improvement in activity tolerance, which anecdotally has been coined ‘third wind’.  This study aimed to explore this phenomenon by exercising McArdle patients on a treadmill for 2.5 continuous hours and compare the findings with a pathology-free control group.

A PHASE II PILOT STUDY TO EXPLORE TREATMENT WITH SODIUM VALPROATE IN ADULTS WITH MCARDLE DISEASE

London and Copenhagen

McArdle disease is a metabolic myopathy characterized by the absence of glycogen phosphorylase in skeletal muscle. Sodium Valproate is part of a group of drugs known as histone deacetylase inhibitors, which have a direct effect on chromatin. Recently a drug trial in an animal model of McArdle disease showed that sodium valproate stimulated the expression of a different isoform of the missing enzyme in skeletal muscle.

THE EFFECT OF TRIHEPTANOIN IN ADULTS WITH MCARDLE DISEASE

Copenhagen and Paris

In other metabolic diseases studies of Triheptanoin diet have shown that Triheptanoin increased metabolism of both fat and sugar, and had a positive effect on physical performance and reduced the level of symptoms. However, in McArdle’s the interpretation of the findings was negative: “Despite increased resting plasma malate with Triheptanoin, the increase was insufficient to generate a normal TCA turnover during exercise and the treatment has no effect on exercise capacity or oxidative metabolism in patients with McArdle disease.”

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