- Elevated circulating creatine kinase activity (HP:0003236): The activity of creatine kinase in the blood circulation is above the upper limit of normal. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:368)
- Exercise intolerance (HP:0003546): A functional motor deficit where individuals whose responses to the challenges of exercise fail to achieve levels considered normal for their age and gender. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:368)
- Increased muscle glycogen content (HP:0009051): An increased amount of glycogen in muscle tissue. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:368)
- Glycogen accumulation in muscle fiber lysosomes (HP:0030231): An increased amount of glycogen in muscle tissue found specifically in lysosomes. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:368)
- Highly elevated creatine kinase (HP:0030234): An increased CPK level between 4X and 50X above the upper normal level. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:368)
- Rhabdomyolysis (HP:0003201): Breakdown of muscle fibers that leads to the release of muscle fiber contents (myoglobin) into the bloodstream. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:368)
- Recurrent myoglobinuria (HP:0003652): Recurring episodes of myoglobinuria, i.e., of the presence of myoglobin in the urine. This is usually a consequence of rhabdomyolysis, i.e., of the destruction of muscle tissue. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:368)
- Exercise-induced muscle cramps (HP:0003710): Sudden and involuntary contractions of one or more muscles brought on by physical exertion. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:368)
- Exercise-induced myoglobinuria (HP:0008305): Presence of myoglobin in the urine following exercise. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:368)
- Dark urine (HP:0040319): An abnormal dark color of the urine. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:368)
- Muscle weakness (HP:0001324): Reduced strength of muscles. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:368)
- Hypertrophic cardiomyopathy (HP:0001639): Hypertrophic cardiomyopathy (HCM) is defined by the presence of increased ventricular wall thickness or mass in the absence of loading conditions (hypertension, valve disease) sufficient to cause the observed abnormality. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:368)
- Tachycardia (HP:0001649): A rapid heartrate that exceeds the range of the normal resting heartrate for age. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:368)
- Acute kidney injury (HP:0001919): Sudden loss of renal function, as manifested by decreased urine production, and a rise in serum creatinine or blood urea nitrogen concentration (azotemia). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:368)
- Exertional dyspnea (HP:0002875): Perceived difficulty to breathe that occurs with exercise or exertion and improves with rest. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:368)
- Skeletal muscle atrophy (HP:0003202): The presence of skeletal muscular atrophy (which is also known as amyotrophy). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:368)
- Exercise-induced myalgia (HP:0003738): The occurrence of an unusually high amount of muscle pain following exercise. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:368)
- Exercise-induced muscle stiffness (HP:0008967): A type of muscle stiffness that occurs following physical exertion. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:368)
- Progressive proximal muscle weakness (HP:0009073): Lack of strength of the proximal muscles that becomes progressively more severe. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:368)
- Fatigue (HP:0012378): A subjective feeling of tiredness characterized by a lack of energy and motivation. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:368)
- Postexertional symptom exacerbation (HP:0030973): Post-exertional symptom exacerbation (PESE), also referred to as post-exertional malaise (PEM), is defined as the worsening of symptoms that can follow minimal cognitive, physical, emotional, or social activity, or activity that could previously be tolerated. Symptoms typically worsen 12 to 72 hours after activity and can last for days or even weeks, sometimes leading to a relapse. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:368)
- Dysphagia (HP:0002015): Difficulty in swallowing. Evidence: TAS. Frequency: Very rare (HP:0040284). (ORPHA:368)
- Impaired mastication (HP:0005216): An abnormal reduction in the ability to masticate (chew), i.e., in the ability to crush and ground food in preparation for swallowing. Evidence: TAS. Frequency: Very rare (HP:0040284). (ORPHA:368)
- Chronic kidney disease (HP:0012622): Functional anomaly of the kidney persisting for at least three months. Evidence: TAS. Frequency: Very rare (HP:0040284). (ORPHA:368)
These phenotypes are associated with the disease Glycogen storage disease due to muscle glycogen phosphorylase deficiency (ORPHA:368).