- Skeletal muscle atrophy (HP:0003202, a Human Phenotype Ontology term): The presence of skeletal muscular atrophy (which is also known as amyotrophy). Evidence: PCS. Frequency: 1/1. (PMID:35915960)
- Juvenile onset (HP:0003621, a Human Phenotype Ontology term): Onset of signs or symptoms of disease between the age of 5 and 15 years. Evidence: PCS. Frequency: 1/7. (PMID:34581780)
- Elevated circulating creatine kinase activity (HP:0003236, a Human Phenotype Ontology term): The activity of creatine kinase in the blood circulation is above the upper limit of normal. Evidence: PCS. Frequency: 1/1. (PMID:35915960)
- Centrally nucleated skeletal muscle fibers (HP:0003687, a Human Phenotype Ontology term): An abnormality in which the nuclei of sarcomeres take on an abnormally central localization (or in which this feature is found in an increased proportion of muscle cells). Evidence: PCS. Frequency: 1/1. Onset: Adult onset (HP:0003581, a Human Phenotype Ontology term). (PMID:35915960)
- Rhabdomyolysis (HP:0003201, a Human Phenotype Ontology term): Breakdown of muscle fibers that leads to the release of muscle fiber contents (myoglobin) into the bloodstream. Evidence: PCS. Frequency: 5/8. (PMID:35915960;PMID:34581780)
- Distal upper limb muscle weakness (HP:0008959, a Human Phenotype Ontology term): Reduced strength of the distal musculature of the arms. Evidence: PCS. Frequency: 1/1. Onset: Adult onset (HP:0003581, a Human Phenotype Ontology term). (PMID:35915960)
- Infantile onset (HP:0003593, a Human Phenotype Ontology term): Onset of signs or symptoms of disease between 28 days to one year of life. Evidence: PCS. Frequency: 1/7. (PMID:34581780)
- Motor delay (HP:0001270, a Human Phenotype Ontology term): A type of Developmental delay characterized by a delay in acquiring motor skills. Evidence: PCS. Frequency: 1/1. (PMID:35915960)
- Increased endomysial connective tissue (HP:0100297, a Human Phenotype Ontology term): An increased volume of the endomysium, which is a connective tissue sheath that surrounds each muscle fiber. Together, bundles of muscle fibers form a fasciculus, surrounded by another layer of connective tissue called the perimysium. Evidence: PCS. Frequency: 1/1. (PMID:35915960)
- Progressive proximal muscle weakness (HP:0009073, a Human Phenotype Ontology term): Lack of strength of the proximal muscles that becomes progressively more severe. Evidence: PCS. Frequency: 1/1. (PMID:35915960)
- Childhood onset (HP:0011463, a Human Phenotype Ontology term): Onset of disease at the age of between 1 and 5 years. Evidence: PCS. Frequency: 6/8. (PMID:35915960;PMID:34581780)
- Exercise-induced myalgia (HP:0003738, a Human Phenotype Ontology term): The occurrence of an unusually high amount of muscle pain following exercise. Evidence: PCS. Frequency: 6/8. (PMID:35915960;PMID:34581780)
- Myoglobinuria (HP:0002913, a Human Phenotype Ontology term): Presence of myoglobin in the urine. Evidence: PCS. Frequency: 0/1. (PMID:35915960)
- Proximal lower limb muscle weakness (HP:0008994, a Human Phenotype Ontology term): A lack of strength of the proximal muscles of the legs. Evidence: PCS. Frequency: 1/1. Onset: Adult onset (HP:0003581, a Human Phenotype Ontology term). (PMID:35915960)
- Autosomal recessive inheritance (HP:0000007, a Human Phenotype Ontology term): A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in individuals with two pathogenic alleles, either homozygotes (two copies of the same mutant allele) or compound heterozygotes (whereby each copy of a gene has a distinct mutant allele). Evidence: PCS. (PMID:34581780)
- Increased circulating lactate dehydrogenase concentration (HP:0025435, a Human Phenotype Ontology term): An elevated level of the enzyme lactate dehydrogenase in the blood circulation. Evidence: PCS. Frequency: 1/1. (PMID:35915960)
- Proximal muscle weakness (HP:0003701, a Human Phenotype Ontology term): A lack of strength of the proximal muscles. Evidence: PCS. Frequency: 5/7. (PMID:34581780)
- Muscle fiber necrosis (HP:0003713, a Human Phenotype Ontology term): Abnormal cell death involving muscle fibers usually associated with break in, or absence of, muscle surface fiber membrane and resulting in irreversible damage to muscle fibers. Evidence: PCS. Frequency: 2/2. (PMID:34581780)
- Elevated circulating hepatic transaminase concentration (HP:0002910, a Human Phenotype Ontology term): Elevations of the levels of SGOT and SGPT in the serum. SGOT (serum glutamic oxaloacetic transaminase) and SGPT (serum glutamic pyruvic transaminase) are transaminases primarily found in the liver and heart and are released into the bloodstream as the result of liver or heart damage. SGOT and SGPT are used clinically mainly as markers of liver damage. Evidence: PCS. Frequency: 1/1. (PMID:35915960)
- Elevated circulating creatinine concentration (HP:0003259, a Human Phenotype Ontology term): An increased amount of creatinine in the blood. Evidence: PCS. Frequency: 7/7. Onset: Adult onset (HP:0003581, a Human Phenotype Ontology term). (PMID:34581780)
- Exercise-induced muscle cramps (HP:0003710, a Human Phenotype Ontology term): Sudden and involuntary contractions of one or more muscles brought on by physical exertion. Evidence: PCS. Frequency: 3/8. (PMID:35915960;PMID:34581780)
- Exercise-induced muscle stiffness (HP:0008967, a Human Phenotype Ontology term): A type of muscle stiffness that occurs following physical exertion. Evidence: PCS. Frequency: 1/7. (PMID:34581780)
- Increased variability in muscle fiber diameter (HP:0003557, a Human Phenotype Ontology term): An abnormally high degree of muscle fiber size variation. This phenotypic feature can be observed upon muscle biopsy. Evidence: PCS. Frequency: 1/1. (PMID:35915960)
- Exercise intolerance (HP:0003546, a Human Phenotype Ontology term): 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: PCS. Frequency: 1/1. (PMID:35915960)
These phenotypes are associated with the disease myopathy with myalgia, increased serum creatine kinase, and with or without episodic rhabdomyolysis 1 (OMIM:620138, an entry in Online Mendelian Inheritance in Man).