- Elevated circulating creatine kinase activity (HP:0003236): The activity of creatine kinase in the blood circulation is above the upper limit of normal. Evidence: PCS. Frequency: 12/12. (PMID:36799992)
- Centrally nucleated skeletal muscle fibers (HP:0003687): 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: 7/8. (PMID:36799992)
- Rhabdomyolysis (HP:0003201): Breakdown of muscle fibers that leads to the release of muscle fiber contents (myoglobin) into the bloodstream. Evidence: PCS. Frequency: 1/8. (PMID:36799992)
- Abnormal cardiac ventricular function (HP:0030872): An abnormality of the cardiac ventricular function. Evidence: PCS. Frequency: 0/4. (PMID:36799992)
- Fatty replacement of skeletal muscle (HP:0012548): Muscle fibers degeneration resulting in fatty replacement of skeletal muscle fibers. Evidence: PCS. Frequency: 1/1. (PMID:36799992)
- Increased endomysial connective tissue (HP:0100297): 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: 4/8. (PMID:36799992)
- Autistic behavior (HP:0000729): Persistent deficits in social interaction and communication and interaction as well as a markedly restricted repertoire of activity and interest as well as repetitive patterns of behavior. Evidence: PCS. Frequency: 2/10. (PMID:36799992)
- Myositis (HP:0100614): A general term for inflammation of the muscles without respect to the underlying cause. Evidence: PCS. Frequency: 2/8. (PMID:36799992)
- Specific learning disability (HP:0001328): Impairment of certain skills such as reading or writing, coordination, self-control, or attention that interfere with the ability to learn. The impairment is not related to a global deficiency of intelligence. Evidence: PCS. Frequency: 2/10. (PMID:36799992)
- Type 1 muscle fiber predominance (HP:0003803): An abnormal predominance of type I muscle fibers (in general, this feature can only be observed on muscle biopsy). Evidence: PCS. Frequency: 1/8. (PMID:36799992)
- Abnormal nerve conduction velocity (HP:0040129). Evidence: PCS. Frequency: 0/2. (PMID:36799992)
- Muscle weakness (HP:0001324): Reduced strength of muscles. Evidence: PCS. Frequency: 3/12. (PMID:36799992)
- Attention deficit hyperactivity disorder (HP:0007018): Attention deficit hyperactivity disorder (ADHD) manifests at age 2-3 years or by first grade at the latest. The main symptoms are distractibility, impulsivity, hyperactivity, and often trouble organizing tasks and projects, difficulty going to sleep, and social problems from being aggressive, loud, or impatient. Evidence: PCS. Frequency: 1/10. (PMID:36799992)
- Autosomal dominant inheritance (HP:0000006): 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 heterozygotes. In the context of medical genetics, an autosomal dominant disorder is caused when a single copy of the mutant allele is present. Males and females are affected equally, and can both transmit the disorder with a risk of 50% for each child of inheriting the mutant allele. Evidence: PCS. (PMID:36799992)
- Increased variability in muscle fiber diameter (HP:0003557): An abnormally high degree of muscle fiber size variation. This phenotypic feature can be observed upon muscle biopsy. Evidence: PCS. Frequency: 6/8. (PMID:36799992)
- Myalgia (HP:0003326): Pain in muscle. Evidence: PCS. Frequency: 10/12. (PMID:36799992)
- 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: PCS. Frequency: 9/12. (PMID:36799992)
These phenotypes are associated with the disease myopathy with myalgia, increased serum creatine kinase, and with or without episodic rhabdomyolysis 2 (OMIM:620971).