Kisho is an information platform, not a medical provider. Nothing on this site constitutes medical advice, diagnosis, or treatment recommendations. All content is aggregated from publicly available sources (including ClinicalTrials.gov, PubMed, FDA.gov, and Orphanet) and is provided for informational purposes only. Clinical trial eligibility, treatment decisions, and any health-related actions should always be discussed with a qualified healthcare professional. Kisho does not endorse any specific therapy, organization, or clinical trial. Terms of use · Privacy policy
Any mitochondrial myopathy and sideroblastic anemia in which the cause of the disease is a mutation in the YARS2 gene.
Features include always present findings: Sideroblastic anemia, Cytochrome C oxidase-negative muscle fibers, Lactic acidosis, and Ragged-red muscle fibers and others; and common findings: Lethargy, Pallor, Low muscle tone (hypotonia), and Motor delay and others. 26 total HPO annotations.
Organ System | Phenotype Count | Example Features |
|---|---|---|
Muscles | 5 | Low muscle tone (hypotonia), Muscle weakness, Cytochrome C oxidase-negative muscle fibers |
Lab test results | 5 | Elevated circulating hepatic transaminase concentration, Decreased activity of mitochondrial complex III, Increased circulating lactate concentration |
Eyes | 3 | Strabismus, Nystagmus, Ptosis |
Digestive system | 3 | Enlarged liver (hepatomegaly), Elevated circulating hepatic transaminase concentration, Difficulty swallowing (dysphagia) |
Growth and development | 2 | Failure to thrive, Growth delay |
Brain and nerves | 2 | Exercise intolerance, Difficulty swallowing (dysphagia) |
Lungs and breathing | 2 | Respiratory distress, Difficulty breathing due to muscle weakness (respiratory insufficiency due to muscle weakness) |
Blood and immune system | 1 | Sideroblastic anemia |
Heart and blood vessels | 1 | Thickened heart muscle (hypertrophic cardiomyopathy) |
YARS2 function has not been fully characterized.
Myopathy, lactic acidosis, and sideroblastic anemia 2 is associated with mutations in the YARS2 gene on chromosome 12.
Genetic testing for YARS2 is available. Testing is considered confirmatory for diagnosis.
Phenotype severity distribution: 8 always present features, 10 common features.
No clinical trials have been registered for myopathy, lactic acidosis, and sideroblastic anemia 2.
2 publications have been identified in PubMed for myopathy, lactic acidosis, and sideroblastic anemia 2. Research spans Review / Meta-Analysis (50%) and Case Report / Case Series (50%).
Villafan-Bernal JR (2026). [PMID: 41614925](https://pubmed.ncbi.nlm.nih.gov/41614925/). *Current issues in molecular biology*. [Review / Meta-Analysis]
Ammar M (2025). [PMID: 39961824](https://pubmed.ncbi.nlm.nih.gov/39961824/). *Annals of hematology*. [Case Report / Case Series]
Data assembled from 5 of 12 sources · Last updated Sep 20, 2026, 5:33 PM UTC
Online Mendelian Inheritance in Man
Genetic and Rare Diseases Info Center