An abnormal appearance of muscle fibers observed on muscle biopsy. Ragged red fibers can be visualized with Gomori trichrome staining as irregular and intensely red subsarcolemmal zones, whereas the normal myofibrils are green. The margins of affect fibers appear red and ragged. The ragged-red is due to the accumulation of abnormal mitochondria below the plasma membrane of the muscle fiber, leading to the appearance of a red rim and speckled sarcoplasm. (Human Phenotype Ontology, HP_0003200)
12 genes associated with the ragged-red muscle fibers phenotype by mapping known disease genes to disease phenotypes from the HPO Gene-Disease Associations dataset.
