The mechanism by which<unk>  occur is not yet well understood. The human mitochondrial tRNA mutations are associated with a variety of diseases including mitochondrial myopathies. However, it is understood that defects in the mitochondrial DNA (mtDNA) have been associated with these diseases, and studies have been able to assign biochemical defects. One of these defects has to do with the decreased energy available for cell processes. As muscles are stained with Gömöri trichrome, characteristic ragged red fibers are visible under the microscope. This appearance is due to the accumulation of abnormal mitochondria below the plasma membrane of the muscle fiber. These may extend throughout the muscle fiber as the disease severity increases. The mitochondrial aggregates cause the contour of the muscle fiber to become irregular, leading to the "ragged" appearance.
MERRF syndrome
Hagemoser–Weinstein–Bresnick syndrome
VEXAS syndrome
Hughes–Stovin syndrome
Smith–Fineman–Myers syndrome
Crome syndrome
RIDDLE syndrome
3-M syndrome