Myoclonic epilepsy with ragged red fibers (MERRF) is a rare disease that mostly affects the nervous system and the muscles. The nervous system includes the brain, spinal cord, and nerves throughout the body which controls all movement, sensation, and brain activity of the body. The condition most often appears early in childhood.
Symptoms of MERRF may include “ragged red fibers” in the muscle which can indicate dead muscle tissue, myoclonic episodes (involuntary muscle jerks/spasms), epileptic seizures, difficulty controlling bodily movements, weakness, and dementia. Other possible symptoms may include a loss of sensation in extremities, a decline in intellectual function, heart problems, and hearing/vision loss.
Mutations in the MT-TK gene is the most common cause of MERRF. Genes are made up of DNA that create proteins responsible for normal body processes, and are passed down from parent to child. When a gene is mutated, the proteins don’t function properly and normal processes are disrupted. The MT-TK gene is exclusively passed down through the mother, though just because a mother has the condition, it is not guaranteed that her child will have it as well.
MERRF is usually diagnosed through an examination of symptoms and family health history. Additionally, a biopsy (the taking of a sample physically) of the muscle tissue to check for ragged red fibers may be taken to help lead to the diagnosis. Genetic testing may also be available to confirm the mutated mitochondrial gene(s) like MT-TK.
There is currently no cure for MERRF, but its symptoms can be managed. Anti-seizure and other medications may be prescribed to treat seizures and myoclonus, and physical therapy or aerobic exercise may help improve muscle weakness or stiffness.
If you or a family member have been diagnosed with MERRF speak with your doctor to learn more information. Support groups may also be available for further resources.
Description Last Updated: Aug 24, 2018