Mitochondrial Myopathy
En Español (Spanish Version)Mitochondrial myopathies are a group of diseases. Each disease has different symptoms. Some may be mild while other are life-threatening. However, the diseases are all caused by a problem with the mitochondria.
Mitochondria are tiny structures found in almost all cells. It is their job to provide energy to these cells. Mitochondrial myopathies can interfere with many different bodily functions. It tends to have the greatest impact on structures that are very active such as the muscles and nerves.
Muscular and Nervous Systems
Mitochondrial myopathies decrease the ability of nerves and muscles. Weakness and uncoordinated movement may result.
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This condition is caused by a mutation in a specific gene.
Having a family member with the mutated gene increases the risk of mitochondrial myopathies.
Mitochondrial myopathies can cause a range of symptoms. Symptoms by specific condition include:
NAME OF CONDITIONAGE OF ONSETDEFINING SYMPTOMSKearns-Sayre syndrome (KSS)Before age 20Salt and pepper pigmentation in eye, eye movement problems (PEO), heart and skeletal muscle dysfunctionLeigh’s syndromeInfancy (can appear later)Brain abnormalities that lead to muscle problems, seizures, uncoordinated muscle movement (ataxia), impaired vision and hearing, developmental delay and poor control over breathingMitochondrial DNA depletion syndromeInfancyMuscle weakness and liver failure, floppiness, feeding difficulties, and developmental delayMitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS)Childhood to adulthoodStroke-like episodes, migraine headaches, vomiting and seizures, muscle weakness, exercise intolerance, hearing loss, diabetes, short statureMyoclonic epilepsy associated with ragged red fibers (MERRF)Late childhood to adulthoodMyoclonus (jerky movements), seizures, muscle weakness, uncoordinated muscle movement (ataxia)Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE)Before age 20Eye movement problems (PEO), drooping eyelid, limb weakness, digestive problems, peripheral neuropathyNeuropathy, ataxia, and retinitis pigmentosa (NARP)Early childhood to adulthoodUncoordinated muscle movement (ataxia), degeneration of the retina in the eye leading to loss of visionPearson’s syndromeInfancyCauses severe anemia and pancreas problems, survivors usually develop KSSProgressive external ophthalmoplegia (PEO)AdulthoodEye movement difficulty, and often symptoms of other mitochondrial diseases, but can be an independent syndrome
Other general symptoms include:
- Muscle weakness or exercise intolerance
- Lack of balance or coordination
- Arryhthmias of the heart or heart failure
- Problems with eye movements—either problems with control or inability to move them
- Seizures
- Stroke-like episodes
- Vomiting
- Dementia
Your doctor will ask about your symptoms and medical history. A physical exam will be done. You will also be asked about any family history of the disease.
Tests may include the following:
-
Muscle
biopsy—to look for abnormal levels of mitochondria
- Blood test—to look for abnormal levels of certain enzymes and other substances
- Lumbar puncture (spinal tap)
—to evaluate the fluid surrounding the brain and spinal cord
- Electromyography
(EMG) and nerve conduction velocity (NCV)—to test nerve and muscle interaction
- Genetic test
- Eye exam
There is no specific treatment for these diseases. Instead, treatment will focus on managing the symptoms. Treatment options include the following:
Supplements may help make energy in the cells. These may include:
Work with your doctor on the doses of these supplements.
Therapy may be used to strengthen muscles and improve mobility. Some may need devices like braces,
walkers
, or
wheelchairs to help them get around.
Muscle weakness in the throat may make talking or swallowing difficult. Speech therapy may help strengthen the muscles or work around the weakness.
Respiratory therapy will help make sure you are breathing properly. It may involve some training techniques for respiratory muscles. It can include pressurized air treatment or the use of a ventilator.
Medicines may be needed for symptoms such as seizures or pain.
There are no known guidelines to prevent this condition.
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Last Reviewed December 2012