(Kearns-Sayre Syndrome; Leigh’s Syndrome; Mitochondrial DNA Depletion Syndrome; Mitochondrial Encephalomyopathy, Lactic Acidosis and Strokelike Episodes; Myoclonic Epilepsy Associated With Ragged Red Fibers; Mitochondrial Neurogastrointestinal Encephalopathy; Neuropathy, Ataxia, and Retinitis Pigmentosa; Pearson’s Syndrome; Progressive External Ophthalmoplegia)
Pronounced: My–toe-con-dree-al My-op-a-thee
Mitochondria are tiny structures in all cells. They provide energy. Mitochondrial myopathies are a group of diseases that affect them. The diseases affect the nerves and muscles, among other systems. The severity of these diseases can vary greatly. Some produce mild symptoms and others have life-threatening conditions. Mitochondrial myopathies include:
|NAME OF CONDITION||AGE OF ONSET||DEFINING SYMPTOMS|
|Kearns-Sayre Syndrome (KSS)||Before age 20||Salt and pepper pigmentation in eye, eye movement problems (PEO), heart and skeletal muscle dysfunction|
|Leigh’s Syndrome||Infancy||Brain abnormalities that lead to muscle problems, seizures, uncoordinated muscle movement (ataxia), impaired vision and hearing, developmental delay and poor control over breathing|
|Mitochondrial DNA Depletion Syndrome||Infancy||Muscle weakness and liver failure, floppiness, feeding difficulties, and developmental delay|
|Mitochondrial Encephalomyopathy, Lactic Acidosis and Strokelike Episodes (MELAS)||Childhood to adulthood||Strokelike episodes, migraine headaches, vomiting and seizures, muscle weakness, exercise intolerance, hearing loss, diabetes, short stature|
|Myoclonic Epilepsy associated with Ragged Red Fibers (MERRF)||Late childhood to adulthood||Myoclonus (jerky movements), seizures, muscle weakness, uncoordinated muscle movement (ataxia)|
|Mitochondrial Neurogastrointestinal Encephalomyopathy (MNGIE)||Before age 20||Eye movement problems (PEO), drooping eyelid, limb weakness, digestive problems, peripheral neuropathy|
|Neuropathy, Ataxia and Retinitis Pigmentosa (NARP)||Early childhood to adulthood||Uncoordinated muscle movement (ataxia), degeneration of the retina in the eye leading to loss of vision|
|Pearson’s Syndrome||Infancy||Causes severe anemia and pancreas problems, survivors usually develop KSS|
|Progressive External Ophthalmoplegia (PEO)||Adulthood||Eye movement difficulty, and often symptoms of other mitochondrial diseases, but can be an independent syndrome|
If you suspect you have this condition, contact your doctor.
Muscular and Nervous Systems
Mitochondrial myopathies can cause a range of symptoms. Some people experience very few symptoms. Others may experience the full range. If you have any of these symptoms, do not assume it is due to this condition, as these symptoms may be caused by a number of conditions.
Tell your doctor if you have any of these:
- Muscle weakness
- Exercise intolerance
- Loss of hearing
- Lack of balance or coordination
- Progressive weakness
- Inability to move eyes
- Heart failure
- Learning deficits
- Strokelike episodes
- Droopy eyelids
- Muscle wasting
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—test that involves removing a small piece of muscle to look for abnormal levels of mitochondria or the presence of certain proteins and enzymes
- Blood test—a blood test that looks for abnormal levels of certain enzymes and other substances
- Genetic test—a blood test or muscle biopsy that tests for the presence of genetic mutations
Talk with your doctor about the best plan for you. There is no specific treatment for these diseases. Symptoms can be treated. Treatment options include the following:
Supplements may help make energy in the cells. These may include:
Therapy may be used to strengthen muscles and improve mobility. Some people may need devices like braces, walkers , or wheelchairs .
Muscle weakness in the throat may require speech therapy.
In some cases, this therapy may be needed. It can include pressurized air treatment or the use of a ventilator.
Medications are used to treat specific symptoms such as:
Muscular Dystrophy Association
National Institute of Neurological Disorders and Stroke
Canadian Institute of Health Research
Muscle Dystrophy Canada
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Mitochondrial myopathies. EBSCO DynaMed website. Available at: http://dynaweb.ebscohost.com/Detail.aspx?id=114475&sid=c9bf3416-a446-427b-a659-4e18bd83b1bc@SRCSM1 . Updated July 2008. Accessed November 17, 2008.
Mitochondrial myopathy. National Institute of Neurological Disorders and Stroke website. Available at: http://www.ninds.nih.gov/disorders/mitochondrial_myopathy/mitochondrial_myopathy.htm . Accessed November 5, 2008.
Thorburn DR, Rahman S. Mitochondrial DNA-Associated Leigh Syndrome and NARP. Genereviews website. Available at: http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=narp . Published October 30, 2003. Updated February 3, 2006. Accessed November 17, 2008.
Last reviewed November 2008 by ]]>Judy Chang, MD, FAASM]]>
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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