Mitochondrial Myopathy
Mitochondrial Myopathy
(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)
Definition
| Muscular and Nervous Systems |
|
| Mitochondrial myopathies decrease the ability of nerves and muscles. Weakness and uncoordinated movement may result. |
| Copyright © Nucleus Medical Media, Inc. |
Risk Factors
Symptoms
| 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 (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 breathing |
| Mitochondrial DNA depletion syndrome | Infancy | Muscle weakness and liver failure, floppiness, feeding difficulties, and developmental delay |
| Mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS) | Childhood to adulthood | Stroke-like 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 |
- 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
Diagnosis
- 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
Treatment
Dietary Supplements
Physical Therapy
Speech Therapy
Respiratory Therapy
Medications
RESOURCES
Muscular Dystrophy Association http://www.mda.org/
National Institute of Neurological Disorders and Stroke http://www.ninds.nih.gov/
CANADIAN RESOURCES
Canadian Institute of Health Research http://www.cihr-irsc.gc.ca/
Muscle Dystrophy Canada http://www.muscle.ca/
References
Bradley WG, Daroff RB, Fenichel GM, Jankovic J, eds. Neurology in Clinical Practice . 5th ed. Philadelphia, PA: Butterworth Heniemann Elsevier; 2008.
DiMauro S. Pathogenesis and treatment of mitochondrial myopathies: recent advances. Acta Myol. 2010;29(2):333-338.
Facts about mitochondrial myopathies. Muscular Dystrophy Association website. Available at: http://www.mda.org/publications/mitochondrial%5Fmyopathies.html . Accessed December 27, 2012.
Fauci A, Harrison TR. Harrison's Principles of Internal Medicine . 17th ed. New York, NY: McGraw-Hill; 2008.
Jacobs L, Wert GD, Geraedts J, de Coo I, Smeets H. The transmission of OXPHOS disease and methods to prevent this. Hum Reprod Update . 2006;12(2):119-136.
Metabolic myopathies. American College of Rheumatology website. Available at: http://www.rheumatology.org/public/factsheets/diseases%5Fand%5Fconditions/metabolicmyopathies.asp?aud=pat . Accessed December 27, 2012.
Mitochondrial myopathies. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/what.php . Updated November 7, 2012. Accessed December 27, 2012.
Mitochondrial myopathy. National Institute of Neurological Disorders and Stroke website. Available at: http://www.ninds.nih.gov/disorders/mitochondrial%5Fmyopathy/mitochondrial%5Fmyopathy.htm . Accessed December 27, 2012.