Mitochondrial Disease

What is Mitochondrial Myopathies?

Mitochondrial myopathies are a group of neuromuscular diseases caused by damage to the mitochondria-small, energy-producing structures that serve as the cells' "power plants." Nerve cells in the brain and muscles require a great deal of energy, and thus appear to be particularly damaged when mitochondrial dysfunction occurs. Some of the more common mitochondrial myopathies include Kearns-Sayre syndrome, myoclonus epilepsy with ragged-red fibers, and mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes. The symptoms of mitochondrial myopathies include:

• muscle weakness or exercise intolerance,
  
• heart failure or rhythm disturbances,
  
• dementia,
  
• movement disorders,
  
• stroke-like episodes,
  
• deafness,
  
• blindness,
  
• droopy eyelids,
  
• limited mobility of the eyes,
  
• vomiting, and
  
• seizures.

The prognosis for these disorders ranges in severity from progressive weakness to death. Most mitochondrial myopathies occur before the age of 20, and often begin with exercise intolerance or muscle weakness. During physical activity, muscles may become easily fatigued or weak. Muscle cramping is rare, but may occur. Nausea, headache, and breathlessness are also associated with these disorders.

Is there any treatment for mitochondrial disease?

Although there is no specific treatment for any of the mitochondrial myopathies, physical therapy may extend the range of movement of muscles and improve dexterity. Vitamin therapies such as riboflavin, coenzyme Q, and carnitine (a specialized amino acid) may provide subjective improvement in fatigue and energy levels in some patients.

What is the prognosis for mitochondrial disease?

The prognosis for patients with mitochondrial myopathies varies greatly, depending largely on the type of disease and the degree of involvement of various organs. These disorders cause progressive weakness and can lead to death.

What research is being done for mitochondrial disease?

The NINDS conducts and supports research on mitochondrial myopathies. The goals of this research are to increase scientific understanding of these disorders and to find ways to effectively treat, prevent, or potentially cure them.
Select this link to view a list of studies currently seeking patients.

Organizations

Muscular Dystrophy Association
3300 East Sunrise Drive
Tucson, AZ 85718-3208
mda@mdausa.org
http://www.mda.org
Tel: 520-529-2000
800-344-4863
Fax: 520-529-5300
United Mitochondrial Disease Foundation
8085 Saltsburg Road Suite 201
Pittsburgh, PA 15239
info@umdf.org
http://www.umdf.org
Tel: 412-793-8077
Fax: 412-793-6477
National Organization for Rare Disorders (NORD)
P.O. Box 1968 (55 Kenosia Avenue)
Danbury, CT 06813-1968
orphan@rarediseases.org
http://www.rarediseases.org
Tel: 203-744-0100
Voice Mail 800-999-NORD (6673)
Fax: 203-798-2291

SOURCES: 
National Institute of Neurological Disorders and Stroke

Medicinenet.com.