What Is Mitochondrial Disease?

A disease that affects multiple organ symptoms

Mitochondria. Wikimedia Commons

Inside body cells are tiny little parts called mitochondria (as many as 1,000 per cell). Mitochondria produce the energy our cells need to grow and function. If the mitochondria are damaged or malfunctioning, the cells cannot carry out their functions, and can become injured or die. These injured or underperforming cells ultimately cause mitochondrial disease.

Mitochondrial disease can be difficult to diagnose because the disease can present with a wide variety of symptoms, ranging from mild to severe.

There are hundreds of different types of mitochondrial diseases. The type you have depends on which cells are affected. Problems may begin at birth or occur later. Most cases are diagnosed during childhood, although adult-onset cases are becoming more common. Mitochondrial disease affects between 40,000 and 70,000 Americans, occurring in one in 2,500 to 4,000 births.

Mitochondrial disease is a genetic condition. The disease can either be inherited from your parents or the result of a random mutation in your DNA. Mitochondria can also be injured from drug use or damage caused by free radicals (destructive molecules). A large number of genetic mutations can cause the disease. However, the same mutation in two different people might not produce the same symptoms.

Signs and Symptoms of Mitochondrial Disease

Because mitochondria are present in 90 percent of our cells, a variety of organs can be affected –– including the brain and muscles.

The most affected systems are typically the brain, heart, liver, skeletal muscles, kidney, and endocrine and respiratory systems. The symptoms you have depends on which cells and organs are affected, these may include:

  • Muscles: weakness, low tone, cramping, pain
  • Heart disease
  • Eyes: twitching, vision loss
  • Kidney disease
  • Respiratory problems
  • Hearing loss

Other symptoms include gastrointestinal disorders, difficulty swallowing, cardiac disease, liver disease, diabetes, lactic acidosis, and an increased likelihood of getting infections. In children, the disease can also cause poor growth and developmental delays. Diagnosing mitochondrial disease is often difficult since symptoms vary and can mimic other conditions. Multiple organ system involvement, three or more areas, is often indicative of mitochondrial disease. 

Treating Mitochondrial Dysfunction

Most cases of mitochondrial disease can be diagnosed through muscle biopsy. Other testing options include blood tests, genetic testing, and enzyme testing. Muscle biopsies and other tests can be very expensive, leaving cases to be diagnosed on clinical presentation alone.

There is no cure for mitochondrial disease. Certain supplements –– thiamine (B1), riboflavin (B12), vitamin C, vitamin E, Lipoic acid, and coenzyme Q10 –– may help treat certain aspects of the disease.

 Avoiding stress may also help reduce symptoms. 

Researchers are currently looking into drugs that would block the lactic acid buildup associated with mitochondrial disease. Others are trying very low carbohydrate diets to reduce the mitochondria’s workload. 

Linking Mitochondrial Dysfunction to Other Diseases

Researchers are studying mitochondrial disease for clues to other conditions such as cancer, Parkinson’s disease, Alzheimer’s diseases, and heart disease. Damage to the mitochondria is thought to be associated with all of those conditions. A lifetime of mitochondrial damage may be part of the aging process.

Information for this article was taken from:
- Foreman, J. Diseases can affect the power in our cells. The Boston Globe, June 17, 2003.
- United Mitochondrial Disease Foundation.

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