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What is Mitochondrial Disease?

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Mitochondrial disease is an inherited chronic illness that can be present at birth or develop later in life. It causes debilitating physical, developmental, and cognitive disabilities with symptoms including poor growth; loss of muscle coordination; muscle weakness and pain; seizures; vision and/or hearing loss; gastrointestinal issues; learning disabilities; and organ failure. It is estimated that 1 in 4,000 people has Mito. It’s progressive and there is no cure.

In 1962, the first patient was diagnosed with a mitochondrial disorder. In 1963, researchers discovered that mitochondria have their own DNA or “blueprint” (mtDNA), which is different than the nuclear DNA (nDNA) found in the cells’ nucleus.

The types of mitochondrial diseases are categorized according to the organ systems affected and symptoms present. Mitochondrial diseases might affect the cells of the brain, nerves (including the nerves to the stomach and intestines), muscles, kidneys, heart, liver, eyes, ears, or pancreas. In some patients, only one organ is affected, while in other patients all the organs are involved. Depending on how severe the mitochondrial disorder is, the illness can range in severity from mild to fatal.

Depending on which cells of the body are affected, symptoms might include:

  • Poor growth
  • Loss of muscle coordination, muscle weakness
  • Visual and/or hearing problems
  • Developmental delays, learning disabilities
  • Mental retardation
  • Heart, liver, or kidney disease
  • Gastrointestinal disorders, severe constipation
  • Respiratory disorders
  • Diabetes
  • Increased risk of infection
  • Neurological problems, seizures
  • Thyroid dysfunction
  • Dementia (mental disorder characterized by confusion, disorientation, and memory loss)

For many patients, mitochondrial disease is an inherited condition that runs in families (genetic). An uncertain percentage of patients acquire symptoms due to other factors, including mitochondrial toxins.

It is important to determine which type of mitochondrial disease inheritance is present, in order to predict the risk of recurrence for future children.

What is the prognosis or outlook?

Once a patient is diagnosed with a specific mitochondrial disease, the patient’s medical problems have already been identified or can be identified with proper testing so treatment can be initiated to relieve symptoms and delay the progression of the disease.

There is no way to predict the course of mitochondrial diseases. They might progress quickly or slowly, even over decades. The disease might also appear stable for years.

For parents considering having other children, genetic counseling is available. Although complex, prenatal testing is only available for a few types of mitochondrial disorders. Please discuss your concerns with your doctor.