Mitochondrial Diseases

What are mitochondrial diseases?

Mitochondrial diseases (or disorders) refers to a group of inherited conditions that affect the mitochondria. The mitochondria are the structures in each cell of the body that are responsible for making energy, so people with these conditions could have almost any body system affected, most commonly, the brain, muscles, heart, liver, nerves, eyes, ears, and kidneys.

What causes mitochondrial diseases?

Mitochondrial diseases are caused by mutations in either the mitochondrial DNA or nuclear DNA. These mutations lead to dysfunction of the mitochondria and inadequate production of energy, causing the symptoms of the diseases. These mutations follow either an autosomal dominant, an autosomal recessive, or a X-linked pattern of inheritance, depending on the type of condition and the location of the disease-causing mutation.

What are the symptoms of mitochondrial diseases?

The symptoms of mitochondrial diseases may be present at birth, but can occur at any age. Futhermore, because mitochondrial diseases can affect almost any body system, the signs, symptoms, and the severity of the disorders can vary greatly. With that being said, the most common features include the following:

Poor growth
Loss of muscle coordination
Muscle weakness
Seizures
Autism
Vision and/or hearing problems
Developmental delay and/or learning disabilities
Heart, liver, and/or kidney disease
Gastrointestinal disorders
Diabetes
Increased risk of infection
Dementia

How are mitochondrial diseases diagnosed?

Mitochondrial diseases can be difficult to diagnose, and many affected individuals may never actually receive a specific diagnosis. If people are exhibiting a series of symptoms from multiple, unrelated systems of the body, a diagnosis may be suspected. The following tests can then be conducted to support the diagnosis:

Exercise testing
Magnetic resonance spectroscopy to detect abnormalities in the brain’s chemical makeup
MRI or CT scans of the brain
EEG
Electrocardiography and echocardiography to evaluate the heart
Muscle biopsy

Finally, a diagnosis may be confirmed using molecular genetic testing.

What are the available treatments for mitochondrial diseases?

Since the signs and symptoms vary greatly from case to case of mitochondrial diseases, treatment also varies, though it is aimed at alleviating symptoms and slowing the progression of the disorder. For example, treatment could include administering vitamins and supplements, medications for diabetes and/or seizures, physical therapy and exercises, and surgery.