Mitochondrial Diseases

Symptoms of mitochondrial diseases vary based on the type and location of the affected cells. They can range from mild to severe and could include:

• Poor growth.
• Muscle weakness, muscle pain or a low muscle tone.
• Vision and/or hearing loss.
• Developmental delays or issues with cognitive development.
• Diarrhea or constipation.
• Unexplained vomiting.
• Acid reflux and/or swallowing difficulties.
• Seizures.
• Migraines.
• Respiratory (breathing) problems.
• Fainting.

Symptoms of mitochondrial diseases can be present at birth, but they can also arise at any age. A healthcare provider usually detects symptoms affecting more than one organ or organ system at the same time. Symptoms of the same disease can vary from person to person, even among family members.

A lack of energy production from mitochondria in your cells causes mitochondrial disease. Mitochondria are responsible for producing energy within your body. When your mitochondria don’t receive the instructions they need from your body’s DNA to make energy, it can damage your cells or cause them to die early. This affects how your organs and organ systems function, which leads to symptoms of the condition.

How does someone get a mitochondrial disease?

Mitochondrial diseases are genetic. You can inherit these conditions from your biological family in an autosomal dominant or autosomal recessive pattern. This means that you can get a changed (mutated) gene that causes this condition from one or both of your biological parents respectfully. Some cases can occur randomly (de novo) without any history of the condition in your biological family.

Certain cases of mitochondrial disease have a mitochondrial inheritance. This occurs when the mitochondria contain their own DNA. Mitochondrial conditions caused by mutations in the mitochondrial DNA are exclusively inherited from the child’s mother.

Can other conditions cause mitochondrial diseases?

Yes. Mitochondrial dysfunction occurs when mitochondria don’t work as well as they should due to another disease or condition. Many conditions can lead to secondary mitochondrial dysfunction, including:

• Alzheimer’s disease.
• Muscular dystrophy.
• Type 1 diabetes.
• Multiple sclerosis (MS).
• Cancer.

If you have secondary mitochondrial dysfunction, you don’t have a genetic mitochondrial disease.

You’re more at risk of developing a mitochondrial disease if it runs in your biological family history or if you have a condition that causes secondary mitochondrial dysfunction. Mitochondrial disease affects both adults and children.

Mitochondrial diseases affect how your organs function. It can cause the following complications:

• Increased risk of infection.
• Strokes.
• Pancreatic failure.
• Parathyroid failure.
• Diabetes.
• Liver failure.
• Cardiomyopathy.
• Kidney disease.
• Dementia.
• Gastrointestinal conditions.
• Drooping eyelid (ptosis).

Complications can be life-threatening.

A healthcare provider will diagnose a mitochondrial disease after a series of examinations and tests that may include:

• A review of your medical and family history.
• A complete physical examination.
• A neurological examination.
• A metabolic examination that includes blood and urine tests and, if needed, a cerebrospinal fluid test (spinal tap).
• DNA testing.

Other tests, depending on your symptoms and the affected areas of your body, might include:

• Magnetic resonance imaging (MRI) or spectroscopy (MRS) for neurological symptoms.
• Retinal exam or electroretinogram (ERG) for vision symptoms.
• Electrocardiogram (EKG) or echocardiogram for symptoms that affect your heart.
• Audiogram for hearing symptoms.
• Electroencephalogram (EEG) for seizures and related brain issues.

More advanced testing could include biochemical testing, which looks for changes in body chemicals involved in energy making. A healthcare provider may perform a biopsy where they take a sample of skin and/or muscle tissue to examine it under a microscope.

Are mitochondrial diseases difficult to diagnose?

Yes. Because mitochondrial diseases affect so many different organs and tissues of your body, and you may have many different symptoms, mitochondrial diseases can be difficult to diagnose. There’s no single laboratory test that can diagnose a mitochondrial disease. This is why a referral to a medical facility with physicians who specialize in these diseases is critical to making the diagnosis.

Treatment for a mitochondrial disease varies based on the type and your symptoms. Treatment could include:

• Taking medications to reduce symptoms, like medications to prevent seizures.
• Taking vitamins or supplements, like riboflavin, coenzyme Q10 and carnitine.
• Changing your diet (nutrition) and exercising.
• Physical therapy, occupational therapy or speech therapy.
• Wearing assistive devices like hearing aids.

There’s no cure for mitochondrial disease. Treatment focuses on preventing life-threatening complications. Treatment that works for one person may differ from what works to treat someone else with the same condition.

Are there side effects of the treatment?

Talk to your healthcare provider about side effects before starting treatment. They’ll discuss the side effects of your treatment specifically and what you should look out for. Each type of treatment comes with its own possible side effects.