What is mitochondrial disorder?

Mitochondrial disease, or mitochondrial disorder, refers to a group of disorders that affect the mitochondria, which are tiny compartments that are present in almost every cell of the body. The mitochondria’s main function is to produce energy. More mitochondria are needed to make more energy, particularly in high-energy-demand organs such as the heart, muscles, and brain. When the number or function of mitochondria in the cell is disrupted, less energy is produced, and organ dysfunction results.

Depending on which cells within the body have disrupted mitochondria, different symptoms may occur. Mitochondrial disease can cause a vast array of health concerns, including fatigue, weakness, metabolic strokes, seizures, cardiomyopathy, arrhythmias, developmental or cognitive disabilities, diabetes mellitus, impairment of hearing, vision, growth, liver, gastrointestinal, or kidney function, and more. These symptoms can present at any age from infancy up until late adulthood.

Mitochondrial disease diagnosis

Every 30 minutes, a child is born who will develop a mitochondrial disorder by age 10. Overall, approximately 1 in every 4,300 individuals in the United States has a mitochondrial disease. Given the various potential presentations that may occur, mitochondrial disease can be difficult to diagnosis and is often misdiagnosed.

There are various methods to examine if an individual has mitochondrial disease. These include genetic diagnostic testing, genetic or biochemical tests in affected tissues, such as muscle or liver, and other blood or urine-based biochemical markers. However, our knowledge is still growing and we do not yet know all of the genes that could potentially cause mitochondrial disease.

Mitochondrial disease causes

Mitochondria are unique in that they have their own DNA called mitochondrial DNA, or mtDNA. Mutations in this mtDNA or mutations in nuclear DNA (DNA found in the nucleus of a cell) can cause mitochondrial disorder. Environmental toxins can also trigger mitochondrial disease.

Mitochondrial disease symptoms

Mitochondrial disorder symptoms include:

• Poor growth
• Loss of muscle coordination, muscle weakness
• Neurological problems, including seizures
• Autism spectrum disorder, represented by a variety of ASD characteristics
• Visual and/or hearing problems
• Developmental delays, learning disabilities
• Heart, liver or kidney disease
• Gastrointestinal disorders, such as severe constipation
• Diabetes
• Respiratory disorders
• Increased risk of infection
• Thyroid and/or adrenal dysfunction
• Dysfunction of the autonomic nervous system
• Neuropsychological changes or dementia characterized by confusion, disorientation and memory loss

Treatment for mitochondrial disease

Currently there is no highly effective treatment or cure for mitochondrial disorder. The management of mitochondrial disease is supportive therapy, which may include nutritional management, exercise and/or vitamin or amino acid supplements.

Knowing the underlying cause of your or your child’s condition will help your medical team determine the best course of treatment. Mitochondrial Medicine at Children's Hospital of Philadelphia (CHOP) works closely with your primary care physician, neurologist, and other specialists to manage your day-to-day medical needs.

What to Expect

Our team will provide relevant mitochondrial disease counseling based on your child’s diagnosis, including an overview of mitochondrial disease features and genetics.

Your child’s neurologist or primary care physician will manage the day-to-day medical concerns associated with mitochondrial disease.

Follow-up care

Long-term care may involve a variety of specialists, including neurologists, endocrinologists, ophthalmologists, audiologists, cardiologists and nephrologists.

For patients with mitochondrial disease with no known genetic cause, yearly follow-up appointments are typically recommended as mutations in new genes causing mitochondrial disease are discovered all the time.