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What is mitochondria disease? What does it have to do with autism, and are there treatments?
This week’s “Got Questions?” answer comes from Deepa Menon, MD, assistant medical director of the Center for Autism and Related Disorders, at Baltimore’s Kennedy Krieger Institute—an Autism Speaks Autism Treatment Network (ATN) site. Her research interests include metabolic and mitochondrial disorders and their association with autism.
Mitochondria are cell structures, or “organelles,” whose primary function is to supply a cell with energy. In essence, they turn sugar and fatty acids from food into the energy-carrying molecule adenosine triphosphate (ATP).
Virtually every cell in the body depends on ATP and mitochondria for energy. As a result, mitochondrial disorders can produce a wide variety of symptoms. The most common involve body systems that use a lot of energy. Muscles are a classic example, and mitochondrial dysfunction often produces muscle weakness and fatigue. When mitochondrial dysfunction affects the gastrointestinal system, symptoms can include constipation or diarrhea. When it affects the immune system, it can lead to frequent infections. Mitochondrial disorders can likewise cause failure to grow, kidney dysfunction and a many other medical problems.
The brain is another energy-demanding system. Here, mitochondrial dysfunction can produce such symptoms as developmental delay, hearing problems and seizures.
Over the last decade, there has been great interest in the possibility that mitochondrial disorders may underlie some of the symptoms of autism spectrum disorder (ASD). Currently we believe that around 5 to 10 percent of children with autism have mitochondrial dysfunction as the underlying cause of their symptoms.
Research suggests that many children diagnosed with autism and underlying mitochondrial dysfunction experienced regression following a simple childhood illness (ear infection, common cold, etc.) or other cause of fever or inflammation. Regression refers to a loss of developmental skills such as language or motor abilities. It may be accompanied by other symptoms of mitochondrial disorder such as fatigue, gastrointestinal distress, seizures and/or motor delays.
Laboratory testing of blood samples and urine show that many of these children (with ASD and mitochondrial dysfunction) have abnormally high levels of certain amino acids and cellular waste products. This suggests that their cells are generating energy inefficiently with an excess of damaging byproducts.
When a child is diagnosed with ASD and mitochondrial dysfunction, treatment goals include a bolstering mitochondrial activity and protecting the mitochondria from further damage. Parents and affected individuals may be counseled to avoid (as much as possible) situations that stress mitochondria. Examples of these stresses include going for long periods between meals (prolonged fasting), infections that produce fevers, inflammation associated with dietary sensitivities and certain medications such as the antipsychotic haloperidol (Haldol), which is known to impair mitochondrial function.
Supportive treatment can include a prescription nutrient mixture containing the protein L-carnitine and the B-vitamin pantothenate, which is thought to bolster mitochondrial activity. This prescription mixture usually contains additional nutrients such as thiamine, nicotinamide, lipoic acid, and vitamins C and E. Coenzyme Q10 may be added for those who show low levels of CoQ10 on testing.
[Editor’s note: Autism Speaks continues to support research into the association of mitochondrial disease and autism and their effective treatments. For more information on these and other funded studies, please explore our Grant Search portal, here.]
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