• For Patients and Families

    Our bodies are made up of billions of small units called cells. Mitochondria (my-toe-kon-dree-uh) are tiny structures within cells that make energy for our bodies to use.  Mitochondria make more than 90 percent of the energy we need to live.  There are hundreds to thousands of mitochondria in each cell.

    Mitochondrial diseases are caused by mitochondria not functioning properly. When mitochondria are not working properly, the cell does not have enough energy and may be injured or die.  When many cells of the body do not have enough energy, whole organ systems (such as the nervous system or the digestive system) can be affected.  

  • About Mitochondrial Disorders

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    Mitochondrial diseases are caused by changes, or mutations, in genetic information (DNA).  DNA is like the instruction manual that tells our bodies how to grow and develop.  Cells have two types of DNA.  Most DNA is found in the nucleus (the innermost part of the cell) and is called nuclear DNA (nDNA).  A much smaller amount of DNA is present in the mitochondria and is considered mitochondrial DNA (mtDNA).  Mutations in nuclear DNA and mitochondrial DNA can cause mitochondrial disease.  These mutations can either be passed down in a family (inherited), or they can be new in a person’s DNA.  

    The organs of our body use different amounts of energy. Mitochondrial diseases cause the most damage to organs that use the most energy. The brain, heart, liver, muscles and kidneys all have large energy needs.  The endocrine (hormone-making) and respiratory (breathing) systems can also be affected. 

    Symptoms of a mitochondrial disorder can be different for each person.  These signs often overlap with many common conditions. Different mitochondrial disorders can be hard to tell apart, and two people with the same disorder may have very different symptoms. Symptoms of a mitochondrial disorder can include: 

    • Muscle weakness
    • Poor control over limbs
    • Poor growth
    • Heart disease
    • Liver disease
    • Diabetes
    • Seizures
    • Problems breathing and swallowing
    • Digestive issues
    • Vision and hearing problems
    • Developmental delay

    Mitochondrial disorders can be difficult to diagnose.  However, physicians who are experts in mitochondrial diseases use several tests to make a diagnosis. These may include:

    • Blood and urine tests
    • Eye exams
    • Heart function tests (such as an echocardiogram or an ECG)
    • Brain MRI
    • Hearing testing
    • Genetic testing

    Mitochondrial disorders can be passed on in families in different ways. The inheritance pattern depends on the disorder and whether the genetic change is in the nDNA or mtDNA. A patient’s family history can give clues about the inheritance pattern for a specific condition in a family. 

    Maternal Inheritance

    Some mitochondrial diseases follow maternal inheritance. This means that the condition is passed down on the mother’s side of the family. Only conditions caused by mutations in the mtDNA follow maternal inheritance. In this type of inheritance, all the children of an affected mother are at risk to inherit the mutation, but it is difficult to predict if the children will develop the disorder. Fathers who have the disorder do not pass it on to children.  This is because mitochondria are passed on from the mother in the egg cell during fertilization. 

    Autosomal Recessive Inheritance

    Some conditions follow autosomal recessive inheritance. This means that the condition is inherited from both parents. Both parents are healthy, but are carriers of the mutation.   If they both pass their copy of the mutation on to a child, then the child could be affected.

    Autosomal Dominant Pattern

    Other mitochondrial disorders can be inherited in an autosomal dominant pattern. This means that a person can have the condition if they inherit a mutation from one parent. The parent they inherited the mutation from often shows signs of the disorder.

    X-Linked Pattern

    Some mitochondrial disorders can be inherited in an X-linked pattern. This means that a healthy mother can pass the condition on to her sons, but not to her daughters.

    New Mutation

    In some conditions, the genetic mutations that cause the disease are usually not inherited. In those cases, the mutation is new, or sporadic, in that person. 

    Important Note

    It is important to talk with your doctor or genetic counselor about your family history.

    There are currently no cures for mitochondrial diseases. The purpose of treatment is to try to reduce symptoms and to keep the disease from becoming worse. Treatments may not work for all patients.  Some treatments such as vitamins and cofactors are useful for some patients.  Therapies such as physical or occupational therapy, speech therapy or respiratory therapy may also be helpful for some people. 

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  • Contact Us

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    Geneticists and genetic counselors are available to see patients for a consultation. Patients or physicians may call 513-636-4760, option 1, to request an appointment time.