WHAT IS MITOCHONDRIAL DISEASE?

If your power goes out in your home, your food spoils, your heating/air conditioning does not work, and you're left in darkness. You call your local power supplier to report the problem.

The Mitochondria is the part of the cell responsible for energy production. It is very much like the power supplier that provides energy to your home. If the mitochondria is defective, your body cannot function as it should. The brain becomes impaired, muscles start to twitch spastically and weaken, the heart does not pump correctly, vision becomes impaired and the list can go on. For many children and adults with mitochondrial disease, this is exactly what they experience.

To give you a more "scientific explanation", look at this picture of a mitochondrion, showing you the basic structure of a mitochondrion, which are present in every cell in our bodies:

Mitochondria are the powerhouses of the human cell; they convert the energy stored in sugars and fats into adenosine triphosphate (ATP), the essential energy molecule of all animals.

This energy production is carried out on a complex folded inner membrane of the mitochondria (see the picture above). Every muscle cell is filled with mitochondria, combining sugars or fats with oxygen to yield water and ATP. Without this ATP, we would die, having no "power" left. Mitochondrial cytopathies have a diverse range of symptoms, and span many (all) organ systems.

There is such a large number of biochemical and genetic defects, that currently a predictable clinical course does not exist. Using the description above, the analogy of a power supplier not supplying enough energy is a good one. The mitochondrion in the above picture is only one of many in your cells.

The reason people manifest with SO many different problems is based on the percentage of "bad" mitochondria that get assigned to that part of the body. In our own family, some kids obviously have a higher percentage of bad mitochondria in their muscles than some of their siblings, while others have more brain (neurological) problems. This chart shows you a basic idea of how this can happen. Keep in mind that men do not contribute mitochondria, but that does not mean that only the mother causes mitochondrial disease, as there can be mutations.

Here's the simplest way to explain what happens. The food we eat gets broken down and assigned in various fashion. The fats and sugars go through processing, and there's quite a bit involved in this. If you get into this stuff more, you'll hear all about the respiratory chain and ATP, which is the end result, or energy. The mitochondria in a cell have to go through five "complexes" to create energy. An error in any of those complexes is bad, but obviously there can be varying degrees of how big the error is, and where it occurs in the energy making process. Mitochondria are responsible for producing 95% of the energy that's needed for our cells to function. In fact, they provide such an important source of energy that a typical human cell contains hundreds of them.

A mitochondrial disease can shut down some or all the mitochondria, cutting off this essential energy supply. Because muscle cells and nerve cells have especially high energy needs, muscular and neurological problems are common features of mitochondrial disease. MDA uses this picture to help illustrate:

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 What are Mitochondria?

Mitochondria are tiny organelles found in almost every cell in the body.

• They are known as the "powerhouse of the cell."
• They are responsible for creating more than 90% of cellular energy.
• They are necessary in the body to sustain life and support growth.
• They are composed of tiny packages of enzymes that turn nutrients into cellular energy
• Mitochondrial failure causes cell injury that leads to cell death. When multiple organ cells die there is organ failure.

What is Mitochondrial Disease?

• Mitochondrial disease is a chronic, genetic disorder that occurs when the mitochondria of the cell fails to produce enough energy for cell or organ function.
• The incidence about 1:3000-4000 individuals in the US. This is similar to the incidence of cystic fibrosis of caucasian births in the U.S.
• There are many forms of mitochondrial disease.
• Mitochondrial disease is inherited in a number of different ways
• Mitochondrial disease presents very differently from individual to individual.
• There may be one individual in a family or many individuals affected over a number of generations.

What are the Symptoms of Mitochondrial Disease?

The severity of mitochondrial disease symptoms is different from person to person. The most common symptoms are:

• Poor Growth
• Loss of muscle coordination, muscle weakness
• Neurological problems, seizures
• Autism, autistic spectrum, autistic-like features
• Visual and/or hearing problems
• Developmental delays, learning disabilities
• Heart, liver or kidney disease
• Gastrointestinal disorders, severe constipation
• Diabetes
• Increased risk of infection
• Thyroid and/or adrenal dysfunction
• Autonomic dysfunction
• Neuropsychological changes characterized by confusion, disorientation and memory loss.

How common are mitochondrial diseases?

• About one in 4,000 children in the United States will develop mitochondrial disease by the age of 10 years.
• One thousand to 4,000 children per year in the United Sates are born with a type of mitochondrial disease.
• In adults, many diseases of aging have been found to have defects of mitochondrial function.
• These include, but are not limited to, type 2 diabetes, Parkinson's disease, atherosclerotic heart disease, stroke, Alzheimer's disease, and cancer. In addition, many medicines can injure the mitochondria.

What causes mitochondrial disease?

For many patients, mitochondrial disease is an inherited condition that runs in families (genetic). An uncertain percentage of patients acquire symptoms due to other factors, including mitochondrial toxins.

It is important to determine which type of mitochondrial disease inheritance is present, in order to predict the risk of recurrence for future children. The types of mitochondrial disease inheritance include:

• DNA (DNA contained in the nucleus of the cell) inheritance. Also called autosomal inheritance.
  • If this gene trait is recessive (one gene from each parent), often no other family members appear to be affected. There is a 25 percent chance of the trait occurring in other siblings.
  • If this gene trait is dominant (a gene from either parent), the disease often occurs in other family members. There is a 50 percent chance of the trait occurring in other siblings.

How is Mitochondrial Disease Treated?

• Treatment consists of vitamin therapy and conserving energy.
• The goal is to improve symptoms and slow progression of the disease.
• Conserve energy
• Pace activities
• Maintain an ambient environmental temperature
• Avoid exposure to illness
• Ensure adequate nutrition and hydration

What are the Challenges of living with Mitochondrial Disease?

• Affects multiple organs, affects multiple family members, affects multiple generations.
• Lack of awareness and understanding of the disease
• Families are continuously forces to expend their very limited energy to explain their disease, advocate for themselves and fight for services.
• Mitochondrial disease is often an " invisible disease."
  • Good day - patients look fine and healthy. They have more energy and appear rested.
  • Bad day - - patients appear tired to significantly ill. They are obviously fatigued and/or have significant illness. Repeated "bad days"often lead to decompensation and patients have difficulty returning to baseline.
• Mitochondrial disease is unpredictable. Day to day, hour to hour patients can develop symptoms and their stability can be threatened.
• Difficulties establishing a diagnosis interfere with a patient's ability to obtain adequate recognition, medical care, adequate insurance coverage, healthcare supports and disability services.
• Lack of understanding of the disease and misinterpretation of symptoms can lead to misdiagnosis. Further progression of symptoms can occur if the symptoms are missed and opportunities for treatment and support are not recognized.
• An individual can become symptomatic at any time in life despite the fact that it is inherited.
• It is difficult to diagnose.

source: www.mitoaction.org