What is Mitochondrial Disease?

Mitochondrial disease is a condition which affects the mitochondria, organelles located in the cells of all multicellular organisms. Because the mitochondria are responsible for generating a nucleotide which helps to transport energy between cells, they are considered the powerhouses of the human body. An interruption in mitochondrial function can lead to serious health problems. Since mitochondrial disease takes many forms, it can be difficult to diagnose, and there is currently no cure, although there are treatments for the condition.

The cells of multicellular organisms are unique because they have a number of specialized components called organelles. Each organelle performs a specific function related to cell life and growth. The mitochondria are elongated to spherical organelles which contribute to the production and regulation of energy in the body. They do this by producing adenosine triposphate (ATP), a nucleic acid used in the transfer of chemical energy between cells. Mitochondria also contribute to other tasks in the human body, and they contain a store of special DNA known as mitochondrial DNA or MTDNA. MTDNA is of particular interest because it is only passed down from the mother, so it can be used for genetic studies over many generations of a population.

When the mitochondria fail to perform properly, the result is mitochondrial disease. In a single cell, this will lead to cell injury and death, but the condition usually spreads, causing a problem for the host organism. Mitochondrial disease can lead to a myriad of symptoms, including muscle weakness, susceptibility to infection, growth and developmental delays, neurological problems, and gastrointestinal disorders. The condition is considered a metabolic disorder, since it impacts the body's ability to produce, store, and transfer energy.

Age at onset of mitochondrial disease varies. In some cases, the condition appears to be genetically transmitted, and it appears at birth or in early childhood. In other instances, mitochondrial disease appears much later, in adulthood, for reasons which are not always fully understood. The wide range of symptoms make it difficult to diagnose, since it can be confused with other conditions. Mitochondrial disease may also vary in severity, depending on which cells are affected by the condition.

Although the condition cannot be cured, the symptoms can be treated with various drugs and other modalities of treatment. Treatments may also help to delay the onset of the disease, or to arrest the spread in the body. The earlier mitochondrial disease is caught, the more effective treatment of the condition will be. Diagnosis can be difficult and expensive, requiring a battery of tests to ensure that it is accurate.