When a person has Mitochondrial Disease, the mitochondria in the cells are not producing enough energy for the cell. Sometimes they do not work at all, and sometimes they are just not very efficient.
If a cell does not get enough energy (ATP) it cannot function properly.
There is a huge variety in the symptoms and severity of Mitochondrial Disease. It depends on how many cells are affected, and where they are in the body.
Every person with Mitochondrial Disease is affected differently. Each individual affected will have a different combination of mitochondria that are working and not working within each cell.
However, there are times when particular body systems are affected in a recognisable pattern and these have particular names, for example Alpers, Leigh’s disease, MELAS and MERRF. The commonest parts of the body affected are those that have the highest energy demands: brain, muscle, liver, heart and kidney.
If a lot of mitochondria in the body are affected in the important body organs, like the brain, mitochondrial disease can be very serious.
The symptoms of Mitochondrial Disease are usually progressive in body systems where the cells have a high demand for energy, such as brain cells.