Mitochondria... I've got the POWER!

The mitochondria are the powerhouses of the body. They convert food, air, water, etc. in to energy (ATP - adenosine triphosphate) approximately 90% of the bodies energy. If there is a flaw or missing piece to the puzzle then the body suffers. Think of a brown out - it would be like trying to run Atlanta's energy needs on a small rural towns power grid. Mitochondrial deficiency can affect any organ. Sometimes it can be something minor like allergies or minor asthma or complete respiratory failure. From minor reflux to to major dismotility of the whole GI tract.
A mitochondrial disorder/disease can appear at any age and to any degree of severity. Many times mito goes undiagnosed and sometime is not diagnosed until death. Even those that are spotted by a physician may go weeks, months or years before getting a solid diagnosis. 
Currently there is no cure only treatment for symptoms. Which are usually supplements and not covered by most insurance companies. Also there is only 1 of the 40 different types of mito that is covered by any kind of clinic - Mitochondrial Myopathy affects the muscles severely and patients can be seen in MDA clinics. 
Mitochondrial disease is "rare" but not. Many in the medical field have not heard of mito or if they have they know very little about it, yet it is as common as Cystic Fibrosis. It was once thought that mito could only be inherited from the mother (MtDNA - Mitochondrial DNA) but there is also autosomal recessive - a defective gene from each parent and finally there is denovo which is a singular genetic fluke. 

For more information:
http://www.mda.org/publications/mitochondrial_myopathies.html
http://www.umdf.org
http://www.mitoaction.org/