Inherited mitochondrial diseases are genetic disorders that share as a common link defects in how cells make and regulate energy.
They can arise through defects in genes located in the nucleus or mitochondria. An estimated 2,000 defects in nuclear DNA and 200
defects in mitochondrial DNA have been identified that are pathogenic1.
Inherited mitochondrial diseases are clinically diverse and poorly understood. They can affect virtually any organ system in the
body. As the brain and muscle tissue use an extraordinary amount of energy, they are dramatically affected by these disorders.
Mitochondrial diseases often present with central nervous system manifestations, but they also result in a variety of other
significant clinical signs that include diabetes, heart failure, liver failure, deafness, blindness, renal insufficiency,
and muscle weakness and fatigue.
The incidence of mitochondrial disease is estimated at 1-5 in 10,000. However, this number may underestimate the true number
of people with mitochondrial disease. While new genetic screening tools have made detection of mitochondrial disease possible,
the majority of individuals with a clinical diagnosis of mitochondrial disease may not have a confirmatory genetic diagnosis.
Some estimates place the number of clinically diagnosed mitochondrial disease patients without a genetic diagnosis– so
called mitochondrial syndromes– at 10 times the incidence of genetically defined disease.
Science today is at the frontier of mitochondrial medicine. Certain diseases that previously lacked a known cause are now
being defined as mitochondrial in etiology. It is possible that in the future mitochondrial disease will be implicated in
additional diseases, such as in the biology of cancer.
1 http: //www.ninds.nih.gov/news_and_events/proceedings/20090629_mitochondrial.htm