Mitochondria are organelles found in most eukaryotic cells. When mitochondria are dysfunctional it can cause a mitochondrial disease. Of these mitochondrial diseases, 15% are caused by problems in the mitochondrial DNA. Mitochondrial DNA is inherited from the mother and not the father as mitochondrial DNA is passed to offspring through the egg cell. Egg cells contain hundreds of thousands of mitochondria so during cell division most mitochondria come from the egg cell. Sperm cells do contain a few hundred mitochondria, however this is insignificant compared to the large egg cell.
The prevalence of mitochondrial diseases is relatively low with 1 in 4000 children developing a mitochondrial disease by the age of 10. Furthermore, this is not simply one disease: there are many types of mitochondrial disease, most of which are quite rare. Also, problems with mitochondria can be associated to other diseases such as stroke, Alzheimer’s and cancer.
Treatments for mitochondrial diseases are limited due to the complex nature of the mitochondria, the way they are passed on, and problems with asymptomatic patients who pass on the genes but who aren’t identified until they have passed it on to the next generation.
A future possible treatment for mitochondrial disease would be from 3 person IVF treatment. This would work if a mother is diagnosed with a mitochondrial disease, and rather than passing on the disease to her children, her and her partner can under go 3 person IVF treatment. This would mean that an egg donor would provide the mitochondria. 3 person IVF is a very new treatment option and was only approved by the UK government on the 26 June 2013.