Mitochondrial diseases are a group of disorders caused bydysfunctional mitochondria, the organelles that generate energy for the cell. Mitochondrial diseases are sometimes (about 15% of the time) caused by mutations in the mitochondrial DNA that affect mitochondrial function. Other mitochondrial diseases are caused by mutations in genes of the nuclear DNA, whose gene products are imported into the mitochondria (mitochondrial proteins).
This type of inheritance, also known as maternal inheritance, applies to genes in mitochondrial DNA. Because only egg cells contribute mitochondria to the developing embryo, only mothers can pass on mitochondrial conditions to their children.
Examples of this type of disorder are
Mitochondrial diseases are usually detected by analysing muscle samples, where the presence of these organelles is higher. The most common tests for the detection of these diseases are: