How did I get it?

Mitochondrial disease can be classed as primary or secondary. Generally, when we talk of mitochondrial diseases, we are usually talking about the primary type. That is, the type caused by a ‘hiccup’ in the genes used to make the mitochondria.

The secondary type is always related to another illness, an illness that has caused the mitochondria to malfunction despite the normal formation of mitochondria initially.

Primary mitochondrial diseases are therefore genetic disorders and may present in a number of different ways: 

  1. there is a clear family history of the known mitochondrial disease

  2. there is a family history of peculiar, undiagnosed illnesses that could be mitochondrial disease

  3. family members appear well and healthy but are unknowingly carrying the genetic defect which is passed onto their children, or

  4. mitochondrial genes are mutated for the first time in an individual who may become unwell themselves or possibly pass it onto their children who become unwell later.

Therefore, due to the broad range of presentations and genetic defects of this illness, it can originate at any point in time.

In summary, frequently it is carried down only on the mother’s side (see diagram below), infrequently only on the father’s side, it may have required both parents for it to be carried down, or it may be mutated for the first time.