1. The genetics of mitochondrial disease
By: Dr Natasha Gerbis

2. Mitochondria
Mitochondria play an essential role in cellular metabolism
Convert food into energy
The “batteries” of the cell

3. Mitochondria
Synthesize energy molecules called ATP via oxidative phosphorylation

4. Mitochondria
Present in every cell in the body, except for mature red blood cells
Some cells have only a few mitochondria
Other cells may contain up to 2000 mitochondria

5. Distribution of Mitochondria
Tissues that require lots of energy have lots of mitochondria
Muscles
Heart
Eyes
Ears
GIT
These are the tissues most often affected in mitochondrial disease

6. For example

7. Mitochondrial genetics
Over 1500 genes make up the genetic code responsible for producing one mitochondrion
37 genes are coded for by mitochondrial DNA
The rest are encoded by the nuclear genome

8. Mitochondrial disease inheritance
Mitochondrial disorders can therefore occur due to mutations that affectthe mitochondrial DNA or the nuclear DNA

9. Mitochondrial inheritance
Caused by mitochondrial DNA mutations
Mitochondrial DNA is inherited from the mother only

10. Mitochondrial inheritance

11. Mendelian Inheritance
Caused by mutations in the nuclear genome
Nuclear DNA is inherited from both parents
Since much of the mitochondrial DNA is encoded for by the nuclear genome, mitochondrial disease can also follow a mendeliajn pattern of inheritance.
That is to say, it can be inherited from the chromosomes.

12. Autosomal dominant http://www.natera.com/single-gene-testing
These are caused by mutations in dominant genes, which means you only need one copy of a faulty gene to express the disease
The person with the faulty gene has a 50% chance of passing it on to their children
Males and females are equally affected
Either the father or the mother can pass down the faulty gene down to the next generation

13. Autosomal recessive http://www.npr.org/
In autosomal recessive disease, you need two copies of a faulty gene to be present before the disease occurs

14. Sporadic disease Affected
Sporadic disease arises from a new mutation that occurs in the affected person. It is not inherited from either parent.
However, the patient affected by a sporadic mutation can pass the faulty gene on to their children.
These de novo mutations can occur in the mitochondrial genome or in the nuclear genome.
Affected

15. Questions?