Mitochondria are known as our body's power plants. They burn the sugars, fats and proteins in our diet to generate the energy that our body needs to function normally. When our mitochondria don't function correctly this can impact our health.
Disorders of mitochondrial energy generation can be caused by primary mutations in mitochondrial DNA (point mutations and single deletions) and by nuclear gene disorders. A subset of nuclear gene disorders result in secondary mutations in mitochondrial DNA (multiple deletions or depletion of mitochondrial DNA).
Testing for mitochondrial disorders is performed using molecular DNA testing and biochemical/enzymology methods.
The best method for testing depends on the age of onset, clinical symptoms, family history and results of screening tests (metabolic and imaging). Expert input from a clinical geneticist or suitable specialist is usually needed to determine which testing is the most appropriate.
Testing is performed on blood, urine, saliva, skeletal muscle, liver, cardiac muscle, chorionic villus (CVS) or cultured skin fibroblasts depending on the clinical presentation.
Our tests detect a number of different mitochondrial disorders, including:
- Leigh syndrome
- Alpers syndrome
- Kearns Sayre syndrome
- Pearson syndrome
- Leber hereditary optic neuropathy,
- Mitochondrial hepatopathy
- Mitochondrial cardiomyopathy
- Other mitochondrial encephalopathies
VCGS offers a range of different test options, shown below.
See our test option summary table for all sample requirements, reporting times and costs.
Testing is performed when an individual is suspected of having a mitochondrial disorder. This can be at any age but often occurs in the newborn period or infancy. Testing can also be performed in early childhood, adolescence, in young adults or in middle age. This is a specialised test that is usually ordered by a paediatrician or other medical specialist.
Please provide the following clinical details (if available) to enable optimal interpretation:
- Patient name, medical record no., date of birth, date of sample, delay between death and freezing if relevant.
- Full clinical summary and family history with pedigree.
- Include copies of relevant investigations
- urine organic & amino acids
- tissue histology (including electron microscopy & enzyme histochemistry)
- summary of CT, MRI or MRS studies of brain.
- Paired plasma lactate & pyruvate levels; multiple estimations preferred.
- Paired CSF lactate & pyruvate levels, preferably with blood levels obtained at about the same time.
What are mitochondria?
Mitochondria are organelles in all our cells that take part in a wide range of metabolic pathways. They are the body's power plants that burn fuels (sugars, fats and proteins) to generate energy in the form of a small molecule called ATP.
The mitochondrial respiratory chain or oxidative phosphorylation system is the central energy generating pathway in cells. It comprises five enzyme complexes located in the mitochondrial inner membrane. More than 1000 genes are required for normal mitochondrial function. However, a unique feature of the mitochondrion is that it contains an additional genome (mitochondrial DNA), located within the mitochondrion itself.
What are the symptoms of a mitochondrial disorder?
The symptoms of mitochondrial disorders vary widely. Some symptoms of inherited mitochondrial disorders include lethargy, failure to gain weight, developmental delay, seizures, diabetes, muscle weakness, deafness and loss of vision.
What treatments are available for a mitochondrial disorder?
Treatment focuses on management of specific symptoms, ensuring good nutrition, aggressive management of infections and identifying patients for whom specific treatment options are available. For some mitochondrial disorders, there are no effective treatments.
How much experience does the VCGS Mitochondrial laboratory have?
The laboratory has acted as the Australasian referral centre for diagnosis of mitochondrial disease in children for more than two decades. We have diagnosed more than 600 children. The laboratory is tightly integrated with the Murdoch Childrens Research Institute and has a high international profile in mitochondrial disease. Our achievements include translating knowledge of mitochondrial DNA genetics into reproductive options for families, defining the most widely used diagnostic criteria for mitochondrial disorders, defining the epidemiology of childhood mitochondrial diseases and improving diagnosis and discovery of new 'disease' genes through Next Generation DNA sequencing. Either in house or through collaboration with national and international colleagues, we have identified mutations in more than 60 different disease genes, 20 of which we were the first to identify.