Summary

Your body is made of 40 trillion cells, each with a copy of your unique genetic code, like a collection of recipes passed down through generations.
Genetic testing acts like a spell-checker for your genetic instructions, finding "typos" that could lead to diseases.
Tests include Whole Genome Sequencing (WGS), Whole Exome Sequencing (WES) and Mitochondrial genome sequencing. Changes in both nuclear and mitochondrial DNA can be detected by performing either WGS alone or WES plus mtDNA sequencing.
A genetic diagnosis can provide certainty, faster diagnosis, and enables monitoring, proactive management, and early intervention for better quality of life.
Before testing, consider fears of discrimination, emotional impact, and costs. Test results can indicate pathogenic changes causing disease, benign changes, or uncertain variants, requiring consultation with a genetics specialist.

On this page, you'll find:

Reasons for testing

Types of genetic tests

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DNA, genes, chromosomes, and proteins

Your body is made up of 40 trillion cells, and each cell contains a copy of your unique genetic information. A genome refers to a complete set of instructions, either mitochondrial or nuclear.¹ This is like having two bookcases, full of recipes, handed down through generations.

The nuclear genome is made up of the nuclear DNA (nDNA). This is like the biggest bookcase that's located within the nucleus. It is the control centre of your cells and contains most of your genetic information. nDNA is inherited from both parents and made up of 20,000-25,000 genes,² providing the instructions (or recipes) for things like your hair or eye colour.

Your body has many genes with different roles. Genes are like the recipes within each recipe book. Around 1,100 nDNA genes help with mitochondrial function.³

In all your cells, genes are found on chromosomes. Each chromosome is like one recipe book. We usually have 46 chromosomes of nDNA to make 23 pairs within each cell's nucleus. Thousands of genes send messages to your cells to make proteins. These proteins are crucial for almost every task in your cells.¹

The mitochondrial genome is made up of the mitochondrial DNA (mtDNA) which is a much smaller bookcase found in the mitochondria. Each mitochondrion have 37 genes. These genes give instructions (or recipes) for making energy.²

Watch an introduction to genes, genomes, and genetic instructions to learn more

You can think about our genome of being made up on two bookcases full of recipes. One bookcase is for nuclear DNA, one for mitochondrial DNA. You can think of each recipe being a single gene. Some of the recipes are grouped into books called chromosomes. Proteins are what made when the recipes are followed. A genetic change is when a ‘typo’ or an error occurs within the books.

Genetic testing explained

DNA is made up of a sequence of A, G, C and T. These letters pair up to form the "rungs" of the twisted ladder shape that DNA is known for. Genetic testing is when a lab examines the sequence of A, G, C and T to identify any changes.

A diagram of nuclear DNA, showing the sequence of A, G, C, and T. Which stand for adenine, thymine, guanine, and cytosine to form the twist rungs of the ladder nuclear DNA is known for.

Genetic testing is like a spell-checker for your body's instruction books. It can find 'typos' or other changes in the DNA sequence that could cause health conditions. Many changes are found in genes, and most are normal, making people different from each other. Some types of genetic changes cause genetic conditions like mito.

Health professionals use various tests to diagnose mito. This can include looking for certain chemicals in blood or urine and looking at cells from different body parts such as from a muscle biopsy. Genetic testing is a useful tool and can be used early in the process of diagnosing mito.⁴^,⁵

The results of a genetic test can also determine your chance of developing mito or passing it on to any children you have. Occasionally, a genetic change is a new occurrence in the family that hasn't been inherited, referred to as a sporadic or de novo genetic change.

Genetic testing is usually ordered by a specialist doctor, not your GP. You can speak to your specialist or ask for a referral to a clinical genetics service. Clinical genetics services can provide up-to-date information on testing options and provide genetic counselling services to help you make an informed decision about testing. Medicare funding is only available for genetic tests for mito when ordered by a specialist doctor. Learn more about genetic testing and mito.

What is tested?

In most cases, health professionals arrange genetic testing on a blood sample. However, a urine sample or a sample from another part of the body can sometimes give more information about genetic changes. The type of sample may depend on the type of test being done.

What are the reasons for genetic testing?

Diagnostic testing

Presymptomatic testing

Genetic carrier testing

Genetic carrier screening

Is used to tell future parents whether they have an increased risk of having a child with some specific genetic conditions. It's usually done before pregnancy and is a test that examines the genes of future parents. It looks for any gene changes that may increase the risk of future parents having a child with a genetic condition. Some, but not all, carrier screening tests include some types of mito.

Genetic carrier screening is explained in more detail here.

Prenatal testing

Preimplantation testing

When you have a family member who knows their genetic change

If you have a close relative with a genetic change that can cause mito, your health professional can test for this specific change in other family members. They may also recommend genetic counselling to help you understand your chance of developing mito.

What are the different types of genetic tests?

Many tests can check for changes in your genes, chromosomes, or proteins. In Australia, whole genome sequencing of nDNA and mtDNA is subsidised by Medicare and is the type of test most likely to find a genetic change if a person has mito. However, even this type of testing can sometimes not find a gene change known to cause mito.

Your health professional will consider which type of testing is best for you. They will consider your symptoms and family history. If your health professional has a good idea of the possible type of mito causing your symptoms, they may use a test that only looks at a few specific genetic changes.

Learn more about categories of genetic testing

Whole genome sequencing (WGS)

WGS is like reading every recipe book from cover to cover, identifying the order of these letters in the nDNA. WGS can also include the mtDNA genome when requested. It can see all your genetic information, including the parts for making proteins and the spaces in between.

It reads all three billion letters of your genetic code to find a change. WGS provides a wealth of information. Still, sometimes, it can be challenging to determine if the genetic changes found are causing mito. This is because of other genetic changes that are not known to cause a genetic condition.

Benefits of WGS

Can identify genetic changes in both nuclear and mitochondrial DNA
Can detect a wide range of changes in DNA e.g., removing or adding an extra copy of a page in the recipe book rather than just a single letter
Simplifies the diagnostic process
Tells you about the chance of passing on the genetic change
Medicare funding for WGS is available

Whole exome sequencing (WES)

The parts of your DNA that provide instructions for making proteins are called 'exons'. These exons make up about 2% of your entire DNA and together they form what we call the 'exome'.

The exome is like the collection of the most important steps in each recipe. It's the part that’s understood the best, and where most of the nDNA gene changes that are known to cause mito, and many other diseases, are found. WES looks for changes that could cause mito.

While a lot is known about the exons, some parts don't provide instructions (also known as code) for proteins. Changes in these non-coding regions can cause types of mito too. That's why WGS might be better for some people with suspected mito.

Benefits of WES

Focuses on the most important parts of your DNA that give instructions for making proteins
Can be very useful to diagnose mito when also combined with sequencing of mtDNA
WES is offered by more Australian labs than WGS
Medicare funding for WES is available

Mitochondrial genome sequencing

If you have clear symptoms of mito caused by a change in mtDNA, a genetic test can check just the mtDNA genes. This is like reading every recipe, but only on the bookshelf containing mtDNA. The gene sequence is read and checked for changes, a process called sequencing the mitochondrial genome.

This test is often combined with WES, as WES doesn’t reliably detect changes in the mtDNA genes.

Benefits of Mitochondrial sequencing

Specifically, proofreads the mtDNA
Medicare funding for mitochondrial sequencing is available

Targeted panel testing

If you have symptoms that are linked with a specific type of mito, a targeted panel test may be useful. Targeted panel testing looks at a small group (panel) of genes linked to a specific genetic condition such as MELAS or LHON. If this test does not find a genetic change your health professional may suggest WGS or WES.

Benefits of target panel testing

Results for targeted panel tests are often available quicker
Target panel testing is available at more labs compared to other tests in Australia
Target panel tests can also be cheaper if you are paying directly for the test, such as if you are not in a public hospital and not eligible for Medicare

Because of the large number of genes that can cause symptoms of mito, targeted panel testing may not be recommended by your health professional. This is because WGS covers so many more genes (at least 300) compared to panel tests (approximately 20).

Cascade testing

What is direct-to-consumer genetic testing?

Companies sell genetic testing services directly to the public without a health professional's involvement. The testing services are often done overseas. These labs don't have to follow strict Australian regulations, unlike clinical labs in Australia, which have to be accredited by The National Association of Testing Authorities (NATA).

The Mito Foundation encourages individuals to work with their health professionals for genetic testing to ensure that they receive accurate results and evidence-based information.

The differences between clinical versus direct-to-consumer genetic testing is explained here.

What are the benefits of genetic testing?

There are different ways that mito can be diagnosed. You can learn more about the categories of diagnosis here.

Benefits of a genetic diagnosis include, but are not limited to:

Provides certainty of a diagnosis

A genetic diagnosis, combined with signs and symptoms, can confirm mito with more certainty than a clinical diagnosis.⁶ This diagnosis can be a relief for many, as it removes the stress of uncertainty and the constant search for answers. Being diagnosed allows individuals to learn how to manage their symptoms, improve their health, and continue their daily activities. Even if the diagnosis isn't what they hoped for, it's usually more helpful than not knowing. The clarity a diagnosis gives hope in the complex journey of living with mito.⁷

Faster and less invasive tests

Genetic testing can be a quicker and simpler way to diagnosis, as it means less time and money spent on multiple appointments.

Genetic testing can mean that invasive tests, specifically muscle biopsies may not be needed as often for diagnosing mito. A faster diagnosis can allow people with mito to concentrate on managing their symptoms and improving their health rather than worrying about the next test or appointment.^6-9

Enables monitoring and earlier management

Members of the mito community often express that the uncertainty of the future is one of the most challenging parts of living with mito.

Health professionals are familiar with the common types of mito and how they can progress. However, it may still be difficult for your health professional to predict exactly how mito may impact you in the future. They use pre-emptive monitoring to track the progression, allowing for earlier management.

In less-known types of mito, individuals can be monitored to gain insight into the progression. However, more research is needed to build the natural history data (progression of mito in an individual over time without treatment) for different types of mito. The natural history data provides a baseline which the effectiveness of a new drug or intervention can be measured against in clinical studies. Helping researchers better understand mito and improve the quality of life for those living with mito.⁷^,⁸

Enhances proactive management and early intervention

While there are no cures and limited treatments for mito, early intervention and proactive management can play a significant role in managing symptoms or slowing the progression of mito.

Knowing how to manage symptoms during stressful times can improve quality of life, and understanding the risk of sudden symptoms, like stroke-like episodes, can help manage mito. An accurate diagnosis also helps avoid substances known to worsen mito. Therefore, genetic testing for an early and accurate diagnosis is crucial for better management and improved quality of life.⁷^,⁹

Enables early diagnosis for family members

Enables reproductive planning for people impacted by mito

Access to emerging therapies

There has been a significant growth in the development of new treatments for mito, including a surge in gene therapy development. Over 130 clinical trials involving pharmacological intervention for mito are registered on Clinicaltrials.gov. Most of these trials require people to have a confirmed genetic diagnosis before they can participate in them. In the future, we expect that many new treatments for mito will target specific genetic changes.⁷

Identifying a non-mito cause of signs and symptoms

What else should I think about before having a genetic test?

Fear of discrimination

The fear of genetic discrimination holds many people back, especially when it comes to getting life insurance. Some people worry that genetic tests could lead to unfair treatment from insurance companies, stopping them from accessing genetic testing.¹⁰

Insurance companies may refuse to provide cover based on a genetic diagnosis. For this reason, some mito community members choose to ensure they have appropriate cover before receiving a genetic diagnosis, preventing their application being refused, or potentially paying higher premiums.

Impact on insurance premiums

Emotional impact

Cost and eligibility

How long does genetic testing take?

The time it takes to receive a genetic test result for mito can vary depending on the type of test and the lab. Generally, it can take several months. For example, the Victorian Clinical Genetics Services (VCGS) states that tests can take 3-4 months.

The time taken can be shorter if there is urgent medical care that can be informed by the results of the genetic test. Testing may be prioritised if the outcome of the genetic test will inform reproductive options or if symptom progression is significant. In some research projects, urgent genetic testing can be done in just a few days.¹²^{, 13}

The time taken to receive results can also be longer when a genetic change is found, but it is not yet clear whether this change causes mito. You should ask your health professionals about the expected times when the sample is provided for testing.

What does my genetic test result mean?

The test result will explain if a genetic change has been found and if this change is likely to cause mito. Test results are complex and difficult to understand. You should speak to a health professional to understand what your genetic test result means for you.

A pathogenic change is a genetic change known to stop the gene from working correctly. Pathogenic means that it can cause disease. Therefore, this means that the genetic change can lead to mito.

Genetic testing might find a genetic change that is not disease-causing, these are called a benign change. These changes are usually not detailed in the genetic report and suggest that the genetic change cannot cause mito.

Sometimes, the genetic test result will be uncertain. An uncertain variant means a genetic change has been found, but whether it causes mito is unclear. DNA contains a lot of information, making interpreting the genetic information challenging.

Genetic test results can be reclassified, meaning the result might change over time. This happens when additional information or research gives the lab new clues about a genetic change. If the test result is uncertain, this result might change in the future.

A health professional specialising in genetics will interpret the genetic test results and consider other test results, such as blood or tissue tests and family history.

It's recommended to talk to your health professional for more detailed, personalised advice based on your unique circumstances and needs. They can also guide you through any decisions that need to be made based on the results. Learn more about genetic counselling and mito.

How much does genetic testing cost?

The best way to access genetic testing in Australia is by seeing a specialist. They should be experienced in this area, such as a mito clinic or a clinical genetics service.

If you are being seen in a public hospital, you do not have to pay for any testing. You may pay some out-of-pocket costs for testing if you are being seen in a private hospital or seeing a specialist privately.

cost of a genetic test for mito will be different depending on:

Which type of testing is best suited for each situation
Which lab is doing the test
Whether you are eligible for funding under Medicare or through your private health insurance.

You should discuss the cost of genetic testing with your health professional to understand whether the test will cost you any money.

Which Australian labs offer genetic testing for mito?

This list may be useful for health professionals when requesting a genetic test. This list is based on information provided to Mito Foundation and my be incomplete. We encourage pathology services to contact us with any additional or updated information.

Victorian Clinical Genetics Service (VCGS)

Pathology Queensland

Helpful resources

An introduction to DNA, RNA, genes and chromosomes is a useful resource published by the Centre for Genetic Education.
Genetic and Genomic Testing is a useful resource published by the Centre for Genetic Education.

Video resources

References

Centre for Genetics Education. An introduction to DNA, RNA, genes and chromosomes2021 20th November 2023. [Available from: https://www.genetics.edu.au/PDF/DNA_RNA_genes_and_chromosomes_fact_sheet-CGE.pdf.]
Lakna. Difference Between Mitochondrial DNA and Nuclear DNA 2017 [Available from: https://pediaa.com/difference-between-mitochondrial-dna-and-nuclear-dna/].
Gonçalves VF. Mitochondrial genetics. Mitochondria in Health and in Sickness. 2019:247-55.
Mavraki E, Labrum R, Sergeant K, Alston CL, Woodward C, Smith C, et al. Best practice guidelines for the molecular diagnosis of mitochondrial disease. Ratified; 2020.
Schon KR, Horvath R, Wei W, Calabrese C, Tucci A, Ibañez K, et al. Use of whole genome sequencing to determine genetic basis of suspected mitochondrial disorders: cohort study. Bmj. 2021;375.
Grier J, Hirano M, Karaa A, Shepard E, Thompson JLP. Diagnostic odyssey of patients with mitochondrial disease: Results of a survey. Neurol Genet. 2018;4(2):e230.
Murray S SC. MSAC application 1675 – Whole Genome Sequencing for the diagnosis of mitochondrial disease. 2021.
Soldatov VO, Kubekina MV, Skorkina MY, Belykh AE, Egorova TV, Korokin MV, et al. Current advances in gene therapy of mitochondrial diseases. Journal of Translational Medicine. 2022;20(1):562.
Wu Y, Balasubramaniam S, Rius R, Thorburn DR, Christodoulou J, Goranitis I. Genomic sequencing for the diagnosis of childhood mitochondrial disorders: a health economic evaluation. European Journal of Human Genetics. 2022;30(5):577-86.
Tiller J, Gleeson P, McInerney-Leo A, Keogh L, Nowak K, Barlow-Stewart K, et al. The A-GLIMMER (Australian Genetics & Life Insurance Moratorium: Monitoring the Effectiveness and Response) Project: Final Stakeholder Report. 2023.
Australian Government Department of Health and Aged Care. $148 million in new Medicare rebates for genetic testing 2023 [Available from: https://www.health.gov.au/ministers/the-hon-mark-butler-mp/media/148-million-in-new-medicare-rebates-for-genetic-testing.]
Akesson LS, Eggers S, Love CJ, Chong B, Krzesinski EI, Brown NJ, et al. Early diagnosis of Pearson syndrome in neonatal intensive care following rapid mitochondrial genome sequencing in tandem with exome sequencing. European Journal of Human Genetics. 2019;27(12):1821-6.
Lunke S, Bouffler SE, Patel CV, Sandaradura SA, Wilson M, Pinner J, et al. Integrated multi-omics for rapid rare disease diagnosis on a national scale. Nature Medicine. 2023:1-11.

Disclaimer: Resources provided by the Australian Mitochondrial Disease Foundation Limited (Mito Foundation), offers general information and is not a substitute for medical advice. It is essential to assess the suitability of the content for your individual circumstances and make decisions based on your medical condition. The information’s accuracy is subject to change, and we do not guarantee ongoing currency or availability. While efforts are made to ensure accuracy, Mito Foundation is not obligated to provide updated information. The copyright for this document and its content belongs to, or is licensed to, Mito Foundation, and reproduction without prior written consent is prohibited.

Author(s): Mito Foundation
Reviewer(s): David Thorburn BSc(Hons) PhD FHGSA FFSc(RCPA) FAHMS, Suzanne Sallevelt MD PhD FRACP and members of the mito community.
Version: 2.1
Date published: 9 April 2024
Last revised: 6 June 2025

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Genetic testing and mito

Summary

On this page, you'll find:

Prefer to listen?

DNA, genes, chromosomes, and proteins

Genetic testing explained

What is tested?

What are the reasons for genetic testing?

When you have a family member who knows their genetic change

What are the different types of genetic tests?

Benefits of WGS

Benefits of WES

Benefits of Mitochondrial sequencing

Benefits of target panel testing

Benefits of cascade testing

What are the benefits of genetic testing?

What else should I think about before having a genetic test?

How long does genetic testing take?

What does my genetic test result mean?

How much does genetic testing cost?

Which Australian labs offer genetic testing for mito?

Helpful resources

References

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Genetic testing and mito

Summary

On this page, you'll find:

Prefer to listen?

DNA, genes, chromosomes, and proteins

Genetic testing explained

What is tested?

What are the reasons for genetic testing?

When you have a family member who knows their genetic change

What are the different types of genetic tests?

What are the benefits of genetic testing?

What else should I think about before having a genetic test?

How long does genetic testing take?

What does my genetic test result mean?

How much does genetic testing cost?

Which Australian labs offer genetic testing for mito?

Helpful resources

References

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1. On a scale from 0 to 5 (where 0 is very poor knowledge, and 5 is all the knowledge you feel you need), how would you rate your knowledge?

2. On a scale from 0 to 5 (where 0 is very poor confidence and 5 is all the confidence you feel you need), how would you rate your confidence?

3. On a scale from 0 to 5 (where 0 is very poor wellbeing, and 5 is what you feel your wellbeing should be), how would you rate your wellbeing?

4. On a scale from 0 to 5 (where 0 is very poor access to the services you need, and 5 is you have access to the services you feel you need), how would you rate your access to services: