A genomic sequencing test examines hundreds of genes in your genome to identify changes that may affect you.

Genomic sequencing is widely known for its use to track the spread of COVID-19. But it has many more benefits for our health.

What is genomic sequencing used for?

Genomic tests can be used to diagnose a wide range of conditions that have a genetic origin.

Melbourne Genomics studies compared genomic testing to other types of tests for patients with certain types of cancer, kidney disorders, neurological disorders, rare genetic conditions and congenital deafness.

On average, individuals with those conditions who received genomic tests were 9 times more likely to get an informative result than those who didn’t. More than half of those who got a result had a change in care because of it. Here are the topline results.

Genomic sequencing is also critical in the fight against viruses like COVID-19 and antibiotic-resistant bacteria. By sequencing a virus or bacteria’s genome, we can determine which type is spreading and how it may have spread.

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How does a genomic test work?

The test aims to find changes (called variants) in your genes that can affect your health.

It starts by taking a DNA sample, usually a blood, saliva or tissue sample. The DNA is analysed by computer programs and ‘written out’ as a letter code, which is unique to each person. Once that happens, experts can look at large sections of the code to see if any of your genes appear different to what is expected.

If variants of interest are found, they are further examined to see if a particular variant can explain your specific health condition. This requires a team of experts who look at your medical history, your family history and what we know about the genetic causes of your condition.

Here is a step-by-step explanation of a genomic test.

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What is the difference between a genetic test and a genomic test?

Genetic tests look at one or a few genes at a time. Genomic tests can look at hundreds or thousands of genes at a time, yielding much more information that can be used to inform care.

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How is genomic sequencing used to control COVID-19 and superbugs?

Like people, every germ has a unique genetic ‘fingerprint’. Genomic sequencing identifies that fingerprint. As viruses and bacteria reproduce by copying themselves, if the exact same copy is detected across multiple people, they probably contracted it from the same source.

Sequencing enables experts to determine from whom and where a particular infection is spreading, and then take appropriate measures to stop transmission, such as quarantining or cleaning specific areas. This can stop a widespread outbreak from occurring.

Learn more about genomic testing process for superbugs.

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How can genomic testing be used for cancer treatment?

Genomic testing can be used for many types of cancer. Sequencing the DNA in cancer cells can find the genetic changes that drive tumour growth, and may point to treatments that are known to work for certain gene changes. However, this is not helpful for all cancers and it is possible that gene changes are found but no treatments are available for that gene change. Talk to your oncologist about whether genomic testing may be helpful for you.

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What kinds of genomic tests are available?

There are about 23,000 genes in the human genome. There are different types of genomic tests, depending on the number of genes to be examined.

Gene panel tests look for changes in a specific list of genes. For example, a comprehensive cancer panel may include 300-400 different genes. 

Exome tests sequences a person’s exome and looks at genes associated with the patient’s condition. An exome is only 1-2% of your entire genome, but it includes all protein-coding genes. Most genetic disorders are caused by mutations in these genes. 

Genome tests sequences the whole DNA sequence of a person or organism, including the coding and non-coding regions. Usually when genome sequencing is done, only genes associated with the patient’s condition are looked at.

What is a trio test in genomics?

A trio exome or genome test looks at the genes in an individual and usually both their biological parents – or other relatives – at the same time. Trio tests often provide answers more quickly, as experts are able to easily determine if variants are new or inherited by comparing results.

What are additional findings in a genomic test?

Testing for ‘additional’ findings means deliberately analysing the genome for gene changes that are known to be associated with future risk of preventable or treatable conditions unrelated to the patient’s current medical condition. Additional findings are also known as ‘secondary findings’ as they are not related to the (primary) reason for conducting the genomic sequencing test. 

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How long does a genomic test take?

Because of the size of a human genome, the complex analysis needed, and the multidisciplinary team required, a genomic test can take up to nine months to provide a result. 

But with established testing pathways and dedicated analysis tools, Melbourne Genomics proved that tests could be processed in under three weeks when urgent results are needed for acutely unwell children. 

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How can I get a genomic test?

Discuss getting a genomic test with your doctor. They may refer you to another specialist or genetic service. 

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Should I get a genomic test online?

If you are trying to find the cause of a health issue, the most appropriate way of accessing a genomic test is through your doctor.

Some direct-to-consumer companies can provide genomic screening to identify ancestry and family history. The tests they offer are different to clinical genomic sequencing tests. 

If you intend to have a test online, you should also check out how the company will manage and protect your genomic data. The Genioz study has very helpful resources on online genomic testing.

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What can a genomic test tell you about me?

Humans have around 20,000 protein-coding genes and we are still discovering them and learning what they do. A genomic test looks at a specific list of genes that we know may relate to a particular health condition. Only those genes are analysed in the test.

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Melbourne Genomics acknowledges the Wurundjeri people of the Kulin Nation, on whose lands we work, and all First Nations peoples across Victoria. We pay respect to Elders past and present. We also acknowledge the First Nations health professionals, researchers and leaders who are shaping the future of genomic medicine.

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