Providing information and support to families caring for a child with an undiagnosed or rare genetic condition.
You can learn more about genetic and genomic testing in our Genetic and genomic information sheet or our Easy English – What is a gene test information sheet. We also have a range of videos on genetic and genomic testing.
Genetic testing examines one single gene or a group of genes to check for variations that may cause a particular condition.
Genomic testing, on the other hand, can study every gene, providing a complete picture of a person’s genome (their genetic map).
Single gene testing is performed if a person has a pattern of features symptomatic of a condition that is linked to a single gene. This test is also useful if there is a family history of a particular condition.
Panel testing enables multiple genes associated with a known condition, such as intellectual disability or epilepsy, to be screened at the same time.
This test enables the protein-coding areas in genes – called exons – to be screened simultaneously. The exome represents about 1% to 2% of a person’s genome but is where more than 90 per cent of gene changes that cause health conditions occur.
Genome sequencing provides the most comprehensive picture of a person’s genome. This test can pick up gene variations exome sequencing can’t by reading the entire genetic code to look for gene changes. It has a diagnosis success rate of up to 50%, depending on the patient’s observable characteristics.
In most cases, only the person with the medical condition is tested. Sometimes samples may also be taken from family members to simplify analysis. Screening DNA from a child and both parents is called a ‘trio genomic test’.
Access to genomic testing is still limited in Australia. This is despite the approval in May 2020 of additional Medicare item numbers for whole exome or genome sequencing to identify the genetic cause of childhood syndromes. To qualify for the test, a child must meet certain criteria. They must be aged under 10 years and have dysmorphic features and a moderate or severe intellectual disability highly indicative of a monogenic condition. The Medicare item numbers also cover reanalysing data under certain circumstances and cascade testing to diagnose biological siblings or inform reproductive decisions.
Genomic tests can be requested by a clinical geneticist or a specialist paediatrician (following consultation with a clinical geneticist). At this point, there are very few specialist paediatricians ordering genomic tests.
What is a gene test
|Everyone has many genes.
They are in our body.
Some genes can
· make your child sick
· mean your child has a disability.
Doctors may test your childs genes.
It can help doctors know why.
It can help parents know why
|The doctor may take
· some blood from your childs arm
· saliva from your childs mouth
· look at 1 gene
· look at a group of genes
|Some times the parents get tests too.|
|Call 0404 280 441|
Microarray testing is used to detect missing or duplicated segments of DNA.
These changes are too small to be detected under the microscope. Microarray testing works by comparing a patient’s DNA with a reference DNA sample and identifying any variations. A microarray test has a 10% to 15% diagnosis rate.