Genetic and Genomics Testing

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 vs genomic testing – what’s the difference?

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 

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 

Panel testing enables multiple genes associated with a known condition, such as intellectual disability or epilepsy, to be screened at the same time. 

Exome sequencing 

This test enables the protein-coding areas in genes – called exonsto 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 

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. 

Trio genomic tests 

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’. 

Microarray testing

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.

Genomic testing

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.
You can not see them

 

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

Doctors can

· look at  1  gene

· look at a group of genes

 

Some times the parents get tests too.
 

 

The doctors may find a changed gene.

 

 

 This gene is why your child· is sick

  or

· has a disability

 

This is good. You have an anwer. It is a diagnosis.

 

 

Or

The doctors can not find a changed gene.
Or

 

The doctors find a problem gene.

 

But

It is a new changed gene.
The doctors

· have not seen this gene before

· do not know what it means.

Does this gene make your child· sick?

  or

· cause their disability?

There is no name for it.
You may· feel sad

· worry

· scared.

You may· feel you are alone· not know how you feel.

 

  But

You may also feel happy.

More information
SWAN can help.

Call     0404  280  441
Email     [email protected]
Website     www.swanaus.org.au
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