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Beacon expanded reproductive carrier screen

Also known as: Extended carrier screen, preconception screen

Test category:

Reproductive - Carrier screen

Use of test

Purpose:

This is a screen to identify carriers of >350 autosomal recessive mutations and (for female patients) >50 X-linked recessive mutations which cause serious childhood-onset disorders. Approximately 70% of Australian individuals are identified as carriers for one or more disorders using this investigation. Most carriers do not have a family history of relatives affected by the disorder and are unaware that they are carriers. Approximately 1 in 20 Australian couples will be found to have a one in four chance of having a child with one of these disorders.

Utility:

The result provided will indicate whether a mutation was found, and the implication for the patient. If both partners of a couple are carriers of mutations in the same genes, there is a one in four chance of them having a child with that disorder. If the female partner is found to be a carrier of an X-linked recessive disorder, there would be one in two chance of their child i.e. a one in two for their son, having the disorder.

It is important to note that no preconception carrier screen is able to detect every mutation that might cause a genetic condition included in this screen. Therefore, a 'no mutation' result does not eliminate the risk to the patient of having a child affected with a genetic disorder.

Our clinical and scientific experts have selected the most common mutations and best technology available to detect the vast majority the relevant mutations for these inherited conditions.

Depending on the results provided, referral for genetic counselling and discussion of reproductive options may be appropriate. A list of private and public providers of clinical genetics and genetic counselling services is available here. For couples who are identified as having a high chance (one in four, or 25%) of having an affected child, Sonic Genetics offers free genetic counselling.

Ethical considerations:

This is an assay for heritable mutations. It may raise issues of ethics or consent that are different from most other investigations ordered in the routine care of a patient. The consent form is not mandated, but could be used to guide the discussion with the patient.

In the case of carrier testing of an unaffected child, national regulations require that the laboratory has evidence of pre-test counselling by a genetics professional and written consent.

Methodology:

Sonic Healthcare genetics laboratory in Sydney, Douglass Hanly Moir Pathology, sends the sample to Fulgent Genetics in California for analysis. The coding region of each gene is sequenced and examined for pathogenic mutations and deletions. This analysis detects >98% of documented mutations in these genes. The Fulgent Genetics laboratory is accredited. Click here to visit the Fulgent website.

Requesting the Test

Ordering:

This test can be requested by any medical practitioner.

You can order Beacon through Genie, Best Practice and Medical Director.

Request form:

Download the expanded carrier screen request form.

Sample required:

4 mL blood in EDTA (separate tube required). Specimens may be collected by the requesting practitioner or at any Sonic Healthcare collection centre (see link below).

To help ensure the quality of the test, a genetic test should be done with a dedicated sample whenever possible i.e. a sample collected specifically for that test rather than a sample that is used for multiple tests.

We recommend that the patient or another adult check the labelling of request forms and sample tubes. 

>Link to Sonic Healthcare collection centres

Special instructions:

Please note whether or not the patient has a family history of a single-gene disorder on the referral form. If there is a family history, please provide as much information as possible about the family pedigree and any previous testing with results (if available). If the partner is being tested at the same time, please ensure their details are noted on the request form and vice versa.

Turnaround time:

5 weeks.

Price:

$595.

Rebate:

This test is not rebated by Medicare. The laboratory assumes that the patient or client has provided informed financial consent for the test.