In this section
Laboratory Services has an established process for review and referral of high-cost genetic test requests for RCH patients. The process ensures patients have access to high quality genetic tests which are likely to yield a diagnosis and answer the clinical question
posed by the treating team.
A multidisciplinary meeting is held each month, attended by the laboratory-based Genetic Counsellor, geneticists, Laboratory Director and Specimen Reception Manager and subspecialists. Clinicians seeking genetic testing for patients are welcome to attend. Communication to clinicians
relating to test requests which are changed or declined is communicated via email or Staff in-box message in EPIC.
Subject to available budget to cover test costs, the review process supports testing in the following circumstances;
The Medical Benefits Schedule (MBS) provides reimbursement for a small number of genetic tests for eligible out-patients (private patients, or those attending MBS clinics), but not for hospital in-patients. Examples include whole exome sequencing for childhood
syndromes for eligible children aged 10 years or younger (MBS Items 73358, 73359, 73360), genetic testing in suspected Alport syndrome (MBS Item 73298) and in familial hypercholesterolaemia (MBS Item 73352 and 73353). See below for more details on how to order an MBS funded exome.
Genetic tests are requested as pathology orders in EPIC.
Given the large numbers of genes in the human genome, and the subsequent high number of genetic testing options, it is not possible to have a specific order name for every genetic test. A number of commonly ordered specific gene or syndrome tests are available as well as
The table shows frequently ordered examples;
Used for single genes or gene panels.
The disorder, gene list or gene panel can be specified in the order
Used for ordering genetic tests for specific genes or panels associated with immunology genetic disorders
such as those associated with autoinflammatory or periodic fever, TRAPS, Familial Mediterranean
Fever, Primary immunodeficiencies, Haemophagocytic Lymphohistiocytosis, etc.
Dr Stephanie Richards)
RCH paediatricians are able to order Medicare-funded whole exome sequencing for eligible patients with certain phenotypes. For other patients who may benefit from whole exome sequencing, referral for a clinical genetics consultation should occur, as some funding options for testing remain
restricted to tests ordered by the clinical genetics team.
For exome sequencing tests, RCH paediatricians and specialists are expected to have undertaken online learning by completing the Learning Hero Genomics
Yana Smagarinsky BScBA MGenCouns
Yana is the laboratory-based genetic counsellor and is available for advice and support.
The lab-GC reviews and triages genetic and genomic test requests and liaises with clinicians to obtain further details to ensure that the requested test is the most appropriate test and is likely yield the required information. The lab-GC is supported by a clinical geneticist
and a range of subspecialists with genomic knowledge.
The lab-GC assists in the selection of the most appropriate testing laboratory based on the following principles;
Services gratefully acknowledges the RCH Foundation in supporting Yana’s role.
A/Prof Sue White MBBS, FRACP
A/Prof White is the clinical geneticist providing support to the lab-GC and guiding the selection of tests and referral laboratories.
Laboratory Services gratefully acknowledges the support of the following subspecialists with genomic expertise who assist in the review process;
Professor Monique Ryan (Neurological disorders), Professor John Christodoulou (Biochemical genetics and metabolic disorders), Dr Heidi Peters (Metabolic disorders), Dr Sharon Choo (Immunological disorders), Dr Michele O’Connell (Endocrine disorders), and Dr
Katherine Howell (genetic epilepsies).
Once a test request has been approved and a referral laboratory selected, the Lab Services specimen reception team managed by Mr Paul Marcus (email@example.com) are responsible for transport of specimens to a range of local, interstate and international laboratories as well as receipt of results.
Testing is most commonly performed on DNA extracted from peripheral blood, although saliva, skin fibroblasts and tumour tissues are sometimes used
If the patient has previously had a microarray test performed at VCGS, it is likely that stored DNA can be used for testing and no additional pathology collection is required.
Obtaining informed consent for complex genetic tests (such as multi gene panel testing, exome and genome sequencing) is especially important because of potential implications for other family members, reproductive risks and future well-being (for example for subsequent
children, or the ability to obtain insurance). There are limitations to genetic testing that need to be understood. In many cases, not all genes that predispose to a certain condition are known, so a negative result does not necessarily mean that an individual does not have a
genetic cause for their condition. Genomic testing may result in identification of variants of uncertain significance that can be difficult to interpret, the implications of which should be clearly understood by families prior to agreeing to the testing. Genomic testing may identify variants associated with diseases
that are not related to the indication for testing.
A genetic test is best used to answer a specific clinical question
Genetic tests are generally poor at “ruling things out” (so it is best not to use as a test of exclusion) for a variety of reasons:
Consider how sure are you that the child’s presentation is due to a gene change that this test can identify.
If you are seeing a patient who is (or may be) undergoing genetic testing, hold off on other investigations where possible (for example in a stable outpatient) until genetic testing is completed.
Consider the most likely fit for child’s phenotype and order the most appropriate test. Concurrent or sequential testing is not good clinical practice, the lab-GC is available to assist in test selection.
Predictive testing – testing of unaffected, at-risk relatives for a pathogenic variant known to cause disease
Segregation testing – testing of biological relatives for a variant of unknown significance with the aim of clarifying the pathogenicity (usually at the request of the testing laboratory or clinical geneticist)
Cascade testing – genetic testing of healthy biological relatives for a known pathogenic variant in order to avoid/inform of risk of disease
Panel testing – where there is a clinical suspicion of a condition which can be caused by a number of genes. Eg. Cardiomyopathy panel, RASopathy panel, arrhythmia panel
Proband – the first person in a family to receive genetic counselling and/or testing for suspected hereditary risk. This person is usually (but not always) affected with the disease in question.
Trio testing – genomic testing of a proband in conjunction with their biological parents. This can be particularly useful where there is consanguinity or where the family is from an ethnic minority.
Click here for detailed information on how to order MBS funded Whole Exome Sequencing (attachment)
Click here to see an expanded version of the EPIC smart phrase ".exome" (attachment)