Genetic Services of WA – referral guidelines for clinicians

There are several common referrals received by Genetic Services of Western Australia (GSWA) that require test results to be attached for triaging purposes.

Cancer (familial cancer syndromes)

A referral to our familial cancer program needs to include the types of cancer diagnosed in the family, the ages of diagnosis and whether genetic testing has been carried out in a family member.

Please see our Familial Cancer Program Referral form (PDF 1MB) for further details.

Genetic Paediatric Service

Please see our Genetic Paediatric Service referral form (PDF 101KB) (Word 56KB) for further details.

Cardiac conditions (long QT, CPVT, Brugada Syndrome)

A copy of the relevant investigations and confirmation of the patient’s diagnosis is essential. A brief outline of the relevant family history is also appreciated.

Chromosome abnormalities

If your patient has been found to have an abnormal chromosome result, please attach this result to the referral.

Cystic fibrosis

GSWA protocol is not to see couples unless both partners are carriers of a mutation in the CFTR gene. However, if your patient is already pregnant, we will see the couple as a matter of urgency to expedite testing. Cystic fibrosis carrier testing has a 30 day turnaround time.

To determine whether one or both is a carrier, please request 5-10ml EDTA from the relevant partner/s be sent to PathWest QEII Diagnostic Genomics laboratory for carrier testing.

Please include relevant family history if a family member has been found to be a carrier of a mutation. Please include:

  • the name and date of birth of the affected/carrier member of the family and their relationship to the person being tested
  • the particular mutation which has been found in the family (if possible). This will allow the laboratory to screen for the family mutation along with other common CF mutations.

If both partners are found to be carriers of CF, please refer them, with test results, to GSWA for counselling and information regarding options for prenatal diagnosis.

If one partner is a carrier of a CF mutation, but the other partner is not, the risk of an affected child is less than 1:500. Prenatal diagnosis is not indicated where only one partner is shown to be a carrier of CF. However it is important that children of a carrier parent are offered carrier testing when they are young adults.

If neither partner is found to be a carrier of a CF mutation, the risk of an affected child is very low. It is not possible to screen for all the known CF mutations.

A GSWA genetic counsellor is available to discuss any questions you may have regarding CF testing on 6458 1525.

Deafness and hearing loss

There are strict criteria around referrals for hearing loss. An appointment with GSWA will only be offered where the hearing loss:

  • is congenital, that is diagnosed at the initial newborn screen or in the first 2 years of life

and

  • affects both ears

and

  • is severe to profound (though this may not have been established in infants).

Alternatively an appointment may be offered if:

  • there is a family history
  • the hearing loss is thought to be part of a syndrome
  • the child has some unusual features (dysmorphism)
  • there are other musculoskeletal factors
  • imaging has been performed and has shown specific structural anomalies.

This is not a comprehensive list but it aims to exclude patients with mild to moderate levels of isolated deafness.

Clinical situation permitting, please ensure an MRI or CT scan has been performed and the report is included with the referral.

First and second trimester screening – increased risk results

We do not routinely accept referrals for increased risk on prenatal screening tests. Referrals will be accepted on a case by case basis only . To ensure your patient is seen as soon as possible the following must be attached:

  • the first or second trimester screen result
  • the laboratory copy of the patient’s blood group
  • copies of early pregnancy tests including tests for HIV, hepatitis and other infections.

Please ensure you have discussed the increased risk result and referral to GSWA with your patient prior to referral.

Haemoglobinopathy

Being a carrier for a haemoglobinopathy is common and its main importance concerns issues related to reproductive options and antenatal diagnosis. 

Therefore, it is GSWA protocol to only see couples who are both known carriers. Therefore please arrange the following for your patient and their partner:

  • full blood picture
  • haemoglobin HPLC
  • blood for haemoglobinopathy DNA testing

The sample should be taken 4ml in EDTA and it is important to note the ethnicity of both your patient and their partner on the request form.

It is prefer that these tests are performed by PathWest, which is the WA haemoglobinopathy reference laboratory.

If the patient and the partner are both shown to be carriers of a haemoglobinopathy, GSWA will be happy to see the couple to discuss the matter further, including options for future prenatal diagnosis if appropriate.

Any referral should be accompanied by copies of both partners’ results.

If the woman is pregnant, we are happy to accept a referral immediately and will expedite testing for the relevant partner, arrange an appointment to discuss the results and, if necessary, arrange prenatal diagnosis as a matter of urgency.

Marfan Syndrome

In view of the complexity of the molecular genetic analysis of the fibrillin gene, patients are initially screened according to the modified Ghent criteria as to their suitability for mutation analysis.

Before clinical review, the following examinations are needed to facilitate the formal diagnosis of this condition:

  • examination of the heart and ascending aorta via echocardiogram
  • examination of the eyes by an ophthalmologist.

Additionally and importantly, this approach will help to avoid delayed diagnosis of treatable complications of this disorder.

Therefore, before referring your patient please arrange the above investigations.

MTHFR gene polymorphisms and neural tube defects

GSWA does not see patients referred due to polymorphisms in the MTHFR gene. Testing for Methylenetetrahydrofolate reductase (MTHFR) is not clinically useful in the setting of recurrent miscarriages or neural tube defects (NTDs) because it is only one gene in the complicated folate metabolism pathway.

Having one of the polymorphisms would not change patient management – having a polymorphism is not the cause of neural tube defects or miscarriage as otherwise 60 per cent of the population would have recurrent NTDs and miscarriages.

Having an MTHFR polymorphism does not inform you about the risk for recurrent NTDs. Either with or without the polymorphisms, a woman who has had more than one NTD affected pregnancy should be on a high dose of folate.

Multiple miscarriages

As there can be many different reasons for multiple pregnancy loss we do not see patients for this reason unless an underlying genetic cause, such as a chromosomal abnormality, has been confirmed.

Large chromosomal abnormalities that can cause recurrent miscarriage can be detected by a karyotype. A GP is able to arrange this (for both the male and female partner) and it involves a simple blood test. If a chromosomal difference is identified then referral to GSWA is welcome.

If both partners show no chromosomal abnormalities then a referral to a fertility specialist or obstetrician may be useful in elucidating the mechanism behind the multiple pregnancy loss.

Paternity testing

Please be aware that GSWA does not currently carry out paternity testing. Please refer patients to a private laboratory.

Teratogen exposure in pregnancy

We do not see patients for exposure to known teratogens (drug category D or X) during pregnancy.

King Edward Memorial Hospital operates an Obstetric Drug Information Service which can be contacted for expert information on drug exposure in pregnancy. Phone 6458 2723 between 8.30am – 5.00pm, Monday to Friday.

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Genetic Services of WA