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Test Identifier Information

Registration CodeCTGN

Karyotyping is no longer offered for the detection of Prader Willi or Angelman syndrome (PWS/AS). Please refer to our testing flow chart.

NB. Microarray testing has replaced karyotyping as the first tier test in paediatric investagations for chromosomal disorder. 

Diagnostic Use / Indications

PWS and AS is detected by a molecular genetic method called Methylation Sensitive HRM PCR.  Please refer to our testing flow chart. A microarray should also be performed as microarray testing detects all currently known microdeletion syndromes in one assay and can also determine the exact region deleted. An array is especially recommended when the diagnosis of PW or AS is not certain, or in very young paediatric cases. Microarray testing will detect ~70% of PWS or AS, ie. all cases caused by chromosome 15 deletion and some cases caused by UPD(15).

FISH testing is useful in the following situations:
1. Family follow-up where the syndrome has been shown previously to be caused by a deletion, to identify other affected relatives or to rule out the rare possibility of a parental balanced rearrangement involving the PWS/AS locus.
2. When the diagnosis is firm and urgency is required.
3. When methylation PCR has confirmed the diagnosis, but microarray testing has not been consented. FISH will only detect 15q11q13 deletion and not UPD(15).
External Price$565.53(Exclusive of GST)

Specimen Collection

Pre-Testing Requirements

It may be useful to discuss this testing with a Clinical Geneticist prior to requesting this test. Phone Genetic Services - toll-free on 0508 364 436.  Alternatively contact the CHLabs Genetic Pathologist by emailing:-

Specific consent is required for microarray testing. Please refer to 'microarray' testing for a link to a form.

Specimen Collection Protocols

 Whole blood is required for genetic testing; please do not centrifuge blood tubes.

Patient Specimen3mL EDTA blood + 1ml Lithium heparin blood
Paediatric Specimen1 mL EDTA blood - Neonates
Sample Delivery to LabRoom temperature. DO NOT refrigerate or freeze

CHLabs Laboratory

DepartmentHaematology - Cytogenetics
Contact Details Email Email
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Contact Phone Number03 364 1425
Test AvailabilityMon - Fri, business hours - urgent testing by arrangement
Turnaround TimeMicrorray: urgent 10 days, non-urgent 28 days, FISH 5 days
Reference Interval

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Uncertainty of Measurement

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Additional Information

 For enquiries regarding this test please email and address to Cytogenetics in the subject line

Delphic Number Test Number5445

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