Genetic Tests

Lab	Department of Molecular Genetics The Children's Hospital at Westmead NSW
Test Name	X-inactivation
Genes tested	AR FMR1
Test Description	X-inactivation studies are offered for X-linked disorders and for chromosomal variants involving the X chromosome. Testing is used as a supplement to clinical information and other testing. X-inactivation studies cannot be used as a sole diagnostic tool due to the low specificity of the assay. Cost $200 (proband)
Method Type	specific assay/s
Method Comment	Restriction digest with methylation sensitive enzymes followed by quantitative microsatellite analysis. A highly polymorphic microsatellite located in the AR gene is the primary assay. The CGG repeat in the FMR1 gene can also be used but consent to test this gene must be obtained as it may reveal an unrelated full mutation or premutation in the FMR1 gene.
Sample Required	Testing should be performed on a tissue considered relevant to the possible skewing of X-inactivation. 5 mL blood in EDTA or 5 micrograms of DNA RCPA guideline re sample requirements
Turn around	2 months

The following information is provided and updated from time to time by laboratories providing genetic testing. The list of laboratories is not an exhaustive list of the laboratories that provide such testing. Links to a third party website are provided for convenience only. The Royal College of Pathologists of Australasia (RCPA) accepts no responsibility for, and makes no representation concerning, the accuracy, appropriateness, and completeness of the information contained on the following pages or on any linked websites. The RCPA does not provide any direct or implied endorsement of the tests or laboratories listed, and accepts no responsibility for the information provided. The RCPA recommends that all medical testing be performed in an accredited laboratory, and emphasises that the listing of a test or laboratory on this page does not imply that it has been accredited by NATA/RCPA or any other organisation. Users of this information should seek expert professional advice before making any decisions based on this information. Please note that charges may apply for gene tests; enquiries about charges should be made to the laboratory to which a sample is to be referred prior to referral. Users access the linked websites at their own risk.

The Rotal College of Pathologists of Australia