Diagnosis & Screening for Fragile X

The Fragile X Association of Australia represents families and carers of people with Fragile X-associated Disorders (FXDs): Fragile X syndrome (FXS), Fragile X-associated Premature Ovarian Insufficiency (FXPOI) and Fragile X-associated Tremor Ataxia Syndrome (FXTAS). Information on this website contain more detailed information on these disorders. 

 

One of the key issues in the management of FXDs is appropriate and timely diagnosis and screening. This statement presents the FXAA’s position on diagnosis and screening.

*****************************************************************

                             Diagnosis and Screening for

Fragile X syndrome (FXS) and Fragile X (FX) carrier status

June 2015

The Fragile X Association of Australia (FXAA) strongly recommends:

(1)    diagnostic testing for children and adults with developmental delay and other indicators for the detection of FXS, in order to detect any FX association and to offer appropriate treatment and management strategies;

(2)    diagnostic testing of embryos of women who have FX carrier or FXS status and of any women who request it;

(3)    screening for FXS or FX carrier status in all women prior to or in early pregnancy, in order to provide the widest range of family planning options; and

(4)    introduction in the future of screening of all newborn babies for FXS (newborn bloodspot screening) which is currently not available.

Some expanded information follows but it is strongly recommended that anyone interested in being tested discuss available options with their doctor or a genetic counsellor.

Various options exist and need to be accessed through a GP, paediatrician, obstetrician or any medical practitioner or genetic counsellor

1) Diagnostic testing for males and females with a clinical reason for testing including autism spectrum disorder, intellectual disability, developmental delay of unknown cause, fertility problems, tremor/ataxia of unknown cause or family history of Fragile X-associated Disorders.

This is a relatively routine test that can be requested through most major pathology providers.  There is a Medicare rebate for this test if the patient exhibits any Fragile X-associated Disorder 1 symptoms or if Fragile X syndrome has been diagnosed in the family. However, there may be some out of pocket costs.

 (2) Diagnostic testing of embryos

Pregnant women with FXS or who have FX carrier status can have a test of their foetus at 11 weeks with a result available in 3 weeks.  They can then make a decision about their pregnancy based on the results of the test and in discussion with a genetic counsellor.

Another option is to use IVF and Pre-implantation Genetic Diagnosis (PGD) to ensure that non-FX embryos are used.

(3) Screening for women and men

Screening for FXS or FX carrier status can be undertaken prior to pregnancy or early in pregnancy, and gives people information about their risk of having a child with FXS. People who have a relative with FXS or another Fragile X-associated Disorder have a higher risk of being a carrier of FX than most people.

Carrier screening is also relevant for people who do not have a family history of FX because many people who are carriers of FX do not have anybody in their family who has FXS or another FX-associated Disorder. It is estimated that 1 in 170 women and 1 in 800 men are carriers of FX.

Women who have FX carrier status are at risk of having a child with FXS. Men who have FX carrier status do not have FXS children but pass the carrier status on to all their daughters.

_____________________________

[1] Fragile X-associated Disorders include Fragile X syndrome (developmental or intellectual disability), FXTAS (Fragile X-associated Tremor Ataxia Syndrome) and FXPOI (Fragile X-associated Premature Ovarian Insufficiency).

If a woman learns that she is a FX carrier, Fragile X Association of Australia suggests arranging an appointment to see a genetic counsellor. A genetic counsellor will take a detailed family history, discuss the results, options for further testing if she is pregnant, options such as pre-implantation genetic diagnosis through IVF for future pregnancies, and can help with making decisions and providing support. The genetic counsellor can also discuss genetic testing for other relatives who may also be carriers.

FX carrier screening by DNA testing can be ordered by any medical doctor or through a clinical genetics service. The process involves a simple blood test or, in some cases, a cheek swab. The cost is covered by Medicare for people with a family history of FX-associated Disorders. For those without a family history, there is a charge (usually around $150-$200). Some services also offer carrier screening for other common inherited conditions alongside FX carrier testing. If you are interested in this it is worth discussing these options with a genetic counsellor, obstetrician or your GP.

Details of genetics services around Australia can be found here: http://www.genetics.edu.au/Genetics-Services/genetic-counselling-services

(4) Newborn bloodspot screening for FXS 

Newborn screening for FXS is currently not available in any state or territory of Australia. A national Newborn Bloodspot Screening Working Group was established in 2014 and is expected to report in 2016. It is hoped that the criteria for testing will ensure the inclusion of conditions such as FXS where early intervention and treatment make a difference to the life of the individual, their family and society. (Note that newborn bloodspot screening for FX carrier status is not recommended by current medical ethical guidelines.)

The demonstrable benefits of early treatment and behavioural intervention, in addition to the identification of risk in subsequent and relatives’ pregnancies, present a strong argument in favour of FXS newborn population screening. As both the degree of intellectual disability and behavioural problems are highly variable (especially in females with FXS), the average age at clinical diagnosis is significantly delayed in Australia (at around 5 years). Newborn bloodspot screening would remove this delay.

__________________________________________________________________________

If you have any queries about diagnosis and screening for Fragile X syndrome and Fragile X carrier status please contact the Fragile X Association of Australia on 1300 394 636 (free call) or by email to:  support@fragilex.org.au

This entry was posted in Uncategorized. Bookmark the permalink.

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>