Testing and Screening for Fragile X
As Fragile X is an inherited genetic condition, if a person finds out they have the premutation or full mutation other family members may also be carriers and/or may have a Fragile X associated condition. There is also a risk of passing the Fragile X premutation or full mutation on to children. A number of reproductive options exist for planning pregnancies and testing.
Reproductive carrier screening
Genetic carrier screening helps people find out whether they have a chance of having a child with a genetic condition, such as Ffragile X syndrome. Genetic carrier screening is available before pregnancy or in the early stages of pregnancy and is becoming increasingly available.
The Fragile X Association of Australia recommends Fragile X carrier testing for:
- People with a family history of Fragile X syndrome or Fragile X-associated disorders, intellectual disability or autism spectrum disorders
- All women considering pregnancy or in the early stages of pregnancy (during the first 12 weeks)
- Any woman with primary ovarian insufficiency or experiencing early menopause.
Preimplantation Genetic Testing
This testing, also referred to as Preimplantation Genetic Diagnosis (PGD), is an IVF treatment and is available to people who know they have an increased risk of having a child with a genetic condition, such as Fragile X. It involves testing embryos for the condition and helps couples avoid having a child with that condition.
Testing during pregnancy
Prenatal diagnostic testing during pregnancy can determine whether a child carries the Fragile X premutation or Fragile X full mutation. Prenatal diagnostic testing procedures include chorionic villus sampling (CVS) and amniocentesis and involve taking a small sample of the placenta or amniotic fluid (fluid around the baby) and performing Fragile X testing. These procedures come with a small risk of miscarriage (~ 1 in 500 for CVS and ~ 1 in 1000 for amniocentesis). Prenatal diagnosis can be arranged through an obstetrician or through a clinical genetics service.
Testing after birth
Testing for Fragile X syndrome is not currently available as part of the newborn bloodspot screening program. If Fragile X syndrome is suspected, testing can be arranged through a general practitioner, paediatrician or clinical genetics service. Testing can be performed on blood or saliva samples.