Pre-pregnancy Carrier Screening

The Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG) recommends that information about reproductive carrier screening for common disorders be offered to all women planning a pregnancy (pre-conception) or in the first trimester of pregnancy.

What is carrier screening?

Carrier screening is performed as a blood test to determine if you are a carrier of one or more autosomal recessive or X linked genetic conditions.

Autosomal recessive conditions require a “double dose” for a person to be affected with the condition. A carrier “single dose” will be unaffected i.e. will not have the condition. For a fetus to be affected by a recessive condition, they must inherit one abnormal chromosome from each parent. If the woman tests positive, her partner will then need to be tested too.

X-linked conditions will be silent in the carrier female. Normal female chromosomes are XX. A carrier will have one X chromosome affected and one normal so she will not manifest the condition. The other X chromosome “masks” the condition. Normal male chromosomes are XY. If the single X chromosome is affected, the male will manifest the condition.

If a carrier mother has a male fetus, there will be a 50% chance of him inheriting her affected X chromosome. As males have only one X chromosome the condition will be manifest in the child. If the male fetus inherits her normal X chromosome, he will not have the condition.

If the carrier mother has a female fetus, 50% will be a carrier like the mother. The other 50% will not carry the condition.

What conditions are screened for?

WUMe offers the Horizon 4 Carrier Screen test for four conditions that have a high carrier rates in a normal population. These are:

• Cystic Fibrosis (CF)
• Spinal Muscular Atrophy (SMA)
• Fragile X syndrome
• Duchenne Muscular Dystrophy (DMD)

Further screening options are Horizon 27, Horizon 106, Horizon 274 which can screen for up to 274 recessive and X-linked genetic conditions.

Click for FULL HORIZON CONDITIONS LIST

What is the cost of Horizon Advanced Carrier Screen test?

For more information, please visit Horizon Carrier Screen Test