Expanded Carrier Screening

Some genetic conditions follow what is known as autosomal recessive inheritance. For a child to be born with an autosomal recessive condition, they need to have inherited one faulty copy of a gene from each parent. As all of our genes come in pairs, a person who has one faulty copy and one working copy of a gene for a recessive condition is called a carrier. That is, they carry the altered copy of the gene, however usually the display no symptoms of this condition. All of us are carriers for multiple different autosomal recessive conditions. When we have children, if we are not related to our partner (for example, cousins) the chance that both parents will be a carrier of the same condition is low.

However, when a child is born with an autosomal recessive condition, they are usually the first person in their family to have this condition. Various guidelines recommend that women be offered carrier screening. This is an option available to couples, either before their first pregnancy or before embarking on another pregnancy.

The Invitae Carrier Screening test is Insight Genomica’s first choice for expanded carrier screening. The full version of the test screening for 287 different genetic conditions, but most importantly it includes Cystic Fibrosis, Fragile X and Spinal Muscular Atrophy. More information about this test can be found at Invitae Carrier testing (https://www.invitae.com/en/physician/category/CAT000239/ )

Insight Genomica’s other choice for expanded carrier screening is the Counsyl Foresight carrier panel. This test analyses over 170 different genetic conditions. More information about this test can be found at https://www.counsyl.com/services/foresight/

If a couple is found to both be carriers of the same condition, they will have a 1 in 4 or 25% chance of having an affected child. They couple would then have the choice of utilizing IVF techniques or other prenatal testing options to either test for an affected pregnancy or ensure having an unaffected pregnancy.

Scientific references

Prenatal screening and diagnosis of chromosomal and genetic abnormalities in the fetus in pregnancy (http://www.hgsa.org.au/documents/item/6110)