What is Edwards syndrome or trisomy 18?

What is Edwards syndrome?

Edwards syndrome is a chromosomal condition. It happens when a baby’s cells have 3 copies of chromosome 18, rather than the usual 2.

The extra chromosome 18 causes severe intellectual disability and physical anomalies.

Babies born with Edwards syndrome often have:

low birth weight
a small head and jaw
low-set ears
clenched hands
anomalies in the heart, lungs, diaphragm, blood vessels, gut, bones and kidneys
difficulty seeing, hearing and feeding.

Most babies born with Edwards syndrome don’t live beyond the first weeks of life. A few survive their first year and beyond.

Sometimes only some of a child’s cells have an extra copy of chromosome 18. This is called mosaic Edwards syndrome. Children with mosaic Edwards syndrome can have a milder form of the condition.

Edwards syndrome is also called trisomy 18.

For typical human development, we need 46 chromosomes in all of the cells in our bodies. Chromosomal anomalies are when there are missing or extra chromosomes or changes in the structure or arrangement of the chromosomes.

Diagnosis of Edwards syndrome

You can have tests during pregnancy to help you find out whether your baby has Edwards syndrome.

Your midwife or doctor can give you more information about these tests.

Edwards syndrome can also be diagnosed at birth because there are key physical features that your doctor can see. If the doctor thinks your baby has Edwards syndrome, the doctor will confirm this by giving your baby a blood test.

If you’re told that your unborn or new baby has Edwards syndrome, it can be a big shock for you and your family. Talking with other parents can be a great way to get support. You can connect with other parents in similar situations by joining a face-to-face or online support group. You can also get support from organisations like Genetic Alliance Australia.

Support and treatment for children with Edwards syndrome

There’s no cure for Edwards syndrome.

If you’re told that your unborn baby has a chromosomal condition like trisomy 18, your midwife, GP or obstetrician or a genetic counsellor will be able to give you information and support. This can help you decide what’s best for you and your family during pregnancy.

When babies are born with Edwards syndrome, there are often very sad and difficult decisions and choices to be made. This might include a choice between making a baby comfortable and prolonging life through invasive surgery.

Some children with mosaic Edwards syndrome live to adulthood. If your child has mosaic Edwards syndrome, early intervention is the best way to support your child’s development. Early intervention includes therapies, education and other supports that will help your child reach their full potential.

If your baby is diagnosed with Edwards syndrome before or after birth, the following professionals might be able to help you:

The National Disability Insurance Scheme (NDIS) might support your child with Edwards syndrome, as well as you and your family. Our guide has answers to your questions about the NDIS.

What causes Edwards syndrome?

Edwards syndrome is most often caused by a random genetic change during the formation of a parent’s eggs or sperm.

Less often, this change occurs after conception, while the baby is still developing in the womb.

If women are older when they get pregnant, they have a higher chance of having a baby with Edwards syndrome.

If you have one baby with Edwards syndrome, your chance of having another baby with the syndrome is usually very low. Genetic testing can give you more information about this.