Trisomy 18

What is Edwards syndrome?

Edwards syndrome is a genetic condition that causes serious health problems and disabilities. It’s caused by an extra copy of chromosome 18.

Edwards syndrome is very rare. About 1 in 5000 babies has Edwards syndrome.

Sadly, most babies with this condition die before or soon after birth.

What are the symptoms of Edwards syndrome?

Babies with Edwards syndrome may have:

• problems gaining weight and growing
• low muscle tone
• an unusual-looking face and head
• learning disabilities
• unusual hands and feet with overlapping fingers and webbed toes
• heart problems
• kidney problems

What causes Edwards syndrome?

Children with Edwards syndrome have 3 copies of part or all of chromosome 18. This is why it’s also called trisomy 18. People who don’t have this condition have 2 copies of chromosome 18.

It is usually caused by a change in the egg or sperm before the baby is conceived.

Types of Edwards syndrome

Full Edwards syndrome — is when your baby has an extra copy of chromosome 18 in all their cells.

Mosaic Edwards syndrome — is when your baby has an extra copy of chromosome 18 in some of their cells.

Other trisomy conditions

Other conditions caused by trisomy are:

• Down syndrome — 3 copies of chromosome 21
• Patau’s syndrome — 3 copies of chromosome 13

How is Edwards syndrome diagnosed?

Edwards syndrome can be suspected or even diagnosed during pregnancy.

Sometimes the possibility of Edwards syndrome is raised at the 11 to 13-week pregnancy screening test. This is usually an ultrasound and blood test.

It’s also possible to screen for Edwards syndrome through non-invasive prenatal testing (NIPT). This is a blood test taken from 10 weeks of pregnancy.

These tests can give an indication that Edwards syndrome is likely. However, the only definite way to diagnose Edwards syndrome is through genetic testing. This can be done during pregnancy using:

• chorionic villus sampling (CVS)
• amniocentesis

Both these tests have a very small risk of miscarriage. You can talk to your doctor or midwife about this.

If a diagnosis of Edwards syndrome is confirmed your doctor will talk to you about your options. This conversation will likely include a discussion about the possible termination of the pregnancy.

Sometimes, Edwards syndrome is not suspected during pregnancy, and is only discovered when your baby is born.

How is Edwards syndrome treated?

There is no cure for babies with Edwards syndrome. Unfortunately, it’s rare for a baby with full Edwards syndrome to survive their first year of life.

Babies with Edwards syndrome may need treatment in the neonatal intensive care unit. Palliative care treatment may be offered for some babies and children with this condition.

Most babies with Edwards syndrome live for only a few days or weeks after birth.

Specific treatment for Edwards syndrome focusses on health conditions, such as:

• heart problems
• breathing problems
• infections

Can Edwards syndrome be prevented?

Edwards syndrome is a genetic disease, so can’t be prevented.

The condition does not usually run in families. It’s not caused by anything you have done.

Complications of Edwards syndrome

Edwards syndrome is linked to certain physical features and health problems.

All babies born with Edwards syndrome will have some level of learning disability.