What is trisomy 13 or Patau syndrome?

Trisomy 13, or Patau syndrome, is a chromosomal condition. It happens when a baby’s cells have 3 copies of chromosome 13, rather than the usual 2.

Trisomy 13 in unborn babies often leads to miscarriage or stillbirth.

Babies who survive pregnancy usually die in the first month of life. About 1 in 10 children live beyond 12 months.

Babies born with trisomy 13 often have:

low birth weight
brain and heart problems
eye defects
hand and feet anomalies
difficulties with feeding and breathing.

Children with trisomy 13 who survive beyond infancy have severe intellectual disability.

Sometimes only some of a child’s cells have an extra copy of chromosome 13. This is called mosaic Patau syndrome. Children with mosaic Patau syndrome might have a milder form of the condition.

For typical human development, we need 46 chromosomes in all 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 trisomy 13

You can have tests during pregnancy to help you find out whether your baby has trisomy 13, or Patau syndrome.

You can talk to your midwife or doctor to get more information about these tests.

Trisomy 13 can also be diagnosed at birth because there are key physical features that your doctor can see. If the doctor thinks your baby has trisomy 13, the doctor will confirm this by giving your baby a blood test or taking a swab of the inside of your baby’s cheek.

Being told that your unborn or new baby has trisomy 13 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 trisomy 13 and their families

There’s no cure for trisomy 13, or Patau syndrome.

If you’re told that your unborn baby has a chromosomal condition like trisomy 13, 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 trisomy 13, 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.

The following professionals might also be able to help you before and after your child is born:

The National Disability Insurance Scheme (NDIS) might support your child with trisomy 13, as well as you and your family. Our guide has answers to your questions about the NDIS.

What causes trisomy 13?

Trisomy 13, or Patau syndrome, is most often caused by a random genetic change during the formation of a parent’s eggs or sperm.

Less often, this change happens 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 trisomy 13.

If you have one baby with trisomy 13, the chance of having another baby with the syndrome is usually very low. But this depends on the type of condition your child has. Genetic testing can give you more information about this.