About trisomy 13

Trisomy 13, or Patau syndrome, happens when a baby’s cells have three copies of chromosome 13, rather than the usual two.

Most unborn babies with trisomy 13 spontaneously abort or are stillborn.

Babies who survive pregnancy usually die soon after birth.

Some of the challenges faced by babies with trisomy 13, or Patau syndrome, are low birth weight, brain and heart problems, eye defects, abnormal hands and feet, and difficulties with feeding and breathing.

Some babies might have only a few features of trisomy 13, and other children might have many. The way a child is affected by trisomy 13 depends on whether all of the child’s cells contain three copies of chromosome 13, or only some of the cells.

When only some of a child’s cells have an extra copy of chromosome 13, this is called ‘mosaic’ Patau syndrome. Children with this version have a milder version of the condition.

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

For normal human development, we need 46 chromosomes (23 pairs carrying genetic material from each parent) in all of the cells in our bodies. Chromosome abnormalities are when there are missing or extra chromosomes or changes in the structure or arrangement of the chromosomes.

Causes of trisomy 13

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

Less often, this error happens after conception, while the baby is still developing in the womb.

The older a mother is when she gets pregnant, the higher the chance she has of having a baby with Patau syndrome.

If you have one baby with Patau syndrome, 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.

Diagnosis of trisomy 13

Trisomy 13, or Patau syndrome, is diagnosed with genetic tests.

Some tests can be done before birth. Other tests can be done after the baby is born.

Support and treatment for children with trisomy 13

If your baby is diagnosed with trisomy 13, or Patau syndrome, before or after birth, the following professionals might be able to help you: