Trisomy 13 and Trisomy 18 – Detailed Information

Trisomy 13 (Patau syndrome) and trisomy 18 (Edwards syndrome) are conditions that are present at birth (congenital). With these conditions, a person has an extra chromosome (trisomy) at chromosome number 13 or 18.

Chromosomes are structures that are inside of cells and made of genes. They carry the genetic information about how the body develops. Normal cells have 23 pairs of chromosomes in each cell. When there is an extra chromosome in certain cells, it can change the way a baby grows and develops in the womb.

Trisomy 13 and trisomy 18 lead to a number of serious birth defects. A baby born with one of these conditions may have a very limited life expectancy of days to weeks after birth.

What are the causes?

This condition is caused by a spontaneous change (mutation) in the chromosomes at the time sperm fertilizes an egg.

What increases the risk?

The following factors may cause trisomy 13 and trisomy 18 to be more likely:

• A history of giving birth to a baby with trisomy 13 or trisomy 18.
• The mother’s age. Females who are 35 years of age or older are more likely than younger females to have a baby with these abnormalities.

What are the signs or symptoms?

Symptoms of this condition include:

• Low birth weight.
• Serious heart defects.
• Brain structure abnormalities.
• Cleft lip and cleft palate.
• Small head.
• Periods of not breathing (apnea).
• Problems with the development of the kidneys, digestive system, feet, hands, and spine.

How is this diagnosed?

Before birth

These conditions may be diagnosed before birth if developmental abnormalities are detected during routine prenatal screenings. The diagnosis can be confirmed by doing a procedure to remove a sample of fluid from inside the womb (amniocentesis). The fluid can be tested to examine the genetic structure of fetal cells, which will show an extra chromosome.

After birth

Your baby’s health care provider may suspect trisomy 13 or trisomy 18 if multiple defects are found in your baby at birth. The diagnosis can be confirmed by testing the baby’s blood and examining the genetic structure of cells, which will show an extra chromosome.

How is this treated?

There is no treatment for trisomy 13 and trisomy 18. Your baby will be provided with the best support possible. In some cases, treatments may be done to help manage certain problems or symptoms that the condition causes.

Follow these instructions at home:

• If your child will be going home, work with all of your child’s health care providers to learn how to best care for your child.
• Talk with your child’s health care provider about your wishes and whether to put a do not attempt resuscitation (DNAR) order in place for your child.
• Talk with your child’s health care provider about palliative care services. Because this condition results in a shorter life for your child, palliative care services can help you plan for your child’s comfort and quality of life.
• Keep all follow-up visits as told by your health care provider.
• If you are concerned about having another baby with the condition, talk with your health care provider about genetic testing and counseling.

Where to find more information

• Support Organization for Trisomy 18, 13, and Related Disorders (SOFT): www.trisomy.org  

Contact a health care provider if:

• You have any questions about caring for your child in the hospital or at home.

Summary

• Trisomy 13 (Patau syndrome) and trisomy 18 (Edwards syndrome) are conditions that are present at birth (congenital). With these conditions, a person has an extra chromosome (trisomy) at chromosome number 13 or 18.
• Trisomy 13 and trisomy 18 lead to a number of serious birth defects.
• The diagnosis can be confirmed before birth with an amniocentesis or after birth with a blood sample, which will show an extra chromosome when the genetic structure is examined.
• There is no treatment for trisomy 13 or trisomy 18, but your baby will be provided with the best support possible.