Trisomy 13

Trisomy 13 (Patau syndrome) is a rare genetic condition that happens when your baby is born with an extra copy of chromosome 13. Instead of having two copies, they have three. This is called trisomy.

Learning that your baby has trisomy 13 can feel overwhelming. The condition can affect how your baby develops before birth. It can cause serious differences in their brain, heart, face and other parts of their body. Some babies have mild symptoms, but many have severe, life-threatening medical problems.

Many babies with trisomy 13 need special care right after birth. Your baby may go to the neonatal intensive care unit (NICU). Your healthcare team will work with you to create a care plan based on your baby’s needs.

Trisomy 13 occurs in about 1 out of 10,000 live births. Many affected pregnancies end in miscarriage or stillbirth. Among babies born alive, 10% to 25% survive beyond their first birthday.

Trisomy 13 symptoms

Trisomy 13 can affect many parts of your baby’s body. Symptoms vary from child to child. Some babies are more severely affected than others.

Patau syndrome symptoms can include:

• Heart defects present at birth
• Growth differences
• Developmental delays
• Intellectual disability
• Underdeveloped internal organs

Physical symptoms

Physical symptoms may include:

• Cleft lip or cleft palate
• Trouble gaining weight
• Extra fingers or toes
• Low-set ears
• Differences in arm or leg development
• Low muscle tone
• A small head and lower jaw
• Very small, closely spaced or underdeveloped eyes

Internal organ symptoms

Trisomy 13 can also affect your baby’s internal organs and body systems. Symptoms may include:

• Hearing loss
• Vision problems
• Digestive issues that make feeding difficult
• Underdeveloped lungs
• Heart problems

These complications can be life-threatening. Babies who survive beyond infancy may continue to have complex medical needs. This can include a higher risk of seizures and some cancers.

What is the cause of trisomy 13?

Trisomy 13 happens when your baby has an extra copy of chromosome 13.

Chromosomes contain your DNA. DNA carries the instructions your body uses to grow and function. Most people have 46 chromosomes arranged in 23 pairs. Babies with trisomy 13 have 47 chromosomes because of the extra copy of chromosome 13.

The extra chromosome usually happens by chance while the egg or sperm is forming. Nothing you did before or during pregnancy caused trisomy 13.

There are three types of trisomy 13:

• Complete trisomy 13: This is the most common type. Every cell in your baby’s body has an extra copy of chromosome 13.
• Translocation trisomy 13: In about 1 out of 5 cases, the extra chromosome 13 attaches to another chromosome instead of existing as a separate chromosome.
• Mosaic trisomy 13: This rare type happens when only some of your baby’s cells have the extra chromosome. Symptoms can vary depending on how many cells are affected.

How doctors diagnose this condition

Your healthcare provider may suspect trisomy 13 during pregnancy based on prenatal screening tests or ultrasound findings. Screenings can begin during the first trimester.

To confirm the diagnosis, your provider may recommend genetic testing before birth. They may also perform testing after your baby is born.

A karyotype test is the most common test providers use to confirm Patau syndrome.

How is trisomy 13 treated?

There isn’t a cure for trisomy 13. Treatment focuses on managing symptoms and giving your child the best possible quality of life.

Depending on your child’s needs, treatment may include:

• Medicines
• Surgery to treat certain birth differences
• Physical, occupational and speech therapy
• Educational support

Some babies need intensive medical care after birth. Others may benefit from comfort-focused care. Your healthcare team will talk with you about your baby’s treatment options. They’ll help you make decisions that fit your family’s goals.

Many pregnancies affected by trisomy 13 end in miscarriage or stillbirth. If you’ve experienced a pregnancy loss, you can get support. Your healthcare provider can connect you with counseling, grief services and other resources.

When should my child see their healthcare provider?

Contact your child’s provider right away if they have:

• Trouble feeding
• Difficulty breathing
• An irregular heartbeat
• Seizures

Trisomy 13 life expectancy

Trisomy 13 is a serious condition, and the outlook is often poor.

Many pregnancies end in miscarriage or stillbirth. Among babies born alive, many survive only days or weeks. About 10% to 25% live beyond their first birthday.

If your baby is diagnosed with trisomy 13, your healthcare team will help you understand what to expect. They’ll support you as you make decisions about your child’s care.

What’s the difference between trisomy 13 and trisomy 18?

An extra chromosome causes both genetic conditions. In trisomy 13, there’s an extra copy of chromosome 13. In trisomy 18 (Edwards syndrome), there’s an extra copy of chromosome 18.

Both conditions can cause serious birth differences and life-threatening complications. Many affected pregnancies end in miscarriage or stillbirth. Babies born with either condition often have a shortened life expectancy.