Trisomy 13 - Patau Syndrome

Trisomy 13 and Premature Birth

Extra fingers in trisomy 13.
Extra fingers are a symptom of trisomy 13.. By Chan A et al CC-BY-2.0, via Wikimedia Commons

 What is Trisomy 13?

Trisomy 13, also called Patau syndrome, is a genetic defect involving chromosome 13. Most people have 23 chromosome pairs, but people with Patau syndrome have an extra copy of the thirteenth chromosome. Trisomy 13 is a serious genetic syndrome, and most babies with Patau syndrome die before birth or within the first week of life.

There are 3 types of trisomy 13:

  • Full trisomy: Most cases of trisomy 13 are full trisomies. In full trisomies, every cell in the body contains three copies of chromosome 13.
  • Partial trisomy: Patients with partial trisomies do not have a whole extra copy of chromosome 13. Rather, they have an extra part of the chromosome attached to another chromosome in their cells.
  • Mosaic: Patients with trisomy 13 mosaic have an entire extra copy of chromosome 13, but only in some of the body's cells.

Trisomy 13 is usually caused by an error in cell division. Although the risk of having a baby with trisomy 13 is higher in older moms, it is not inherited and cannot be passed down in families. The only exception is partial trisomy 13, which can be inherited. Any family with a history of trisomy 13 should have genetic counseling.

Symptoms of Patau Syndrome

Because the extra chromosome is present throughout the body, trisomy 13 can cause problems in many body systems. Some symptoms of trisomy 13 can be treated with medication or surgery, but others are untreatable. Symptoms include:

  • Premature birth: Many trisomy 13 pregnancies end in miscarriage or stillbirth. Babies who are born alive are usually born early, with an average gestational age of 29 weeks. These babies must battle complications of prematurity as well as other symptoms of trisomy 13.
  • Facial abnormalities: Many babies with trisomy 13 are born with a cleft lip and/or a cleft palate. Eyes can be set close together, and may fuse together to form one eye. Ears can be low set, and skin problems on the scalp (cutis aplasia) are common. 
  • Heart problems: Heart defects are common in babies with trisomy 13. Holes between the heart chambers (ventricular septal defect and atrial septal defect) and patent ductus arteriosus can both be found in trisomy 13.
  • Problems in the brain: In some children with trisomy 13, the front of the brain does not divide properly. This causes many of the facial problems associated with the disorder. Children with Patau syndrome have severe mental disabilities, and may have seizures.
  • Gastrointestinal problems: GI problems in children with trisomy 13 can include umbilical hernias and inguinal hernias. Omphaloceles, where part of the intestines are outside the body, occur in some cases.
  • Skeletal problems: Babies with Patau syndrome may have extra fingers or toes, clenched hands, or misshapen (rocker-bottom) feet.
  • Breathing problems: Babies born with trisomy 13 often have trouble breathing, or have periods when they stop breathing (apnea).

How Often Do Babies with Trisomy 13 Survive?

Trisomy 13 is a serious disorder.

Most babies with trisomy 13 die within the first week, and the average lifespan is about 5 days. About 10% live to their first birthday. Babies who weigh more at birth and who have a mosaic or partial trisomies may be more likely to survive.

Although trisomy 13 is considered a lethal disorder that is not compatible with life, modern medicine has increased the lifespan and quality of life of some children with Patau syndrome.  Depending on the severity of other symptoms, surgery may help fix heart or GI defects or repair a cleft. Appropriate medical treatment has helped many children with trisomy 13 to be a great joy to their families for many years.

If your baby has trisomy 13, you do not have to face this syndrome alone. Support groups and websites can help you better understand Patau syndrome and reach out to other families touched by trisomy 13. Speaking with a perinatal hospice expert can help you learn what to expect if your baby does not survive to hospital discharge, and help you decide what types of interventions you want for your baby.


Rios, A., Furdon, S., Adams, D., & Clark, D. (2004). "Recognizing the Clinical Features of Trisomy 13 Syndrome." Advances in Neonatal Care. Retrieved from: MD

Nelson, K., Hexem, K., & Feudtner, C. (May 2012). "Inpatient Hospital Care of Children With Trisomy 13 and Trisomy 18 in the United States." Pediatrics. 129(5) 869 -876.

Swanson, J. & Sinkin, R. (Dec. 2013). Clinics in Perinatology. "Early Births and Congenital Birth Defects: A Complex Interaction." 40(4):629-44.

Genetics Home Reference. "Trisomy 13." Retrieved from

Continue Reading