How is Patau Syndrome (Trisomy 13) Diagnosed?

Patau Syndrome Can Be Diagnosed During Pregnancy

Newborn babies in hospital nursery
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Chromosomal abnormalities are responsible for miscarriages and stillbirths. Abnormalities can cause significant issues, including Down Syndrome and other developmental delays or health issues. In trisomy, individuals have three copies of a chromosome rather than two as is normal. 

Patau syndrome, or Trisomy 13, is the least common of the autosomal trisomies and most severe, after Down syndrome (Trisomy 21) and Edwards syndrome (Trisomy 18).

The extra copy of chromosome 13 in Patau syndrome causes severe neurological and heart defects which make it difficult for infants to survive. The exact cause of Patau syndrome is not known, although it appears to affect females more than males, most likely because male fetuses do not survive until birth. Patau syndrome, like Down syndrome, is associated with increased age of the mother. It may affect individuals of all ethnic backgrounds.


Newborns born with Patau syndrome often have physical abnormalities or intellectual issues. Many babies do not survive past the first month or within the first year. Other symptoms include:

  • Extra fingers or toes (polydactyly)
  • Deformed feet, known as rocker-bottom feet
  • Neurological problems such as small head (microcephaly), failure of the brain to divide into halves during gestation (holoprosencephaly), severe mental deficiency
  • Facial defects such as small eyes (microphthalmia), absent or malformed nose, cleft lip and/or cleft palate
  • Heart defects (80% of individuals)
  • Kidney defects


Patau syndrome is not very common; just 1 in 16,000 babies has the disorder. 95% of the babies with Patau syndrome die prior to birth. 


The symptoms of Patau syndrome are evident at birth. Patau syndrome may be mistaken for Edwards syndrome, so genetic testing must be done to confirm the diagnosis.

Imaging studies such as computed tomography (CT) or magnetic resonance imaging (MRI) should be done to look for brain, heart, and kidney defects. An ultrasound of the heart (echocardiogram) should be performed given the high frequency of heart defects associated with Patau syndrome.


Treatment of Patau syndrome focuses on the particular physical problems with which each child is born. Many infants have difficulty surviving the first few days or weeks due to severe neurological problems or complex heart defects. Surgery may be necessary to repair heart defects or cleft lip and cleft palate. Physical, occupational, and speech therapy will help individuals with Patau syndrome reach their full developmental potential.

What to Do

If your baby has been diagnosed with Patau syndrome prior to birth, your doctor will go over options with you. Some parents opt for intensive intervention, while others opt to end the pregnancy. Others will continue the pregnancy and provide continual care for the child's life.

While the chances for survival are extremely low, some people do decide to try intensive care to prolong the child's life. These decisions are intensely personal and can only be made by you, your partner and your doctor. 

Genetic counseling and support

Parents of a child born with Patau syndrome will receive genetic counseling to determine what their risk is of having another child with the syndrome. A good resource for information and support is the Support Organization for Trisomy 18, 13 and other Related Disorders (S.O.F.T.).

Best, R.G., Stallworth, J., & Dacus, J.V. (2002). Patau syndrome. 

"Patau Syndrome". National Library for Genetic Health, 2009. 

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