Patau Syndrome (Trisomy 13)

By Medically reviewed by hellodoktor


What is Patau Syndrome (Trisomy 13)?

Patau’s syndrome is a serious genetic disorder caused by having an additional copy of chromosome 13 in some or all of the body’s cells. It’s also called trisomy 13.

Each cell normally contains 23 pairs of chromosomes, which carry the genes you inherit from your parents.

But a baby with Patau’s syndrome has 3 copies of chromosome 13, instead of 2.

This severely disrupts normal development and, in many cases, results in miscarriage, stillbirth, or the baby dying shortly after birth.

Babies with Patau’s syndrome grow slowly in the womb and have a low birth weight, along with a number of other serious medical problems.

How common is Patau Syndrome (Trisomy 13)?

Patau’s syndrome affects about 1 in every 5,000 births. The risk of having a baby with the syndrome increases with the mother’s age. More than 9 out of 10 children (over 90%) born with Patau’s syndrome die during the first year.

About 5 to 10% of babies with less severe forms of the syndrome, such as partial or mosaic trisomy 13, live for more than a year. Please discuss with your doctor for further information.


What are the symptoms of Patau Syndrome (Trisomy 13)?

The common symptoms of Patau Syndrome (Trisomy 13) are:

  • Cleft lip or palate
  • Clenched hands (with outer fingers on top of the inner fingers)
  • Close-set eyes — eyes may actually fuse together into one
  • Decreased muscle tone
  • Extra fingers or toes (polydactyly)
  • Hernias: umbilical hernia, inguinal hernia
  • Hole, split, or cleft in the iris (coloboma)
  • Low-set ears
  • Intellectual disability, severe
  • Scalp defects (missing skin)
  • Seizures
  • Single palmar crease
  • Skeletal (limb) abnormalities
  • Small eyes
  • Small head (microcephaly)
  • Small lower jaw (micrognathia)
  • Undescended testicle (cryptorchidism)

There may be some symptoms not listed above. If you have any concerns about a symptom, please consult your doctor.

When should I see my doctor?

If you have any signs or symptoms listed above or have any questions, please consult with your doctor. Everyone’s body acts differently. It is always best to discuss with your doctor what is best for your situation.


What causes Patau Syndrome (Trisomy 13)?

Patau syndrome happens by chance and isn’t caused by anything the parents have done.

Most cases of the syndrome don’t run in families (they’re not inherited). They occur randomly during conception, when the sperm and egg combine and the foetus starts to develop.

An error occurs when the cells divide, resulting in an additional copy – or part of a copy – of chromosome 13, which severely affects the baby’s development in the womb.

In many cases, the baby dies before reaching full term (miscarriage) or is dead at birth (stillbirth).

In most cases of Patau syndrome (75 to 90%), a baby has a whole extra copy of chromosome number 13 in their body’s cells. This is sometimes known as trisomy 13 or simple trisomy 13.

In 5 to 10% of cases of Patau syndrome, genetic material is rearranged between chromosome 13 and another chromosome. This is called a chromosomal translocation.

Patau syndrome that arises because of this can be inherited.

In a further 5% of cases, only some cells have the extra copy of chromosome 13. This is known as trisomy 13 mosaicism. Occasionally, only part of one chromosome 13 is extra (partial trisomy 13).

The symptoms and features of both mosaicism and partial trisomy tend to be less severe than in simple trisomy 13, resulting in more babies living longer.

Risk factors

What increases my risk for Patau Syndrome (Trisomy 13)?

Please discuss with your doctor for further information.

Diagnosis & treatment

The information provided is not a substitute for any medical advice. ALWAYS consult with your doctor for more information.

How is Patau Syndrome (Trisomy 13) diagnosed?

The infant may have a single umbilical artery at birth. There are often signs of congenital heart disease, such as:

  • Abnormal placement of the heart toward the right side of the chest instead of the left
  • Atrial septal defect
  • Patent ductus arteriosus
  • Ventricular septal defect

Gastrointestinal x-rays or ultrasound may show rotation of the internal organs.

MRI or CT scans of the head may reveal a problem with the structure of the brain. The problem is called holoprosencephaly. It is the joining together of the 2 sides of the brain.

Chromosome studies show trisomy 13, trisomy 13 mosaicism, or partial trisomy.

How is Patau Syndrome (Trisomy 13) treated?

There’s no specific treatment for Patau’s syndrome. As a result of the severe health problems a newborn baby with the syndrome will have, doctors usually focus on minimising discomfort and ensuring the baby is able to feed.

For the small number of babies with Patau’s syndrome who survive beyond the first few days of life, their care will depend on their specific symptoms and needs.

If your baby is diagnosed with Patau’s syndrome, either before birth or shortly afterwards, you’ll be offered counselling and support.

Lifestyle changes & home remedies

What are some lifestyle changes or home remedies that can help me manage Patau Syndrome (Trisomy 13)?

If you have any questions, please consult with your doctor to better understand the best solution for you.

Hello Health Group does not provide medical advice, diagnosis or treatment.


Review Date: August 16, 2018 | Last Modified: September 13, 2019

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