Trisomy 13 Rachel Johnson

Trisomy 13, also known as Patau Syndrome, occurs as a result of an extra copy of chromosome 13 being present in some or all of the body cells.

Three copies of chromosome 13 exist instead of the normal two copies



  • Intellectual Disability


  • Cleft lip/palate
  • Extra fingers or toes
  • Abnormally small eyes, possibly fused together
  • Simian crease (one main line running across the palm)
  • Seizures
  • Heart defects
  • Undeveloped muscles
  • Low set and deformed ears
  • Loss of skin on scalp
  • Undescended testicles
  • Small extremities including limbs and the head
Top: Cleft lip Left: Polydactyly Right: Baby with Trisomy 13

What Happens Genetically?

  1. Full Trisomy 13 occurs when a complete copy of chromosome 13 is present in all of the person's body cells. This is the most severe version of Trisomy 13, and it results in many physical changes.
  2. Mosaic Trisomy 13 occurs when the extra copy of chromosome 13 is located only in some or specific types of cells. Because the copy isn't present in all cells, the symptoms tend to be on the less severe side.
  3. Partial Trisomy 13 can occur when part of chromosome 13 is translocated/attached to another chromosome. The symptoms the person experiences may be different than full or mosaic Trisomy 13.

The Stats: Frequency

  • Trisomy 13 occurs in about 1 in every 10,000 live births.
  • 90-91% of babies born with the disease do not live past their first year of life.
  • 80% of babies born with Patau Syndrome have heart defects or conditions.


Patau Syndrome is a disease that mostly cannot be inherited which is a relief to the parents of those born with the genetic disorder. Instead, the origin of the disease can be seen in how the gametes join together to form the zygote during fertilization. Full and Mosaic Trisomy 13 only occur once during a pregancy- the mother will not be able to have another child born with the disease. However, Partial Trisomy 13 is inheritable, and there is a risk of multiple pregnancies resulting in the symptoms of Patau Syndrome.

"...sometimes an egg or sperm cell will contain extra chromosomes. These extra chromosomes also get passed to the embryo and disrupt how the cells grow and develop."
The extra genetic material in the gametes explains Trisomy 13's occurrence

Treatment & Quality of Life

There is no present cure for Trisomy 13, and the majority of treatments available exist to maximize the comfort and care of both the patient and his or her parents. Teaching skills, physical therapy sessions, and problem-solving lessons are offered to those whose babies survive for longer than a week and are able to return home. Although these things appease the needs and desires of the family, the chances of the babies surviving and having a childhood are extremely slim. Therefore, because of the rarity of living babies with Trisomy 13, there are little to no descriptions of quality of life.


  • "Trisomy 13." Ohio Fetal Medicine Collaborative. Ohio Fetal Medicine Collaborative, 28 Jan. 2016. Web. 02 Mar. 2017. <>.
  • "Trisomy 13 - Genetics Home Reference." U.S. National Library of Medicine. National Institutes of Health, 28 Feb. 2017. Web. 02 Mar. 2017. <>.
  • "Trisomy 13." MedlinePlus Medical Encyclopedia. U.S. National Library of Medicine, 7 Feb. 2017. Web. 02 Mar. 2017. <>.

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