Trisomy 13

  • Definition
    • Trisomy 13 (also called Patau syndrome) is a genetic disorder in which a person has 3 copies of genetic material from chromosome 13, instead of the usual 2 copies. Rarely, the extra material may be attached to another chromosome (translocation).

  • Alternative Names
    • Patau syndrome

  • Causes
    • Trisomy 13 occurs when extra DNA from chromosome 13 appears in some or all of the body's cells.

      • Trisomy 13: the presence of an extra (third) chromosome 13 in all of the cells.
      • Trisomy 13: mosaicism, the presence of an extra chromosome 13 in some of the cells.
      • Partial trisomy: the presence of a part of an extra chromosome 13 in the cells.

      The extra material interferes with normal development.

      Trisomy 13 occurs in about 1 out of every 10,000 newborns. Most cases are not passed down through families (inherited). Instead, the events that lead to trisomy 13 occur in either the sperm or the egg that forms the fetus.

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

      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.

  • Treatment
    • There is no specific treatment for trisomy 13. Treatment varies from child to child and depends on the specific symptoms.

  • Support Groups
  • Outlook (Prognosis)
    • More than 90% of children with trisomy 13 die in the first year.

  • Possible Complications
    • Complications begin almost immediately. Most infants with trisomy 13 have congenital heart disease.

      Complications may include:

      • Breathing difficulty or lack of breathing (apnea)
      • Deafness
      • Feeding problems
      • Heart failure
      • Seizures
      • Vision problems
  • When to Contact a Medical Professional
    • Call your health care provider if you have had a child with trisomy 13 and you plan to have another child. Genetic counseling can help families understand the condition, the risk of inheriting it, and how to care for the person.

  • Prevention
    • Trisomy 13 can be diagnosed before birth by amniocentesis with chromosome studies of the amniotic cells.

      Parents of infants with trisomy 13 that is caused by a translocation should have genetic testing and counseling. This may help them avoid having another child with the condition.

  • References
    • Bacino CA, Lee B. Cytogenetics. In: Kliegman RM, Stanton BF, St. Geme JW III, Shor NF, eds. Nelson Textbook of Pediatrics. 20th ed. Philadelphia, PA: Elsevier; 2016:chap 81.