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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®

Trisomy 13

Reviewed November 2013

What is trisomy 13?

Trisomy 13, also called Patau syndrome, is a chromosomal condition associated with severe intellectual disability and physical abnormalities in many parts of the body. Individuals with trisomy 13 often have heart defects, brain or spinal cord abnormalities, very small or poorly developed eyes (microphthalmia), extra fingers or toes, an opening in the lip (a cleft lip) with or without an opening in the roof of the mouth (a cleft palate), and weak muscle tone (hypotonia). Due to the presence of several life-threatening medical problems, many infants with trisomy 13 die within their first days or weeks of life. Only five percent to 10 percent of children with this condition live past their first year.

How common is trisomy 13?

Trisomy 13 occurs in about 1 in 16,000 newborns. Although women of any age can have a child with trisomy 13, the chance of having a child with this condition increases as a woman gets older.

What are the genetic changes related to trisomy 13?

Most cases of trisomy 13 result from having three copies of chromosome 13 in each cell in the body instead of the usual two copies. The extra genetic material disrupts the normal course of development, causing the characteristic features of trisomy 13.

Trisomy 13 can also occur when part of chromosome 13 becomes attached (translocated) to another chromosome during the formation of reproductive cells (eggs and sperm) or very early in fetal development. Affected people have two normal copies of chromosome 13, plus an extra copy of chromosome 13 attached to another chromosome. In rare cases, only part of chromosome 13 is present in three copies. The physical signs and symptoms in these cases may be different than those found in full trisomy 13.

A small percentage of people with trisomy 13 have an extra copy of chromosome 13 in only some of the body's cells. In these people, the condition is called mosaic trisomy 13. The severity of mosaic trisomy 13 depends on the type and number of cells that have the extra chromosome. The physical features of mosaic trisomy 13 are often milder than those of full trisomy 13.

Related Chromosome(s)

Changes involving this chromosome are associated with trisomy 13.

  • chromosome 13

Can trisomy 13 be inherited?

Most cases of trisomy 13 are not inherited and result from random events during the formation of eggs and sperm in healthy parents. An error in cell division called nondisjunction results in a reproductive cell with an abnormal number of chromosomes. For example, an egg or sperm cell may gain an extra copy of chromosome 13. If one of these atypical reproductive cells contributes to the genetic makeup of a child, the child will have an extra chromosome 13 in each cell of the body.

Translocation trisomy 13 can be inherited. An unaffected person can carry a rearrangement of genetic material between chromosome 13 and another chromosome. These rearrangements are called balanced translocations because there is no extra material from chromosome 13. A person with a balanced translocation involving chromosome 13 has an increased chance of passing extra material from chromosome 13 to their children.

Where can I find information about diagnosis or management of trisomy 13?

These resources address the diagnosis or management of trisomy 13 and may include treatment providers.

  • Genetic Testing Registry: Complete trisomy 13 syndrome (
  • MedlinePlus Encyclopedia: Trisomy 13 (

You might also find information on the diagnosis or management of trisomy 13 in Educational resources and Patient support.

General information about the diagnosis ( and management ( of genetic conditions is available in the Handbook. Read more about genetic testing (, particularly the difference between clinical tests and research tests (

To locate a healthcare provider, see How can I find a genetics professional in my area? ( in the Handbook.

Where can I find additional information about trisomy 13?

You may find the following resources about trisomy 13 helpful. These materials are written for the general public.

You may also be interested in these resources, which are designed for healthcare professionals and researchers.

What other names do people use for trisomy 13?

  • Bartholin-Patau syndrome
  • complete trisomy 13 syndrome
  • Patau's syndrome
  • Patau syndrome
  • trisomy 13 syndrome

For more information about naming genetic conditions, see the Genetics Home Reference Condition Naming Guidelines ( and How are genetic conditions and genes named? ( in the Handbook.

What if I still have specific questions about trisomy 13?

Ask the Genetic and Rare Diseases Information Center (

What glossary definitions help with understanding trisomy 13?

atypical ; cell ; cell division ; chromosome ; cleft palate ; disability ; egg ; hypotonia ; inherited ; mosaic ; muscle tone ; nondisjunction ; palate ; rearrangement ; reproductive cells ; sperm ; syndrome ; translocation ; trisomy

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.


  • Chen M, Yeh GP, Shih JC, Wang BT. Trisomy 13 mosaicism: study of serial cytogenetic changes in a case from early pregnancy to infancy. Prenat Diagn. 2004 Feb;24(2):137-43. Review. (
  • Crider KS, Olney RS, Cragan JD. Trisomies 13 and 18: population prevalences, characteristics, and prenatal diagnosis, metropolitan Atlanta, 1994-2003. Am J Med Genet A. 2008 Apr 1;146A(7):820-6. doi: 10.1002/ajmg.a.32200. (
  • Di Giacomo MC, Susca FC, Resta N, Bukvic N, Vimercati A, Guanti G. Trisomy 13 mosaicism in a phenotypically normal child: description of cytogenetic and clinical findings from early pregnancy beyond 2 years of age. Am J Med Genet A. 2007 Mar 1;143A(5):518-20. (
  • FitzPatrick DR, Ramsay J, McGill NI, Shade M, Carothers AD, Hastie ND. Transcriptome analysis of human autosomal trisomy. Hum Mol Genet. 2002 Dec 15;11(26):3249-56. (
  • Graham EM, Bradley SM, Shirali GS, Hills CB, Atz AM; Pediatric Cardiac Care Consortium. Effectiveness of cardiac surgery in trisomies 13 and 18 (from the Pediatric Cardiac Care Consortium). Am J Cardiol. 2004 Mar 15;93(6):801-3. (
  • Hall HE, Chan ER, Collins A, Judis L, Shirley S, Surti U, Hoffner L, Cockwell AE, Jacobs PA, Hassold TJ. The origin of trisomy 13. Am J Med Genet A. 2007 Oct 1;143A(19):2242-8. (
  • Iliopoulos D, Sekerli E, Vassiliou G, Sidiropoulou V, Topalidis A, Dimopoulou D, Voyiatzis N. Patau syndrome with a long survival (146 months): a clinical report and review of literature. Am J Med Genet A. 2006 Jan 1;140(1):92-3. Review. (
  • Parker MJ, Budd JL, Draper ES, Young ID. Trisomy 13 and trisomy 18 in a defined population: epidemiological, genetic and prenatal observations. Prenat Diagn. 2003 Oct;23(10):856-60. (
  • Pont SJ, Robbins JM, Bird TM, Gibson JB, Cleves MA, Tilford JM, Aitken ME. Congenital malformations among liveborn infants with trisomies 18 and 13. Am J Med Genet A. 2006 Aug 15;140(16):1749-56. (
  • Rasmussen SA, Wong LY, Yang Q, May KM, Friedman JM. Population-based analyses of mortality in trisomy 13 and trisomy 18. Pediatrics. 2003 Apr;111(4 Pt 1):777-84. (


The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? ( in the Handbook.

Reviewed: November 2013
Published: September 28, 2015