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Diseases

Genetic and Rare Diseases Information Center (GARD)

Trisomy 13


Other Names for this Disease
  • Patau syndrome
  • Chromosome 13, trisomy 13 complete
  • Complete trisomy 13 syndrome
  • D trisomy syndrome (formerly)
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Cause

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What causes trisomy 13?

Most cases of trisomy 13 are caused by random events during the formation of eggs or sperm in healthy parents (prior to conception). Trisomy 13 is typically due to having three full copies of chromosome 13 in each cell in the body, instead of the usual two copies. This is referred to as complete trisomy 13 or full trisomy 13. The extra genetic material present disrupts the normal course of development, causing the characteristic features of the disorder.

Trisomy 13 can also occur when part of chromosome 13 becomes attached (translocated) to another chromosome during the formation of eggs or sperm, or very early in fetal development. This is referred to as translocation trisomy 13. People with this type of trisomy 13 have the normal two normal copies of chromosome 13, plus an extra copy of chromosome 13 that is attached to another chromosome. Translocation trisomy 13 can be inherited.

In rare cases, only part of chromosome 13 is present in three copies in each cell (rather than the full chromosome); this is called partial trisomy 13. In other rare cases, a person has an extra copy of chromosome 13 in only some of the body's cells; this is called mosaic trisomy 13. The severity of mosaic trisomy 13 depends on the type and proportion of cells that have the extra chromosome.[1]
Last updated: 9/3/2015

References
  1. Trisomy 13. Genetics Home Reference. January 2009; http://ghr.nlm.nih.gov/condition/trisomy-13. Accessed 2/2/2011.


Other Names for this Disease
  • Patau syndrome
  • Chromosome 13, trisomy 13 complete
  • Complete trisomy 13 syndrome
  • D trisomy syndrome (formerly)
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.