Your browser does not support javascript:   Search for gard hereSearch for news-and-events here.


Genetic and Rare Diseases Information Center (GARD)

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

Your Question

Can trisomy 13 happen in a fetus because the mother had a chest X-ray early in pregnancy? Can a father taking an antidepressant or an anxiety prescription contribute to the reason a baby has a trisomy? Thank you for any info you could give us.

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

Can something a parent does, before or during pregnancy, cause a fetus to have a trisomy?

As far as we know, nothing either parent does (or doesn't do) before or during pregnancy can cause a fetus or child to have a chromosome abnormality. Chromosome abnormalities most often occur as a result of a random error when an egg or sperm cell develops or after fertilization; less commonly, chromosome abnormalities may be inherited. Many parents who learn that their fetus or child has a chromosome abnormality worry that X-ray exposure, medications taken before or during pregnancy, or dietary regimes in either the mother or father may have caused the abnormality. Evidence has supported that there is nothing a parent can or cannot do to cause or prevent chromosome abnormalities. Research studies have looked at many different factors, including those mentioned above as well as chemical exposures, geographic location, and ethnicity. Up to this point in time, none of these studies have shown that these factors cause or contribute to chromosome abnormalities.[1]
Last updated: 1/10/2012

What causes trisomy 13?

Most cases of trisomy 13 are not inherited; it is often caused by random events during the formation of eggs and sperm in healthy parents (prior to conception). The condition typically results from having three copies of chromosome 13 in each cell in the body, instead of the usual two copies. This is referred to as complete, or full, trisomy 13. 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. This is referred to as translocation trisomy 13. Individuals with this type 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 in each cell; this is called partial 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.[2]
Last updated: 12/18/2012