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Diseases

Genetic and Rare Diseases Information Center (GARD)

Situs inversus


Other Names for this Disease
  • Complete situs inversus
  • Complete situs inversus viscerum
  • Situs inversus totalis
  • Situs inversus viscerum
  • SIV
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

My husband has situs inversus. Is the brain turned around or otherwise affected in individuals with this condition?

Our Answer

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

What is situs inversus?

Situs inversus is a condition in which the arrangement of the internal organs is a mirror image of normal anatomy. It can occur alone (isolated, with no other abnormalities or conditions) or it can occur as part of a syndrome with various other defects. Congenital heart defects are present in about 5-10% of affected people. The underlying cause and genetics of situs inversus are complex. Familial cases have been reported.[1][2]
Last updated: 6/1/2015

What are the signs and symptoms of situs inversus?

In isolated situs inversus (occurring alone with no other abnormalities), there is a complete mirror image transposition of the thoracic (chest) and abdominal organs, and anterior-posterior (front-back) symmetry is normal. Many affected people have no associated health issues when the condition is isolated. When situs inversus occurs in association with other conditions such as Kartagener syndrome or primary ciliary dyskinesia, additional signs and symptoms relating to these conditions will be present.[1]
Last updated: 8/28/2015

What other features or conditions may be associated with situs inversus?

Situs inversus may be isolated (occurring alone with no other abnormalities) or it may be associated with other abnormalities or conditions.

Dextrocardia can occur with situs inversus. Dextrocardia means that the heart lies on the right side of the body, and the apex (tip) of the heart points to the right instead of the left.

Situs inversus can also occur in association with syndromes such as Kartagener syndrome or another primary ciliary dyskinesia (PCD). Kartagener syndrome affects about 20% of people with situs inversus; however, only about half of people with Kartagener syndrome have situs inversus.[3] Kartagener syndrome can be diagnosed after birth. PCD is present in about one fourth of people with situs inversus totalis, and situs inversus totalis is present in nearly half of people with PCD.[4]

Specific abnormalities that have been associated with situs inversus include incomplete transposition of thoracic (chest) or abdominal organs, various congenital heart defects, polysplenia (more than one spleen), asplenia (absent spleen), annular (ring-shaped) pancreas, horseshoe kidney, and diaphragmatic hernia.[1]

The incidence of congenital heart defects is increased to up to 5% in people with situs inversus. Associated heart abnormalities may include ventricular septal defect, tetralogy of Fallot, double outlet right ventricle, and/or complete or corrected transposition of the arteries. Extra-cardiac malformations (affecting parts of the body other than the heart) are not typically found in people with situs inversus.[5]
Last updated: 8/28/2015

Are the brains of individuals with situs inversus turned around or otherwise affected by the disease?

Findings from several articles support the concept that brain abnormalities (specifically asymmetry) may be found in individuals who have situs inversus.[6][7][8][9] At least one study found evidence which supported the concept that a reversal of more commonly found intracranial anatomy may occur in situs inversus totalis.[7] 
 
You can find articles relevant to this topic through PubMed, a searchable database of biomedical journal articles. Although not all of the articles are available for free online, most articles listed in PubMed have a summary available. To obtain the full article, contact a medical/university library or your local library for interlibrary loan. You can also order articles online through the publisher’s Web site. Using "situs inversus AND brain abnormalities" as your search term should help you locate articles. Use the advanced search feature to narrow your search results. Click here to view a search.
http://www.ncbi.nlm.nih.gov/PubMed

The National Library of Medicine (NLM) Web site has a page for locating libraries in your area that can provide direct access to these journals (print or online). The Web page also describes how you can get these articles through interlibrary loan and Loansome Doc (an NLM document-ordering service). You can access this page at the following link http://nnlm.gov/members/. You can also contact the NLM toll-free at 888-346-3656 to locate libraries in your area.

Last updated: 7/19/2010

References
Other Names for this Disease
  • Complete situs inversus
  • Complete situs inversus viscerum
  • Situs inversus totalis
  • Situs inversus viscerum
  • SIV
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.