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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

Can you provide me with information about situs inversus?

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

How is situs inversus diagnosed?

A thorough physical examination, followed by radiographic imaging of the chest and abdomen and electrocardiography, identify most cases of situs inversus. The main diagnostic challenge in affected people is the non-traditional presence of referred pain (pain felt in a different location than its source).[1]
Last updated: 6/1/2015

How common is situs inversus?

The incidence of situs inversus is approximately 1 in 10,000, with slightly more affected males than females.[1]
Last updated: 6/1/2015

Is situs inversus inherited?

The genetics of situs inversus is complex. Several familial cases have been reported in which the inheritance has been described as either autosomal recessive (most commonly), autosomal dominant, or X-linked. The condition appears to be genetically heterogeneous, meaning that different genetic factors or genes may cause the condition among different people or families.[1] If situs inversus is associated with another underlying syndrome or condition, the inheritance pattern may be the same as that of the underlying condition.

People with questions about genetic risks to themselves or family members are encouraged to speak with a genetics professional.
Last updated: 6/1/2015

How might situs inversus be treated?

In isolated situs inversus, no treatment may be necessary. When situs inversus is associated with another condition, treatment may depend on the associated condition and the signs and symptoms present in the affected person.[1]

Knowing that a person has situs inversus is important for diagnosing medical problems and preventing surgical mishaps that can result from the failure to recognize reversed anatomy. For example, in a person with situs inversus, appendicitis causes pain in the left lower abdomen instead of the right lower abdomen.[6] Wearing medical identification can help ensure proper treatment in an emergency medical situation.
Last updated: 6/1/2015

References
  • Tiller GE, Hamid R. Situs Inversus. NORD Guide to Rare Disorders. 2003;
  • Talabi AO, Sowande OA, Tanimola AG, Adejuyigbe O. Situs inversus in association with duodenal atresia. Afr J Paediatr Surg. July-September, 2013; 10(3):275-278.
  • Annamaria Wilhelm, MD. Situs Inversus Imaging. Medscape Reference. October 2013; http://emedicine.medscape.com/article/413679-overview.
  • Alvin J Chin. Heterotaxy Syndrome and Primary Ciliary Dyskinesia. Medscape Reference. May 9, 2014; http://emedicine.medscape.com/article/896757-overview.
  • Alfred Z. Abuhamad, Rabih Chaoui. Fetal Heterotaxy, Left Atrial Isomerism, Right Atrial Isomerism, and Situs Inversus. A Practical Guide to Fetal Echocardiography: Normal and Abnormal Hearts. Philadelphia, PA: Lippincott Williams & Wilkins; 2010;
  • Annamaria Wilhelm. Situs Inversus Imaging. Medscape. October 7, 2013; http://emedicine.medscape.com/article/413679-overview#showall.
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.