National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Situs inversus


Other Names:
Situs inversus viscerum; SIV
Categories:
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
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
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
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

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.
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.[3] Wearing medical identification can help ensure proper treatment in an emergency medical situation.
Last updated: 6/1/2015
The long-term outlook (prognosis) for people with situs inversus depends on whether the condition is isolated, or is associated additional abnormalities affecting the heart or other parts of the body. Isolated situs inversus has an excellent prognosis, typically with an uneventful prenatal and postnatal course.[4] When situs inversus is associated with an underlying condition or syndrome, the prognosis may depend on that of the underlying condition present.

For fetuses diagnosed with situs inversus on prenatal ultrasound, additional testing such as fetal MRI and fetal echocardiography may provide additional information about the development of the fetus, which may affect management and prognosis.[5] Additional imaging tests are also recommended after birth to further clarify any associated abnormalities that may be present. People who learn of a diagnosis made by prenatal ultrasound are encouraged to meet with a genetic counselor or other genetics professional.

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.[3] Wearing medical identification can help ensure proper treatment in an emergency medical situation.
Last updated: 8/28/2015

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • ClinicalTrials.gov lists trials that are related to Situs inversus. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.

    Please note: Studies listed on the ClinicalTrials.gov website are listed for informational purposes only; being listed does not reflect an endorsement by GARD or the NIH. We strongly recommend that you talk with a trusted healthcare provider before choosing to participate in any clinical study.
  • The Research Portfolio Online Reporting Tool (RePORT) provides access to reports, data, and analyses of research activities at the National Institutes of Health (NIH), including information on NIH expenditures and the results of NIH-supported research. Although these projects may not conduct studies on humans, you may want to contact the investigators to learn more. To search for studies, enter the disease name in the "Text Search" box. Then click "Submit Query".

Patient Registry

  • A registry supports research by collecting of information about patients that share something in common, such as being diagnosed with Situs inversus. The type of data collected can vary from registry to registry and is based on the goals and purpose of that registry. Some registries collect contact information while others collect more detailed medical information. Learn more about registries.

    Registries for Situs inversus:
    CHD GENES Study
     

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

In-Depth Information

  • Medscape Reference has information on situs inversus. You may need to register to view this medical reference, but registration is free.
  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Situs inversus. Click on the link to view a sample search on this topic.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know.

  1. Tiller GE, Hamid R. Situs Inversus. NORD Guide to Rare Disorders. 2003; https://rarediseases.org/rare-diseases/dextrocardia-with-situs-inversus/.
  2. 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. https://www.ncbi.nlm.nih.gov/pubmed/24192475.
  3. Annamaria Wilhelm. Situs Inversus Imaging. Medscape. October 7, 2013; http://emedicine.medscape.com/article/413679-overview#showall.
  4. 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;
  5. Nemec SF, et. al. Situs anomalies on prenatal MRI. Eur J Radiol. April, 2012; 81(4):e495-501.