Human Laterality Disorders: Pathogenesis, Clinical Manifestations, Diagnosis, and Management

Am J Med Sci. 2021 Sep;362(3):233-242. doi: 10.1016/j.amjms.2021.05.020. Epub 2021 May 28.


Human laterality disorders comprise a group of diseases characterized by abnormal location (situs) and orientation of thoraco-abdominal organs and vessels across the left-right axis. Situs inversus totalis is mirror image reversal of thoraco-abdominal organs/great vessels. Situs ambiguus, better known as heterotaxy, is abnormal arrangement of thoraco-abdominal organs across the left-right axis excluding situs inversus totalis. Heterotaxy, also referred to as atrial or atrial appendage isomerism, is characterized by abnormal location of left-sided or right-sided organs with loss of asymmetry of normally paired asymmetric organs. It is associated with a variety of anomalies involving the heart, great vessels, lungs and intra-abdominal organs. Right and left atrial isomerism are associated with multiple complex congenital cardiac and vascular anomalies, many of which are lethal when untreated. Isomerism may also affect the lungs, spleen, liver, gall bladder, and intestines. Innovative surgical therapy of heterotaxy/isomerism has reduced early mortality and markedly improved long-term prognosis.

Keywords: Atrial Isomerism; Congenital Heart Disease; Heterotaxy; Human Laterality Disorders; Situs Ambiguus.

Publication types

  • Review

MeSH terms

  • Dextrocardia / diagnostic imaging
  • Dextrocardia / epidemiology
  • Dextrocardia / surgery
  • Disease Management*
  • Heart Defects, Congenital / diagnostic imaging
  • Heart Defects, Congenital / epidemiology
  • Heart Defects, Congenital / surgery
  • Heterotaxy Syndrome / diagnostic imaging*
  • Heterotaxy Syndrome / epidemiology
  • Heterotaxy Syndrome / surgery*
  • Humans
  • Situs Inversus / diagnostic imaging*
  • Situs Inversus / epidemiology
  • Situs Inversus / surgery*