Heterotaxy Syndrome – Asplenia and Polysplenia as Indicators of Visceral Malposition and Complex Congenital Heart Disease

Abstract

Heterotaxy results from failure of the developing embryo to establish normal left-right asymmetry. Typical manifestations include abnormal symmetry and malposition of the thoraco-abdominal organs and vessels, complex congenital heart disease and extracardiac defects involving midline-associated structures. The spleen is almost always affected, and there is syndromic clustering of the malformations corresponding to the type of splenic abnormality present. This review outlines the embryologic and genetic background of the heterotaxy syndrome as well as the characteristic anatomic features, clinical manifestations, and diagnostic clues of its two main presentations with asplenia or polysplenia.

Left‐asymmetric expression of Galanin in the linear heart tube of the mouse embryo is independent of the nodal co‐receptor gene cryptic

“…Based on the observed Gal expression patterns, it is tempting to speculate that Galanin may be at least partially responsible for these L/R differences. In addition most human patients suffering from heterotaxia syndroms show AV canal defects and often display heart rhythm disorders ranging from slow atrial rhythm to complete heart blockage (Bartram et al, 2005), indicating a connection of the leftright pathway to the development of the CCS.…”

Left-right lineage analysis of the embryonicXenopusheart reveals a novel framework linking congenital cardiac defects and laterality disease

“…Whereas the overall incidence of CHDs in the general population is estimated to occur in 0.08% of live births (Ferencz et al, 1985), this incidence dramatically rises to 90% or higher for individuals exhibiting heterotaxic phenotypes (Nugent et al, 1994). CHDs in individuals with heterotaxy commonly include atrial septal defects, ventricular septal defects, transposition (or corrected transposition) of the great arteries, a double outlet right ventricle, anomalous venous return, a single ventricle and aortic arch anomalies (reviewed by Bowers et al, 1996;Bartram et al, 2005). CHDs commonly associated with isomerism include formation of two morphologically 'leftish' or 'rightish' atria, an absent or deficient atrial septum, anomalous venous return and loss of the coronary sinus (reviewed by Bowers et al, 1996;Bartram et al, 2005).…”

Ivemark syndrome-a rare entity with specific anatomical features

“…In the majority of cases major cardiac malformations reveal this condition in newborns. This is the reason for the high mortality rate (60%) before reaching the 1 st year of age 3 . Only 5 to 10% of the patients with IS reach adulthood 4 .…”