The term 'atrioventricular septal defect' (AVSD) covers a spectrum of congenital heart malformations characterized by a common atrioventricular junction coexisting with deficient atrioventricular septation. In ostium primum atrial septal defect (ASD) there are separate atrioventricular valvar orifices despite ... The term 'atrioventricular septal defect' (AVSD) covers a spectrum of congenital heart malformations characterized by a common atrioventricular junction coexisting with deficient atrioventricular septation. In ostium primum atrial septal defect (ASD) there are separate atrioventricular valvar orifices despite a common junction, whereas in complete AVSD the valve itself is also shared (summary by Craig, 2006). AVSD, also designated endocardial cushion defect or atrioventricular canal defect (AVCD), is known to occur in either a nonsyndromic (isolated) form or, more commonly, as part of a malformation syndrome. The 2 syndromes most frequently associated with AVSD are Down syndrome (190685), in which AVSD is the most frequent congenital heart defect, and Ivemark syndrome (208530) (summary by Carmi et al., 1992). For a discussion of genetic heterogeneity of atrioventricular septal defects, see AVSD1 (606215).
In a Hispanic patient with atrioventricular septal defect, Maitra et al. (2010) identified heterozygosity for a gain-of-function missense mutation in the GATA6 gene (A178V; 601656.0004). No DNA was available from family members, but the mutation was not found ... In a Hispanic patient with atrioventricular septal defect, Maitra et al. (2010) identified heterozygosity for a gain-of-function missense mutation in the GATA6 gene (A178V; 601656.0004). No DNA was available from family members, but the mutation was not found in 288 control individuals, including 96 of Hispanic ethnicity. The patient had unbalanced AVSD, hypoplastic left ventricle, and 2 muscular ventricular septal defects with no additional evidence of heterotaxy syndrome (see 306955).