Atrial Septal Defect 6
A number sign (#) is used with this entry because of evidence that atrial septal defect-6 (ASD6) is caused by heterozygous mutation in the TLL1 gene (606742) on chromosome 4q32.
For a general phenotypic description and discussion of genetic heterogeneity in atrial septal defect, see ASD1 (108800).
Molecular GeneticsBased on data from mouse models of incomplete heart septation associated with inactivation of mouse Tll1, Stanczak et al. (2009) analyzed the candidate gene TLL1 in 19 unrelated patients with atrial septal defect and identified heterozygosity for 3 missense mutations in 3 patients (606742.0001-606742.0003, respectively). One of the patients had an isolated ostium primum defect; the other 2 patients, who had ostium secundum defects, displayed additional features including interatrial aneurysm and cardiac arrhythmias.