Relationships of the tricuspid valve to the membranous ventricular septum in Down's syndrome without endocardial cushion defect: study of 28 specimens, 14 with a ventricular septal defect.
The commissure between the anterior and medial leaflets of the tricuspid valve is commonly absent in Down's syndrome without endocardial cushion defect (19 of 28 specimens). As a result, aneurysm of the membranous ventricular septum may develop (eight of 14 specimens with ventricular septal defect limited to the membranous ventricular septum) and the potential for left ventricle-to-right atrial communication is increased.
D004314:Down Syndrome / Q000473:pathology*; D006322:Heart Aneurysm / Q000473:pathology; D006343:Heart Septal Defects; D006345:Heart Septal Defects, Ventricular / Q000473:pathology*; D006352:Heart Ventricles / Q000002:abnormalities; D006801:Humans; D009206:Myocardium / Q000473:pathology; D014261:Tricuspid Valve / Q000002:abnormalities*