"Bicuspid aortic valve, a heart valve with only two leaflets instead of three, is the most common congenital heart defect with an estimated prevalence of about 1-2%. The heart defect often remains asymptomatic but in at least 10% of the bicuspid aortic valve patients, an ascending aortic aneurysm develops as well. If not detected in a timely fashion, this can lead to an aortic aneurysm dissection with a high mortality. In view of the prevalent nature of this heart defect, this implies an important health care problem. Historically, it was always hypothesized that abnormal blood flow across the bicuspid aortic valve led to aneurysm formation. However in recent years, the importance of a genetic contribution has been suggested based on the high heritability and it is currently believed that the same genetic factors predispose to the developmental valve defect and the aortic aneurysm formation. The inheritance pattern is most consistent with an autosomal dominant disorder with variable penetrance and expressivity. Until now, the latter have significantly hampered the causal gene identification but the era of next generation sequencing is now offering unprecedented opportunities for a major breakthrough in this area.Through detailed signalling pathway analysis, miRNA profiling and next generation sequencing, this project will contribute significantly to resolving the genetic causes of bicuspid related aortopathy, provide critical knowledge on the pathogenesis of aortic aneurysmal disease and deliver a mouse model for future therapeutical trials."