Genetic abnormalities in bicuspid aortic valve root phenotype: preliminary results

OBJECTIVES: Genetic defects associated with bicuspid aortopathy have been infrequently analysed. Our goal was to examine the prevalence of rare genetic variants in patients with a bicuspid aortic valve (BAV) with a root phenotype using next-generation sequencing technology.

METHODS: We investigated a total of 124 patients with BAV with a root dilatation phenotype who underwent aortic valve ± proximal aortic surgery at a single institution (BAV database, n  = 812) during a 20-year period (1995-2015). Cross-sectional follow-up revealed 63 (51%) patients who were still alive and willing to participate. Systematic follow-up visits were scheduled from March to December 2015 and included aortic imaging as well as peripheral blood sampling for genetic testing. Next-generation sequencing libraries were prepared using a custom-made HaloPlex HS gene panel and included 20 candidate genes known to be associated with aortopathy and BAV. The primary end-point was the prevalence of genetic defects in our study cohort.

RESULTS: A total of 63 patients (mean age 46 ± 10 years, 92% men) with BAV root phenotype and mean post-aortic valve replacement follow-up of 10.3 ± 4.9 years were included. Our genetic analysis yielded a wide spectrum of rare, potentially or likely pathogenic variants in 19 (30%) patients, with NOTCH1 variants being the most common ( n  = 6). Moreover, deleterious variants were revealed in AXIN1 ( n  = 3), NOS3 ( n  = 3), ELN ( n  = 2), FBN1 ( n  = 2) , FN1 ( n  = 2) and rarely in other candidate genes.

CONCLUSIONS: Our preliminary study demonstrates a high prevalence and a wide spectrum of rare genetic variants in patients with the BAV root phenotype, indicative of the potentially congenital origin of associated aortopathy in this specific BAV cohort.