When we filtered variants that were present in all three exome-sequenced afflicted individuals (II:2, II:3, and II:8) but absent from the >1000 exomes present in our local database, we identified sequence variants in SEMA4A, PLCZ1, FBLN5, SPG11, and RANBP2. None of these genes have been previously associated with FTAAD. This evidence concerns the gene SEMA4A and familial thoracic aortic aneurysm and aortic dissection.