Acknowledgements: This work was supported by funding from the Department of VA Office of Research and Development, MVP grant MVP000 and the Department of Veterans, I01-BX003362 (P.S.T.), IK2-CX001780 (S.M.D.), IK2BX005759-01 (D.K.). This publication does not represent the views of the Department of VA or the United States Government. This project was partially supported by the Baszucki Research Initiative provided to Stanford Vascular Surgery in 2022 (D.K.). S.A.L., Y.L. and Y.H.S. are supported by grants from the American Heart Association Vascular Diseases Strategically Focused Research Networks (AHA18SFRN33960114). S.A.L. is supported in part by the Jimmy and Roberta Howell Professorship in Cardiovascular Surgery at Baylor College of Medicine. P.N. is supported by grants from the National Heart, Lung, and Blood Institute (R01HL142711, R01HL148050, R01HL151283, R01HL127564, R01HL151152) and the National Human Genome Research Institute (U01HG011719). K.G.A. is supported by grants from the National Institutes of Health (NIH; 1K08HL153937) and the American Heart Association (862032). K.P. is supported by a grant from the National Heart, Lung, and Blood Institute (5-T32HL007208-43). A.R.A. is supported by award number F30-DK120062. D.M.M. is supported by the National Heart, Lung, and Blood Institute (RO1HL62594) and the John Ritter and Remembrin’ Benjamin foundations. M.G.L. is supported by the Institute for Translational Medicine and Therapeutics of the Perelman School of Medicine at the University of Pennsylvania, the NIH–NHLBI National Research Service Award postdoctoral fellowship (T32HL007843) and the Measey Foundation. R.D. is supported by the National Institute of General Medical Sciences of the NIH (R35-GM124836) and the National Heart, Lung, and Blood Institute of the NIH (R01-HL139865 and R01-HL155915). J.P.P. is supported by a grant from the NIH (K08HL159346). S.B. is supported by the Wellcome Trust (225790/Z/22/Z) and the United Kingdom Research and Innovation Medical Research Council (MC_UU_00002/7). D.M.M. is supported by a grant from the NIH (R01HL109942). C.J.W. was supported by a grant from the NIH (R01HL109946). P.T.E. is supported by grants from the NIH (1RO1HL092577, 1R01HL157635, 5R01HL139731), from the American Heart Association Strategically Focused Research Networks (18SFRN34110082) and from the European Union (MAESTRIA 965286).The current understanding of the genetic determinants of thoracic aortic aneurysms and dissections (TAAD) has largely been informed through studies of rare, Mendelian forms of disease. Here, we conducted a genome-wide association study (GWAS) of TAAD, testing ~25 million DNA sequence variants in 8,626 participants with and 453,043 participants without TAAD in the Million Veteran Program, with replication in an independent sample of 4,459 individuals with and 512,463 without TAAD from six cohorts. We identified 21 TAAD risk loci, 17 of which have not been previously reported. We leverage multiple downstream analytic methods to identify causal TAAD risk genes and cell types and provide human genetic evidence that TAAD is a non-atherosclerotic aortic disorder distinct from other forms of vascular disease. Our results demonstrate that the genetic architecture of TAAD mirrors that of other complex traits and that it is not solely inherited through protein-altering variants of large effect size
