Most hereditary aortic diseases, including Marfan syndrome, are caused by mutations in a single gene. Early diagnosis and management utilizing genetic testing can slow the progression of aortic lesions and reduce the risk of dissection. In addition, since the clinical course and complications of hereditary aortic diseases tend to differ according to the causative gene, genetic testing is useful to establish a treatment and management policy tailored to each gene. When performing genetic testing, the physician should understand the principles of interpretation of test reports for pathogenicity assessment.