Aortic aneurysm and dissection cause significant morbidity and mortality. There 
are several known single gene disorders that predispose to isolated aortic 
disease and eventually aneurysm and dissection. FBN1 mutations are associated 
with multiple clinical phenotypes, including Marfan syndrome (MFS), MASS 
phenotype, and familial ectopia lentis, but rarely with isolated aortic aneurysm 
and dissection. In this report, we describe three patients who presented with 
primary descending thoracic aortic dissection and who were found to have an FBN1 
mutation. None of the patients fulfilled clinical criteria for the diagnosis of 
MFS, and all had few or none of the skeletal features typical of the condition. 
Two patients had a history of long-term hypertension, and such a history was 
suspected in the third patient. These observations suggest that some individuals 
with FBN1 mutations have significant aortic disease involvement of other systems 
that is typical of FBN1 mutation-related syndromes. Superimposed risk factors, 
such as hypertension, may weaken the aortic wall and eventually lead to aortic 
dissection. Given that the cost continues to decrease, we suggest that 
diagnostic DNA sequencing for FBN1 mutations in patients with thoracic aortic 
aneurysms and dissection may be a practical clinical step in evaluating such 
patients and at-risk family members.