The results of the study showed that, in skin and adventitial fibroblasts, only three isoforms were found: FBN1_001, FBN1_004, and FBN1_009. The main isoform was FBN1_001 and it was significantly reduced in skin and adventitial fibroblasts from thoracic aortic aneurysm (TAA) patients, as well as in MFS patients. This evidence concerns the gene FBN1 and Marfan syndrome.