The present invention relates to methods for the diagnosis and the treatment of familial thoracic aortic aneurysms caused by TGFB2 loss of function mutations. More particularly, the present invention relates to a method for determining whether a subject is predisposed to thoracic aortic aneurysms comprising detecting a TGFB2 loss of function mutation wherein the presence of the mutation indicated that the subject is predisposed to thoracic aortic aneurysms. The present invention also relates to a transforming growth factor beta-2 (TGF-β2) polypeptide for use in the prophylactic treatment of a subject who has been considered as predisposed to thoracic aortic aneurysms by the method of the invention (i.e. a subject having one TGB2 loss of function mutation according to the invention).
