THE EHLERS-DANLOS syndrome (E-D) is a hereditary disorder of connective tissue wherein the pathogenesis is not clear. The phenotypic expression is exceedingly variable, such that minimally affected individuals may pass as "normal." Because of this, McKusick1speculates that E-D may actually be the most common of the heritable connective-tissue disorders. However, in the face of this, many aspects of this syndrome, including cardiovascular and systemic effects, remain to be explained. The purpose of this report is to present a family study of E-D wherein the proband was severely affected and died from rupture of an aneurysm of the thoracic aorta. At autopsy, he was found to have a fistula between the abdominal aorta and the inferior vena cava, as well as between the left common iliac artery and vein. So far as we can determine, this is the first report of E-D showing such fistulae. Report of a Case