COL3A1 and Ehlers-Danlos syndrome, vascular type: The incidence of vEDS is estimated to be about 1 in 90,000.[14] vEDS is caused by structural defects or deficiency of pro-alpha 1 chain of type III procollagen encoded by COL3A1 which is an important component in many of the stretchable hollow organ tissues including arterial, bowel, the uterine walls, and skin.