Mutations in the COL3A1 gene cause Ehlers-Danlos syndrome, Vascular Type found on the long of Chromosome 2. The protein made by the COL3A1 gene is used to assemble larger molecules called type III collagens. Collagens provide structure and strength to connective tissue throughout the body. Type III collagen is mostly found in skin, blood vessels, and internal organs. If the structure or production of type III collagen is altered by a mutation in the COL3A1 gene, collagen fibrils cannot be assembled properly in these tissues, and the symptoms of Ehlers-Danlos syndrome result.
http://ghr.nlm.nih.gov/condition=ehlersdanlossyndromevasculartype