COL1A2 and Mitral regurgitation: The complete absence of proα2(I) chains, caused by homozygosity or compound heterozygosity for COL1A2 null mutations, define a subset of EDS patients, with hypermobility and a potential risk for cardiac valvular disease (aortic and mitral valve regurgitation are described), beyond the classical stigmata of EDS (skin and joint involvement) [7,8].