Timp1 mouse models are susceptible to the development of aortic aneurysms[24, 25] and TIMP1 is known to be reduced in TAA in humans.[16, 26] Additionally, overexpression of Timp1 prevents aneurysm degradation and rupture in a rat model.[27] We therefore hypothesized that reduced copy number of TIMP1 in Turner syndrome increases the risk for BAV/TAD. Here, TIMP1 is linked to aneurysm.