FOXC2 and Myxomatous mitral valve degeneration: Furthermore, we determined the precise location of lymphatic vessels in murine MVs, and these lymphatic vessels were aberrantly expanded in EC-<i>Foxc1/c2</i> mutant mitral valves.<h4>Conclusions</h4>Our results indicate that <i>Foxc1</i> and <i>Foxc2</i> are required for maintaining the integrity of the MV, including VEC junctions, ECM organization, and lymphatic vessels to prevent myxomatous mitral valve degeneration.