(Ghalamkarpour et al., 2009; Connell et al., 2013; Online Mendelian Inheritance in Man, 2021) Transgenic mice that express a soluble (i.e., inactivating) form of VEGFR3 have impaired fetal lymphangiogenesis, regression of lymphatic vessels, and a lymphedema-like phenotype including hindlimb swelling and dermal fibrosis. This evidence concerns the gene FLT4 and lymphedema.