Autosomaldominant mutations of VEGFR3, which interfere with thefunctioning of the receptor as a homodimer, not only cause oneof the main forms of hereditary primary lymphostasis, namelyprimary lymphedema (Milroy’s disease), but also participatein predisposition to the development of common cyanoticcongenital heart defects, demonstrating a new function ofVEGFR3 in the early development of heart tissues (Monaghanet al., 2021). Here, FLT4 is linked to lymphedema.