First, heterozygous loss-of-function mutations in the VEGF-C [13] and FLT4 (VEGFR-3) [14,15] genes are correlated with, respectively, lymphatic malformation 4 (OMIM: 6115907) and lymphatic malformation 1 (OMIM: 153100). Here, FLT4 is linked to lymphatic malformation 1.