Segregation Analysis of Rare NRP1 and NRP2 Variants in Families with Lymphedema.

Neuropilins are transmembrane coreceptors expressed by endothelial cells and neurons. NRP1 and NRP2 bind a variety of ligands, by which they trigger cell signaling, and are important in the development of lymphatic valves and lymphatic capillaries, respectively. This study focuses on identifying rare variants in the NRP1 and NRP2 genes that could be linked to the development of lymphatic malformations in patients diagnosed with lymphedema. Two hundred and thirty-five Italian lymphedema patients, who tested negative for variants in known lymphedema genes, were screened for variants in NRP1 and NRP2. Two probands carried variants in NRP1 and four in NRP2. The variants of both genes segregated with lymphedema in familial cases. Although further functional and biochemical studies are needed to clarify their involvement with lymphedema and to associate NRP1 and NRP2 with lymphedema, we suggest that it is worthwhile also screening lymphedema patients for these two new candidate genes.