VEGFR-3 (Vascular endothelial growth factor receptor 3) is a receptor for VEGFC. VEGFR-3 has a tyrosine-protein kinase activity, and catalyzes the following reaction: ATP + a [protein]-L-tyrosine = ADP + a [protein]-L-tyrosine phosphate. Defects in VEGFR-3 are the cause of lymphedema hereditary type 1A (LMPH1A), also known as Nonne-Milroy lymphedema or Milroy disease. Hereditary lymphedema is a chronic disabling condition which results in swelling of the extremities due to altered lymphatic flow.