CCBE1 (Collagen and Calcium Binding EGF Domains 1): CCBE1 is a gene crucial for lymphangiogenesis, the development of lymphatic vessels. It regulates vascular endothelial growth factor C (VEGF-C), an important factor in the formation of the lymphatic system. Mutations in CCBE1 can lead to Hennekam syndrome, a rare condition characterised by lymphedema, lymphangiectasia, and intellectual disability.