RASA1 and arteriovenous hemangioma/malformation: Table 1 shows the main genes responsible for HHT, including all the phenotypes described to date [6,7]. Other less frequently affected genes have been described such as GDF2 and RASA-1. There is a close overlap between capillary malformation–arteriovenous malformation (CM–AVM) syndrome and HHT, both related to the RASA-1 gene mutation but expressing different phenotypes [7,8,9,10].