Only recently have a few notable exceptions blurred this distinction: two RASA1-positive patients were reported with large pulmonary and hepatic AVMs mimicking HHT, and separate case series have shown that EPHB4 mutations can occasionally lead to HHT-like hepatic vascular abnormalities in older adults [39, 41]. The gene discussed is RASA1; the disease is hereditary hemorrhagic telangiectasia.