PTPRC and hereditary hemorrhagic telangiectasia: Nrp1SM22KO mice have shown a direct connection of artery to vein that resembles a large AVF commonly seen in cerebral and pulmonary AVMs in patients with HHT (5, 30); these mice also show dilated vessels with decreased SMC lining, along with increased infiltration of CD45+ and CD68+ cells in adult lung and liver.