Another potential etiology is abnormal vascular proliferation, fortified by the documented associations between FNH and vascular disorders (e.g., Osler-Weber-Rendu disease, Budd-Chiari syndrome, and congenital abnormalities of the ductus venosus ) [2–4] as well as mutations in genes such as ANGPT1 and ANGPT2 [1, 5]. The gene discussed is ANGPT2; the disease is hepatic veno-occlusive disease.