At this point, the contribution of Lrg1 to brain angiogenesis and BBB differentiation is unknown but endothelial Lrg1 deficiency might interfere with the proper formation of the brain vasculature, similar to the defects observed in endoglin/CD105 heterozygous mice, which represent a model of hereditary hemorrhagic telangiectasia type 1 (Satomi 2003). This evidence concerns the gene LRG1 and hereditary hemorrhagic telangiectasia.