HBEGF and fibrosis: In particular, the cardiac fibrosis observed in Rhbdf1-null mice resembles the heart enlargement displayed by Hbegf-null mice (Iwamoto et al. 2003), and the eyelids open at birth (EOB) observed in Rhbdf1:Rhbdf2 double KO mice resembles the EOB phenotype displayed by Hbegf and Tgfa double null mice (Mine et al. 2005).