NRP1 and heart failure: Moreover, the Nrp1VEGF− mutant did not exhibit any of the cardiac failure, perinatal lethality, or growth defects observed in the Nrp1Y297A/Y297A hypomorph indicating that these phenotypes are attributed to the severe reduction in NRP1 protein in Nrp1Y297A/Y297A mutants rather than the lack of VEGF-NRP1 binding.