Advances have been made in the understanding and the importance of VEGF-A/PlGF heterodimers, VEGFR1/VEGFR2 heterodimers versus homodimeric ligands and/or homodimeric VEGF receptors in the context of the pathobiology of retinal diseases and other relevant organ systems. The gene discussed is FLT1; the disease is Abnormal retinal morphology.