A compound attribute that is the ratio of amount of ephrin-A4 (human) in blood to amount of brorin (human) in blood. The trait is EFNA4/VWC2 protein level ratio in blood (OBA_2055601, an Ontology of Biological Attributes id). Also known as: the ratio of amount of ephrin-A4 (human) in blood to amount of brorin (human) in blood.