A compound attribute that is the ratio of amount of megakaryocyte and platelet inhibitory receptor G6b (human) in blood to amount of plexin-A4 (human) in blood. The trait is MPIG6B/PLXNA4 protein level ratio in blood (OBA_2054543, an Ontology of Biological Attributes entry). Also known as: the ratio of amount of megakaryocyte and platelet inhibitory receptor G6b (human) in blood to amount of plexin-A4 (human) in blood.