A compound attribute that is the ratio of amount of porphobilinogen deaminase (human) in blood to amount of protein-glutamine gamma-glutamyltransferase 2 (human) in blood. The trait is Ontology of Biological Attributes term OBA_2053034 (HMBS/TGM2 protein level ratio in blood). Also known as: the ratio of amount of porphobilinogen deaminase (human) in blood to amount of protein-glutamine gamma-glutamyltransferase 2 (human) in blood.