A compound attribute that is the ratio of amount of sphingomyelin phosphodiesterase (human) in blood to amount of cyclic GMP-AMP phosphodiesterase SMPDL3A (human) in blood. The trait is SMPD1/SMPDL3A protein level ratio in blood (OBA_2055656). Also known as: the ratio of amount of sphingomyelin phosphodiesterase (human) in blood to amount of cyclic GMP-AMP phosphodiesterase SMPDL3A (human) in blood.