GCA and arterial disorder: We suggest then that the BNP/GC-A/cGMP/PDE system may represent a modifier in arterial disease onset or severity as is the case in the MRL/lpr mouse, and screening of clinical populations for expression differences, or genetic disruption of the BNP/GC-A/cGMP/PDE system could aid in developing a mechanistic understanding for many idiopathic rare arteriopathies.