PHACTR1 and spontaneous coronary artery dissection: Notably, the association of the SCAD risk score supports a hypothesis previously suggested by the PHACTR1 locus association patterns16, of sex-dimorphic and opposing influences on vascular biology, whereby one end of the spectrum of risk leads to arterial fragility and predisposition to arterial dissection with resulting MI, predominantly in women, and the other end of the spectrum of risk contributes to susceptibility to coronary atherosclerotic MI, a disease that affects both sexes but occurs more often in men.