However, vasoconstriction to a thromboxane analog (U46619) was reduced in thoracic aortas, but not in mesenteric, coronary, or carotid arteries, from the HCD females compared with controls, and was associated with lower phosphorylated myosin phosphatase target subunit 1 (MYPT1Thr855) levels. The gene discussed is PPP1R12A; the disease is heavy chain disease.