Incidence rates of major arterial/venous thrombosis for JAK2, type 1/type 1-like CALR, type 2/type 2-like CALR, MPL-mutated and TN cases were 14%/8%, 11%/6%, 12%/9%, 13%/0%, and 6%/2%, respectively. The gene discussed is MPL; the disease is deep vein thrombosis.