Figure 2.

Polymorphism and mutations of the thrombopoietin receptor, c-Mpl. Two polypmorphisms, c-Mpl K39N and S505A, lead to constitutive activity of c-Mpl and thrombocytosis. Somatic mutations in the juxtamembranal domain of c-Mpl also lead to constitutive activity and have been found in patients with ET and IMF.