Targeted correction of RUNX1 mutation in FPD patient-specific induced pluripotent stem cells rescues megakaryopoietic defects

Familial platelet disorder with predisposition to acute myeloid leukemia (FPD/AML) is an autosomaldominant disease of the hematopoietic system that is caused by heterozygous mutations in RUNX1. FPD/AML patients have a bleeding disorder characterized by thrombocytopenia with reduced platelet numbers and functions, and a tendency to develop AML. No suitable animal models exist for FPD/AML, as Runx1^+/-mice and zebra fish do not develop bleeding disorders or leukemia. Here we derived induced pluripotent stem cells(iPSCs) from 2 patientsina family with FPD/AML, and found that the FPD iPSCs display defects in megakaryocytic differentiation in vitro. We corrected the RUNX1 mutation in 1 FPD iPSC line through gene targeting, which led to normalization of megakaryopoiesis of the iPSCs in culture. Our results demonstrate successful in vitro modeling of FPD with patient-specific iPSCs and confirm that RUNX1 mutations are responsible for megakaryopoietic defects in FPD patients.