Summary: Background:Genes tell the body and its cells how to work. Familial platelet disease (FPD) or FPD with associated malignancies (FPDMM) is caused by a mutation in the gene RUNX1. People with this disease may have problems with their blood and bleed for a long time when they are injured. Researchers want to learn more about RUNX1 mutations and FPD.Objective:To learn more about FPD in people with RUNX...