Protocol Title: Safety and Feasibility of Autologous CD34+ Hematopoietic Stem Cells Mobilization and Apheresis in Participants With RUNX1 Familial Platelet Disorder

Inclusion Criteria: Participants who meet all of the following criteria are eligible to be included in the study: 1. Are aged ≥ 18 to 75 years a. Once a favorable review of safety has been completed by the SMC in 3 participants aged ≥ 18 years, the study will be opened to participants aged ≥ 12 years. 2. Are willing and able to provide informed consent, as appropriate (either directly or through a legally authorized representative \[LAR\]), as described in Appendix 1, Section 13.1 3. Have a confirmed diagnosis of RUNX1 FPD, verified by a Clinical Laboratory Improvement Amendments (CLIA)-…