Platelet Disorder, Familial, With Associated Myeloid Malignancy

To evaluate the safety and feasibility of collecting hematopoietic stem cells (HSC) in participants with RUNX1-FPD.

Background:
Runt-related transcription factor 1 (RUNX1) gene regulates the formation of blood cells. People with mutations of this gene may bleed or bruise easily; they are also at higher risk of getting cancers of the blood, bone marrow, and lymph nodes.
Objective:
To test a drug (imatinib) in people with RUNX1 mutations that cause symptoms.
Eligibility:
Adults aged 18 and older with RUNX1 mutations. Healthy people without this mutation, including family members of affected participants, are also needed.
Design:
Participants with the RUNX1 mutation will be screened. They will have a physical exam with blood and urine tests. They will have a test of their heart function. They may need a new bone marrow biopsy: A sample of soft tissue will be removed from inside a bone.
Imatinib is a tablet taken by mouth once a day, every day, at home. Affected participants in different parts of the study will take imatinib for either 28 days or up to 84 days.
Participants will visit the clinic once a week for the first 28 days that they are taking the imatinib. Then they will come once every 2 weeks if they are taking the drug for 84 days. Blood, urine, and tests of heart function will be repeated. They may opt to have the bone marrow biopsy repeated after they finish their course of imatinib.
Participants will have a follow-up visit 30 days after they stop taking imatinib.
Participants who do not have the RUNX1 mutation will have 1 clinic visit. They will have blood tests. They will fill out questionnaires. They may opt to have a bone marrow biopsy....

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 variant 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 variants and FPD.
Objective:
To learn more about FPD in people with RUNX1 variants to lead to better diagnosis, monitoring, and treatment.
Eligibility:
People any age with a suspected or confirmed RUNX1 variant
People who have a family member with the variant
Design:
All participants will be screened with a phone call and a blood, saliva, or cheek cell sample.
Participants with a suspected or confirmed variant will have 1 visit. It will last about 2 days. They will then have visits at least once a year.
Visits will include:
* Medical history and physical exam
* Blood tests or saliva sample
* Possible skin biopsy: A small piece of the participant s skin will be removed.
* Bone marrow aspiration or biopsy: The participant s bone marrow will be removed by needle from a large bone such as the hip bone.
* Possible apheresis: Blood will be removed from the body and certain blood cells will be taken out. The rest of the blood is returned to the body.
Between visits, participants with a suspected or confirmed variant will keep a diary of disease symptoms and signs.
Samples from all participants may be used for genetic testing