Genetic DisordersThe Genetics and Functional Basis of Inherited Platelet, White Blood Cell, Red Blood Cell, and Blood Clotting Disorders.

Inclusion Criteria:

A. Normal Healthy Volunteers:

1. Normal healthy volunteers
2. 18 years of age or older
3. Either sex
4. Any ethnic background.

B. Patients with Glanzmann thrombasthenia or their relatives, inherited qualitative and/or quantitative platelet disorders, inherited disorders of white blood cells, inherited disorders of coagulation (including von Willebrand disease):

1. Adults and children
2. Either sex
3. Any ethnic background

Exclusion Criteria:

A. Normal Healthy Volunteers:

1. For studies of platelets that may be affected by anti-platelet therapy, ingestion of aspirin or similar medication in the past week.
2. Having given blood in the last 8 weeks such that the current donation would exceed a total of 250 ml for the 8 week period.
3. Having given blood in the past week such that this donation would result in more than 2 donations in one week.

B. Patients with Glanzmann thrombasthenia or their relatives, inherited qualitative and/or quantitative platelet disorders, inherited disorders of white blood cells, inherited disorders of coagulation (including von Willebrand disease).

1. For studies of platelets that may be affected by antiplatelet therapy, ingestion of aspirin or similar medication in the past week
2. If the patient is known to have a hematocrit ≥25 (assay performed in past 3 months), the same blood drawing criteria as in A, with the addition that for children less than 18 years of age, the maximum amount of blood allowed to be donated in an 8 week period is the lesser of 50 ml or 3 ml/kg.
3. If the patient has a hematocrit <25 or if the hematocrit is unknown, the blood drawing limit is the lesser of 20 ml or 1 ml/kg in any 8 week period.