Mutation in WASp gene; leukocytes and platelets unable to reorganize actin cytoskeleton → defective antigen presentation

- X-linked recessive

- Eczema- Thrombocytopenia- Recurrent (pyogenic) infections- ↑ risk of autoimmune disease and hematological malignancies

- ↓ to normal IgG, IgM- ↑ IgE, IgA- Thrombocytopenia with small platelets