Wiskott-Aldrich Syndrome Protein: WASP protein is mutated in WISKOTT-ALDRICH SYNDROME and is expressed primarily in hematopoietic cells. It is the founding member of the WASP protein family and interacts with CDC42 PROTEIN to help regulate ACTIN polymerization.Wiskott-Aldrich Syndrome Protein Family: A family of microfilament proteins whose name derives from the fact that mutations in members of this protein family have been associated with WISKOTT-ALDRICH SYNDROME. They are involved in ACTIN polymerization and contain a polyproline-rich region that binds to PROFILIN, and a verprolin homology domain that binds G-ACTIN.Wiskott-Aldrich Syndrome: A rare, X-linked immunodeficiency syndrome characterized by ECZEMA; LYMPHOPENIA; and, recurrent pyogenic infection. It is seen exclusively in young boys. Typically, IMMUNOGLOBULIN M levels are low and IMMUNOGLOBULIN A and IMMUNOGLOBULIN E levels are elevated. Lymphoreticular malignancies are common.Wiskott-Aldrich Syndrome Protein, Neuronal: A member of the Wiskott-Aldrich syndrome protein family that is found at high levels in NERVE CELLS. It interacts with GRB2 ADAPTOR PROTEIN and with CDC42 PROTEIN.Syndrome: A characteristic symptom complex.