ISOLATION OF A NOVEL GENE MUTATED IN WISKOTT-ALDRICH SYNDROME

Wiskott-Aldrich syndrome (WAS) is an X-linked recessive immunodeficien cy characterized by eczema, thrombocytopenia, and recurrent infections . Linkage studies have placed the gene at Xp11.22-p11.23. We have isol ated from this interval a novel gene, WASP, which is expressed in lymp hocytes, spleen, and thymus. The gene is not expressed in two unrelate d WAS patients, one of whom has a single base deletion that produces a frame shift and premature termination of translation. Two additional patients have been identified with point mutations that change the sam e arginine residue to either a histidine or a leucine. WASP encodes a 501 amino acid proline-rich protein that is likely to be a key regulat or of lymphocyte and platelet function.