A schematic illustration of WASP representing the 12 exons and the major functional domains. The mutations of WASP listed in Table 1 are visualized according to their location in the exons and the exon/intron junctions. Each symbol represents a single family with a WASP mutation. Missense mutations are located mostly in exons 1 to 4; deletions and insertions are distributed throughout the WASP gene, and splice site mutations are found predominantly in introns 6, 8, 9, and 10. PH indicates pleckstrin hemology; WH1, WAS homology 1; GBD, GTPase binding domain; VD, verprolin homology domain; and CD, cofilin homology domain.