Wiskott-Aldrich syndrome, an X-linked immuno-deficiency disorder caused by mutations of Wiskott-Aldrich syndrome protein (WASP) gene, is characterized by thrombocytopenia, recurrent infections, and eczema. Most of the cases of Wiskott-Aldrich syndrome, reported previously in Korea, were diagnosed entirely based on clinical symptoms and through serum levels of IgM, IgA, and IgE. A deletion of 1316 G in exon 10 of x-chromosome was detected through deoxyribonucleic acid (DNA) gene sequencing in a Wiskott-Aldrich Syndrome patient, who later on was successfully treated with unrelated allogeneic cord blood transplantation.