Based on the AND-1 cell line31 and using ZFNs targeted to the WAS locus,41 we have developed two pluripotent cell line clones (AND-1_WASKO_c1.1 and AND-1_WASKO_c1.2) with a complete absence of WASp to mimic WAS patients with a severe phenotype. The gene discussed is WAS; the disease is Wiskott-Aldrich syndrome.