Mutations in further ED candidate genes TNF receptor associated factor 6 (TRAF6), Inhibitor Of Nuclear Factor Kappa B Kinase Subunit Gamma (IKBKG, formerly NEMO), NFκB inhibitor α (NFKBIA) and NFκBs also cause immunodeficiency (Cui and Schlessinger 2006) but variants with effects on protein function were not identified in these candidates. Here, IKBKG is linked to immunodeficiency disease.