NFKB1 and immunodeficiency disease: Mutations within a regulatory subunit of the NFkB pathway, IKK-gamma/NF-kappa-B essential modulator (NEMO), are known to cause two distinct X-linked forms of ectodermal dysplasia: X-linked dominant familial incontinentia pigmenti (IP), which is typically fatal prenatally in males; and X-linked recessive disorder with rare combination of HED and immunodeficiency (HED-ID), in which incomplete loss of NEMO function leads to impaired immune response with recurrent bacterial and viral infections in addition to HED [2, 17, 21, 30, 46, 50, 59].