NFKB1 and hypohidrotic ectodermal dysplasia: In addition, mice deficient for nuclear factor-κB (NF-κB) activity also showed a phenotype identical to HED, leading researchers to realize that EDA/EDAR sends signals through the NF-κB pathway during skin appendage development (Doffinger et al., 2001; Kumar et al., 2001; Schmidt-Ullrich et al., 2001).