NFKB1 and incontinentia pigmenti: We and others have shown that hypomorphic mutations in NEMO that lead to impairment, but not abolition of NF-κB signalling, are associated with the less clinically severe anhydrotic ectodermal dysplasia syndrome, whereas amorphic NEMO mutations that completely abolish NF-κB activation are associated with IP in females and in utero lethality in males16.