Ectodermal dysplasia with nail dystrophy, sparse hair, and alopecia, as described in a third of patients with AD p52LOF/IκBδGOF and in all four patients with AR partial IKK-α deficiency, was not reported in the seven NIK-deficient patients, and subtle manifestations were found in only one of the nine patients with AR RelB deficiency (P2, sparse body hair during childhood) (8, 15, 18, 19). Here, CHUK is linked to ectodermal dysplasia syndrome.