DAVID syndrome families and NFKB2 gene structure with mutations. A-D, pedigrees showing genotypes of sequenced individuals. Symbols: Filled, immunodeficiency, ACTH deficiency, GH deficiency; lower half filled, immunodeficiency; lower half plus upper left quadrant filled, immunodeficiency, ACTH deficiency; open, unaffected or unknown. n.a. DNA and clinical information not available. +/+, no mutation at any of the three sites found in the families. E, structure of the NFκB2 protein (isoform A numbering), indicating the major functional domains, regulated phosphorylated serines 866 and 870, and sites of mutations reported here, by Chen, Liu, Lee, Lindsley et al, or at the orthologous site in the Lym1 mouse (Tucker et al). The vertical arrow above the domain cartoon indicates approximate site of proteolytic cleavage of p100, which releases the amino-terminal p52 active fragment. RHD, rel homology domain; ARDs, ankyrin repeat domains; DD, death domain; NRD, NIK response domain.