NFKB1 and pyoderma gangrenosum: Thereafter, several case reports have described cutaneous inflammatory reactions including pyoderma gangrenosum (PG),16,17,18 sterile inflammation and delayed wound healing,19 or recurrent necrotizing cellulitis20 in patients with truncating mutations of NFKB1. Since our previous report,15 we have encountered five additional unrelated families from four different countries in which patients with monoallelic truncating variants of NFKB1 presented with severe NF or other severe soft tissue inflammation.