FADD and colitis: For example, the fatal enteritis and colitis that develop after simultaneous deletion of A20 and ABIN-1 in IECs rivals the severity reported for intestinal epithelial deletion of NEMO (44, 78), FADD (45, 79), CASP8 (45, 71), RIPK1 (42, 80), ATG16L1 (8), or combined deletion of XBP1 and ATG16L1 (7).