We can hypothesize that in IBD patients, the TNF-α rs179996 rare C allele, particularly in the homozygote genotype, may cause an increase of TNF-α expression and a reduction of response to anti-TNF-α therapy, thus predisposing to the paradoxical adverse reaction in patients treated with anti-TNF-α drugs, especially adalimumab [38,46]. This evidence concerns the gene TNF and inflammatory bowel disease.