Anti-tumour necrosis factor [TNF] therapies remain the most effective treatment to induce and maintain remission in patients with Crohn’s disease.1,2 Successful treatment leads to mucosal healing, reduced surgeries, and improvements in quality of life.3 Unfortunately, anti-TNF treatment failure is common, with a quarter of patients experiencing primary non-response and one-third of initial responders losing response by the end of the first year.4 The gene discussed is TNF; the disease is Crohn disease.