For example, NOD2 – the first CD susceptibility gene to be discovered2, 3, 4 – was principally thought to be an intracellular pattern recognition receptor involved in defence against bacteria,32 but it was subsequently shown that NOD2 also interacts with ATG16L1 during autophagosome formation.33, 34, 35. The gene discussed is ATG16L1; the disease is Cowden disease.