NOD2

About NOD2

NOD2 on chromosome 16q12.1 encodes an intracellular pattern recognition receptor that detects muramyl dipeptide, a fragment of the peptidoglycan found in bacterial cell walls, and activates inflammatory and antimicrobial responses, including in Paneth cells of the small intestine. In 2001 NOD2, then also known as CARD15, became the first susceptibility gene identified for Crohn disease. Three common variants that reduce its function are associated with an increased risk of Crohn disease, particularly disease of the ileum, in people of European ancestry, though they are much less common in East Asian populations and most carriers never develop the disease. In contrast, gain of function variants in NOD2 cause Blau syndrome, a rare autosomal dominant inflammatory condition characterized by granulomatous arthritis, skin rash, and uveitis in childhood. NOD2 illustrates how variants in the same gene can have opposite effects on disease.