Variants in the TLA1A coding gene TNFSF15 has been associated with IBD, and particularly CD-associated TNFSF15 genetic variations has been reported to contribute to enhanced induction of TL1A, resulting in severe, chronic mucosal inflammation, denoting fibrostenosis susceptibility in these patients (55, 56). The gene discussed is TNFSF15; the disease is Cowden disease.