Bile acid malabsorption is also common in inflammatory bowel diseases (primarily Crohn disease involving the terminal ileum), after bariatric surgery (primarily Roux-en-Y gastric bypass), and as a side effect of some drugs approved by the U.S. Food and Drug Administration (e.g. lenalidomide); these drugs inhibit the function of ASBT, the key intestinal bile acid transporter [13, 33]. The gene discussed is SLC10A2; the disease is inflammatory bowel disease.