Its role is to regulate the flow of bile and pancreatic juices into the duodenum as well as to prevent the reflux of the duodenal contents into the pancreatobiliary system.[1] The abnormalities of SO contractility (sphincter of Oddi dysfunction: SOD) may be related to either the biliary or the pancreatic segments of the sphincter or both.[2] SOD refers to structural or functional disorders involving the biliary sphincter that may result in the impedance of bile and pancreatic juice flow. This evidence concerns the gene SOD1 and biliary dyskinesia.