FAP and carcinoma of duodenum: PIGA was not identified as a significantly and recurrently mutated gene in 12 sporadic duodenal adenocarcinomas analyzed by Yuan and colleagues (17), although a different study of 21 sporadic duodenal carcinomas revealed one PIGA variant (p.Q58X; ref. 18), indicating that mutation of PIGA may also be involved in duodenal carcinoma development outside of the context of FAP and MAP.