Question: A 20-year-old man presented to our clinic with a 3-year history of intermittent hematochezia, in addition to developmental delay. Laboratory analysis and physical examination were otherwise normal. Colonoscopy to investigate the cause of hematochezia revealed >100 tubular, tubulovillous, and villous adenomas throughout the colon, up to 2 cm in size (Figure A). Restorative proctocolectomy was performed and numerous polyps were found, but no evidence of invasive carcinoma was identified. The parents and the patient’s sibling were phenotypically normal, with no developmental delay and no family history of gastrointestinal cancer.