BMPR1A and acquired polycythemia vera: In three other patients, no PV or variant(s) of unknown significance were detected despite meticulous analysis of polyposis-associated genes, including BMPR1A, SMAD4, and PTEN. One of these patients had six juvenile polyps removed at 11–13 years of age and had not had any other polyps detected since (last follow-up at 25 years of age).