Juvenile polyposis syndrome (JPS) [MIM:174900]: Autosomal dominant gastrointestinal hamartomatous polyposis syndrome in which patients are at risk for developing gastrointestinal cancers. The lesions are typified by a smooth histological appearance, predominant stroma, cystic spaces and lack of a smooth muscle core. Multiple juvenile polyps usually occur in a number of Mendelian disorders. Sometimes, these polyps occur without associated features as in JPS; here, polyps tend to occur in the large bowel and are associated with an increased risk of colon and other gastrointestinal cancers. {ECO:0000269|PubMed:11536076, ECO:0000269|PubMed:12136244, ECO:0000269|PubMed:12417513, ECO:0000269|PubMed:12630959}. Note=The disease is caused by mutations affecting the gene represented in this entry.; Polyposis syndrome, mixed hereditary 2 (HMPS2) [MIM:610069]: A disease is characterized by atypical juvenile polyps, colonic adenomas, and colorectal carcinomas. Note=The disease is caused by mutations affecting the gene represented in this entry.; Note=A microdeletion of chromosome 10q23 involving BMPR1A and PTEN is a cause of chromosome 10q23 deletion syndrome, which shows overlapping features of the following three disorders: Bannayan-Zonana syndrome, Cowden disease and juvenile polyposis syndrome. {ECO:0000269|PubMed:11381269, ECO:0000269|PubMed:16525031}.