This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Juvenile polyposis syndrome (JPS) is a disorder characterized by having a susceptibility to developing hamartomatous polyps in the gastrointestinal (GI) tract. A hamartomatous polyp is a benign (noncancerous) tumor-like malformation made up of an abnormal mixture of cells and tissues. In JPS, these polyps can occur in the stomach, small intestine, colon, and rectum. The term “juvenile” refers to the type of polyp and not the age at which the polyps develop.
Most people with JPS have some polyps by the age of age 20. The number of polyps in affected people vary. While some people may have only four or five polyps over their lifetime, others (even in the same family) may have more than 100. If the polyps are left untreated, they can result in bleeding and anemia. Most juvenile polyps are benign, although over time they can become cancerous. In families with JPS, the risk for developing a GI cancer ranges from 9% to 50%. Most of this risk is due to colon cancer. The incidence of colorectal cancer in people with JPS is 17%-22% by the age of 35 and as high as 68% by the age of 60. Cancers of the stomach, upper GI tract, and pancreas have also been observed. To date, mutations in two genes are known to cause JPS: BMPR1A and SMAD4.
Management of JPS includes routine colonoscopy with removal of any polyps to reduce the risk of bleeding, intestinal obstruction, and colon cancer. When the number of polyps is large, removal of all or part of the colon or stomach may become needed. Additional screening can include upper endoscopy, complete blood count, and monitoring for symptoms such as rectal bleeding and/or anemia abdominal pain, constipation, diarrhea, or change in stool size, shape, and/or color.
For more information, visit GARD.