Juvenile polyposis syndrome is an inherited condition that is characterized by the development of hamartomatous polyps throughout the digestive tract. The term juvenile polyposis refers to the type of polyp (juvenile polyp) that is found on pathology examination rather than the age at which people are diagnosed with JPS. The number of polyps a person has during his or her lifetime can range from none to hundreds and polyp development can begin at any time in life from early infancy to the geriatric years.
Most juvenile polyps are benign (noncancerous), but on occasion these polyps can become cancerous with JPS families having an increased risk of colorectal, stomach, small intestine, or pancreatic cancer. Genetic mistakes in two genes (BMPR1A and SMAD4) have been linked to roughly half of the families with this syndrome meaning other causative genes remain to be identified. This syndrome is known for its unpredictability. Although mutations in the JPS genes predispose individuals to polyp development and colon cancer, not all people who carry these mutations will develop colon cancer or even polyps. For these reasons, gene testing is the only reliable way to know who does and does not have this disease in JPS families with a known gene mutation.
Careful follow-up, including upper and lower endoscopy (colonoscopy), can remove polyps for examination and help to reduce the risk of cancer from this disease.