Juvenile Polyposis Syndrome (JPS) is a condition which is characterized by the presence of hamartomatous polyps in the digestive tract. Hamartomas are non-cancerous masses of normal tissue that build up in the intestines or other places.

These masses are called polyps if they develop inside a body structure, such as the intestines. The term juvenile polyposis refers to the type of polyp (juvenile polyp) that is found after examination of the polyp under a microscope, rather than the age at which people are diagnosed with Juvenile Polyposis Syndrome (JPS).

Polyps may frequently develop in a person with Juvenile Polyposis Syndrome by age 20. The number of polyps a person has during his or her lifetime can range from around five to more than 100.

Most juvenile polyps are benign (non-cancerous), but there is an increased risk of cancer of the digestive tract in families with Juvenile Polyposis Syndrome (JPS).

Juvenile Polyposis Syndrome (JPS) is suspected when a person’s symptoms and history that fall into one of the following categories:

• More than five juvenile polyps of the colon and/or rectum
• There are multiple juvenile polyps throughout the digestive tract (stomach, small intestine, colon, and rectum)
• Any number of juvenile polyps and a family history of juvenile polyps

What causes Juvenile Polyposis Syndrome (JPS)?

Juvenile Polyposis Syndrome (JPS) is a genetic condition. This means that the risk for polyps and cancer can be passed from generation to generation in a family. Two genes have been linked to JPS. They are called BMPR1A and SMAD4.

A mutation (alteration) in either the BMPR1A gene or the SMAD4 gene makes a person more likely to develop juvenile polyps and cancer of the digestive tract over his or her lifetime.

Not all families that have Juvenile Polyposis Syndrome (JPS) will have mutations in BMPR1A or SMAD4. Other genes are being studied regarding their link to Juvenile Polyposis Syndrome (JPS).

How is Juvenile Polyposis Syndrome (JPS) diagnosed?

A diagnosis of Juvenile Polyposis Syndrome (JPS) is assumed if a person’s symptoms and history fit one of the three categories listed above. People who have Juvenile Polyposis Syndrome (JPS) can have a blood test to look for a mutation in the BMPR1A gene or the SMAD4 gene.

If a specific gene mutation is present, other family members will be diagnosed with Juvenile Polyposis Syndrome (JPS) if they are tested and have the same gene mutation.

It appears likely that there are other genes associated with JPS that have not yet been identified, so a blood test result that comes back as “negative” (meaning a gene mutation cannot be found) does not mean that a person does not have Juvenile Polyposis Syndrome (JPS).

Therefore, meeting with a health professional who specializes in genetics, such as a genetic counselor or medical geneticist, is recommended for people who have a family history or symptoms that suggest Juvenile Polyposis Syndrome (JPS).

What is the estimated cancer risk associated with Juvenile Polyposis Syndrome (JPS)?

People with Juvenile Polyposis Syndrome (JPS) are considered to be at increased risk for colorectal, stomach, small intestine, and pancreatic cancers. The total estimated cancer risk associated with JPS is 9% to 50%, but the risks for each specific type of cancer have not been determined.

What are the screening options for Juvenile Polyposis Syndrome (JPS)?

It is important to discuss with your doctor the following screening options, as each individual is different:

• A complete blood count (CBC, a blood test), colonoscopy, and upper endoscopy should be done at age 15 (or earlier if there are symptoms)
• If tests are normal they should be repeated every three years.
• If polyps are found, they should be removed, and screening should be done every year.
• Individuals who develop large numbers of polyps may need to have surgery to remove part of the colon or stomach.

Diagnosing options may change over time as new technologies are developed and more is learned about Juvenile Polyposis Syndrome (JPS). It is important to talk with the doctor about appropriate screening tests.