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What do you know about Juvenile Polyposis Syndrome? Day 3 Hereditary Cancer Awareness Week

Courtesy of Dr, Sura Al Rawabdeh, MD from the presentation Small and Large Intestinal pathology, part 3 - April 13 2022

Thanks to NASPGHAN for sharing their knowledge of Juvenile Polyposis Syndrome.

The name “Juvenile Polyposis Syndrome” can be misleading, as individuals of all ages are affected with this condition. The term “juvenile” instead refers to the type of colon polyp that is characteristic of Juvenile Polyposis Syndrome (JPS).

However, individuals with JPS do typically develop colon polyps in childhood and adolescence. The number of polyps that a person may develop varies, even amongst people of the same family, with some affected individuals developing only a few polyps and others developing hundreds. Polyps are most often found in the colon and rectum, though they can also grow in the stomach and small intestine. The majority of polyps are benign, but there is a chance that some may become cancerous over time. The estimated lifetime risk to develop colon cancer is about 50%, and there is also an association with stomach and small intestine cancer. About 15% of people with JPS will have non-cancerous findings at birth, such as intestinal twisting, cleft palate, extra fingers and/or toes, and growth abnormalities of the brain, heart, genitalia, or urinary tract. There are three type of JPS:

  1. juvenile polyposis of infancy, which is the most severe and is apparent in infants,

  2. generalized juvenile polyposis, which is the most common and in which polyps grow throughout the GI tract, and

  3. juvenile polyposis coli, in which polyps grow only in the colon.

JPS affects approximately 1 in 100,000 individuals globally, and is caused by mutations in two different genes, BMPR1A and SMAD4. However, in about 50% of cases no genetic mutation is identified. In these instances, the diagnosis is made on clinical findings of juvenile polyps alone. In many cases (50-75%) there is a family history of JPS, but there is also a significant portion of cases (25-50%) in which the mutation is new in the individual and there is no family history of JPS symptoms. People with SMAD4 mutations can also have a bleeding condition called hereditary hemorrhagic telangiectasia (HHT). Therefore, they require surveillance for anemia and bleeding in addition to colonoscopies and upper endoscopies to screen for polyps. Browse the links below to learn more about Juvenile Polyposis Syndrome:

To find an inherited GI Cancer Genetics Clinic near you, check out the “Find a Clinic” page on the CGA-IGC website:

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