Juvenile polyposis syndrome (JPS; MIM 174900) is an autosomal dominant disorder that affects 1 in 100,000 individuals . JPS is characterized by the presence of hamartomatous polyps throughout the gastrointestinal (GI) tract and is associated with an increased risk for GI cancers [2,3]. Affected individuals may experience abdominal pain, diarrhea and rectal bleeding which can lead to anemia. Juvenile polyposis syndrome is diagnosed when an individual has any one of the following: (1) more than five juvenile polyps of the colon or rectum, (2) multiple juvenile polyps in the upper and lower gastrointestinal tract, or (3) any number of juvenile polyps and a family history of juvenile polyposis syndrome. JPS is caused by mutations in the gene encoding the mothers against decapentaplegic homolog 4 (SMAD4/MADH4) on chromosome 18q21.1 or in the gene encoding the bone morphogenic protein receptor-1A (BMPR1A) on chromosome 10q22.3 [4,5]. SMAD4, a tumor suppressor gene and BMPR1A are intracellular mediators of the transforming growth factor-beta (TGF-β) signaling pathway . SMAD4 and BMPR1A mutations cause JPS in approximately twenty percent of patients each [7,8]. Currently, it is unknown how juvenile polyps form as a consequence of germline SMAD4 or BMPR1A mutations or which additional unidentified genes are responsible for causing the other 60% of JPS.