{"id":27113,"date":"2024-05-26T12:43:33","date_gmt":"2024-05-26T10:43:33","guid":{"rendered":"https:\/\/www.krebs-praedisposition.de\/?post_type=kompendium&p=27113"},"modified":"2025-08-26T11:22:26","modified_gmt":"2025-08-26T09:22:26","slug":"juvenile-polyposis-syndrome","status":"publish","type":"kompendium","link":"https:\/\/www.krebs-praedisposition.de\/en\/kompendium\/juvenile-polyposis-syndrome\/","title":{"rendered":"Juvenile Polyposis Syndrome"},"content":{"rendered":"

Juvenile Polyposis Syndrome \u2013\u00a0Definition<\/h2><\/div>
<\/div><\/div><\/div><\/div>

Juvenile polyposis syndrome (JPS, OMIM #174900) is a genetic disease caused by heterozygous pathogenic variants in the BMPR1A<\/em> or SMAD4<\/em> gene. It is characterized by the occurrence of juvenile hamartomatous gastrointestinal polyps and a predisposition to gastrointestinal tumors. In addition, pathogenic variants in the SMAD4<\/em> gene are also associated with hereditary hemorrhagic telangiectasia (HHT).<\/p>\n<\/div>

Synonyms:<\/p>\n<\/div><\/div><\/div>

–<\/p>\n<\/div><\/div><\/div><\/div>

<\/div><\/div>

Genes:<\/p>\n<\/div><\/div><\/div>

BMPR1A<\/i><\/p>\n

SMAD4<\/i><\/p>\n<\/div><\/div><\/div><\/div>

<\/div><\/div>

Gene \u00adproducts:<\/p>\n<\/div><\/div><\/div>

Bone morphogenetic protein receptor type-1A (BMPR1A)<\/p>\n

Mothers against decapentaplegic homolog 4 (SMAD4)<\/p>\n<\/div><\/div><\/div><\/div>

<\/div><\/div>

Function:<\/p>\n<\/div><\/div><\/div>

Tumor suppressors, associated with the TGF-\u03b2 signaling pathway<\/p>\n<\/div><\/div><\/div><\/div>

<\/div><\/div>

Pattern of inheritance:<\/p>\n<\/div><\/div><\/div>

Autosomal dominant, around 67% de novo<\/em> mutations<\/p>\n<\/div><\/div><\/div><\/div>

<\/div><\/div>

Prevalence:<\/p>\n<\/div><\/div><\/div>

The incidence is between 1:16.000 and 1:100.000.<\/p>\n<\/div><\/div><\/div><\/div>

<\/div><\/div>

Genotype-phenotype correlation:<\/p>\n<\/div><\/div><\/div>

Pathogenic variants in SMAD4<\/em> are associated with hereditary hemorrhagic telangiectasia (HHT, Osler-Weber-Rendu disease).<\/p>\n

Pathogenic variants in SMAD4<\/em>\u00a0go hand-in-hand with a greater risk of polyps in the upper GI tract, whereby this phenotype presumably has a more aggressive progression and is associated with significant polyposis and a greater risk of gastric carcinomas.<\/p>\n

Patients with a pathogenic SMAD4<\/em> or BMPR1A<\/em> variant are more likely to have > 10 polyps in the lower GI tract and a positive family history of gastrointestinal malignancies than patients without evidence of a pathogenic variant.<\/p>\n<\/div><\/div><\/div><\/div>

<\/div><\/div>

Penetrance:<\/p>\n<\/div><\/div><\/div>

97% of patients develop colonic polyps, 68% gastric polyps, and 76% exhibit signs of HHT.
\nThe cumulative lifetime risk of a colorectal carcinoma is 39%. The risk of a gastric carcinoma is 21% in patients with gastric polyps.<\/p>\n<\/div><\/div><\/div><\/div><\/div><\/div>

<\/div>
<\/div><\/div><\/div><\/div><\/div><\/div>

Overview of the Chapters on This Page:<\/h4><\/div><\/div><\/div>