Juvenile polyposis syndrome is an autosomal dominant genetic condition characterized by the appearance of multiple juvenile polyps in the gastrointestinal tract. Polyps are abnormal growths arising from a

mucous membrane A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It i ...

. These usually begin appearing before age 20, but the term ''juvenile'' refers to the type of polyp (i.e benign hamartoma, as opposed to adenoma for example), not to the age of the affected person. While the majority of the polyps found in juvenile polyposis syndrome are non-

neoplastic A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

, hamartomatous, self-limiting and benign, there is an increased risk of adenocarcinoma. Solitary juvenile polyps most commonly occur in the rectum and present with rectal bleeding. The

World Health Organization The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level of ...

criteria for diagnosis of juvenile polyposis syndrome are one of either: # More than five juvenile polyps in the colon or rectum; or # Juvenile polyps throughout the gastrointestinal tract; or # Any number of juvenile polyps in a person with a family history of juvenile polyposis.

Signs and symptoms

Age of onset is variable. The term 'juvenile' in the title of juvenile polyposis syndrome refers to the histological type of the polyps rather than the age of onset. Affected individuals may present with rectal bleeding, abdominal pain, diarrhea or anemia. On colonoscopy or

sigmoidoscopy Sigmoidoscopy (from the Greek term for letter " s/ς" + "eidos" + "scopy": namely, to look inside an "s"/"ς"-like object) is the minimally invasive medical examination of the large intestine from the rectum through to the nearest part of the co ...

polyps that vary in shape or size are present. The polyps can be sessile or pedunculated hamartomatous polyps.

Genetics

Juvenile polyposis syndrome can occur sporadically in families or be inherited in an autosomal dominant manner. Two

gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...

s associated with juvenile polyposis syndrome are

BMPR1A The bone morphogenetic protein receptor, type IA also known as BMPR1A is a protein which in humans is encoded by the ''BMPR1A'' gene. BMPR1A has also been designated as CD292 (cluster of differentiation 292). Function The bone morphogenetic pr ...

and

SMAD4 SMAD4, also called SMAD family member 4, Mothers against decapentaplegic homolog 4, or DPC4 (Deleted in Pancreatic Cancer-4) is a highly conserved protein present in all metazoans. It belongs to the SMAD family of transcription factor proteins, ...

. Gene testing may be useful when trying to ascertain which non-symptomatic family members may be at risk of developing polyps, however having a known familial mutation would be unlikely to change the course of treatment. A known mutation may also be of use for affected individuals when they decide to start a family as it allows them reproductive choices. While

mutation In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA replication, DNA or viral repl ...

s in the gene PTEN were also thought to have caused juvenile polyposis syndrome, it is now thought that mutations in this gene cause a similar clinical picture to juvenile polyposis syndrome but are actually affected with Cowden syndrome or other phenotypes of the PTEN hamartoma tumor syndrome.

Screening

People with juvenile polyps may require yearly upper and lower endoscopies with polyp excision and

cytology Cell biology (also cellular biology or cytology) is a branch of biology that studies the structure, function, and behavior of cells. All living organisms are made of cells. A cell is the basic unit of life that is responsible for the living an ...

. Their siblings may also need to be screened regularly.

Treatment

Malignant Malignancy () is the tendency of a medical condition to become progressively worse. Malignancy is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous ''benign'' tumor in that a malignancy is not s ...

transformation of polyps requires surgical

colectomy Colectomy ('' col-'' + '' -ectomy'') is bowel resection of the large bowel ( colon). It consists of the surgical removal of any extent of the colon, usually segmental resection (partial colectomy). In extreme cases where the entire large intest ...

Prognosis

Most juvenile polyps are benign; however,

malignancy Malignancy () is the tendency of a medical condition to become progressively worse. Malignancy is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous ''benign'' tumor in that a malignancy is not s ...

can occur. The cumulative lifetime risk of colorectal cancer is 39% in patients with juvenile polyposis syndrome.

References

External links

{{Cell surface receptor deficiencies Cell surface receptor deficiencies Pediatric cancers Hereditary cancers Gastrointestinal cancer Syndromes affecting the gastrointestinal tract