Juvenile polyposis syndrome is an

autosomal dominant In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the Phenotype, effect of a different variant of the same gene on Homologous chromosome, the other copy of the chromosome. The firs ...

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 ...

. 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 Adenocarcinoma (; plural adenocarcinomas or adenocarcinomata ; AC) is a type of cancerous tumor that can occur in several parts of the body. It is defined as neoplasia of epithelial tissue that has glandular origin, glandular characteristics, or ...

. 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 list of specialized agencies of the United Nations, specialized agency of the United Nations which coordinates responses to international public health issues and emergencies. It is headquartered in Gen ...

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 The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the Digestion, digestive system that leads from the mouth to the anus. The tract is the largest of the body's systems, after the cardiovascula ...

; 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. Diagnosis is typically by way of

endoscopy An endoscopy is a procedure used in medicine to look inside the body. The endoscopy procedure uses an endoscope to examine the interior of a hollow organ or cavity of the body. Unlike many other medical imaging techniques, endoscopes are insert ...

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 ...

. On

colonoscopy Colonoscopy () or coloscopy () is a medical procedure involving the Endoscopy, endoscopic examination of the large bowel (colon) and the distal portion of the small bowel. This examination is performed using either a Charge-coupled device, CCD ...

sigmoidoscopy Sigmoidoscopy ("sigma", 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 th ...

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 has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...

s containing mutations 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 or viral replication, ...

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 Cowden syndrome (also known as Cowden's disease) is an autosomal dominant inherited condition characterized by benign overgrowths called hamartomas as well as an increased lifetime risk of breast, thyroid, uterine, and other cancers. It is also k ...

or other phenotypes of the PTEN hamartoma tumor syndrome. Mutations in ''SMAD4'' may be additionally associated with concomitant

hereditary hemorrhagic telangiectasia Hereditary hemorrhagic telangiectasia (HHT), also known as Osler–Weber–Rendu disease and Osler–Weber–Rendu syndrome, is a rare autosomal dominant genetic disorder that leads to abnormal blood vessel formation in the Human skin, skin, muco ...

Screening

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

. Their siblings may also need to be screened regularly.

Treatment

Malignant Malignancy () is the tendency of a medical condition to become progressively worse; the term is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous benign tumor, ''benign'' tumor in that a malig ...

transformation of polyps requires surgical

colectomy Colectomy (''wikt:colo-#Prefix, col-'' + ''wikt:-ectomy#Suffix, -ectomy'') is the surgical removal of any extent of the Large intestine#Structure, colon, the longest portion of the large bowel. Colectomy may be performed for prophylactic, curativ ...

Prognosis

Most juvenile polyps are benign; however,

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

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