Juvenile polyposis syndrome
Encyclopedia
Juvenile polyposis syndrome is a syndrome characterized by the appearance of multiple polyps in the gastrointestinal tract, usually in a child, adolescent or young adult. Polyps refers to a growth arising from the lumen
of the colon
or stomach. While the majority of the polyps found in Juvenile Polyposis Syndrome are non-neoplastic, 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
criteria for diagnosis of juvenile polyposis syndrome are one of either:
Affected individuals may present with rectal bleeding, abdominal pain, diarrhea or anemia. On colonoscopy
or sigmoidoscopy
polyps that vary in shape or size are present. The polyps can be sessile or pedunculated hamartomatous polyps.
Most juvenile polyps are benign, however, malignancy can occur. Lifetime risk of developing cancers of the gastro-intestinal tract range from 9% to 50%.
Two gene
s associated with Juvenile Polyposis Syndrome are BMPR1A
and SMAD4 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
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 harmatoma tumour syndrome.
. But multiple polyps (>5), polyposis syndrome, of the colon carries a 10% risk of developing into cancer. This is mainly because of juvenile polyps developing adenomatous tissue.
. Their siblings may also need to be screened regularly. Malignant
transformation of polyps requires surgical colectomy
.
Lumen (anatomy)
A lumen in biology is the inside space of a tubular structure, such as an artery or intestine...
of the colon
Colon (anatomy)
The colon is the last part of the digestive system in most vertebrates; it extracts water and salt from solid wastes before they are eliminated from the body, and is the site in which flora-aided fermentation of unabsorbed material occurs. Unlike the small intestine, the colon does not play a...
or stomach. While the majority of the polyps found in Juvenile Polyposis Syndrome are non-neoplastic, 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
World Health Organization
The World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health. Established on 7 April 1948, with headquarters in Geneva, Switzerland, the agency inherited the mandate and resources of its predecessor, the Health...
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 tractGastrointestinal tractThe human gastrointestinal tract refers to the stomach and intestine, and sometimes to all the structures from the mouth to the anus. ....
; or - Any number of juvenile polyps in a person with a family history of juvenile polyposis.
Presentation
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 age of onset.Affected individuals may present with rectal bleeding, abdominal pain, diarrhea or anemia. On colonoscopy
Colonoscopy
Colonoscopy is the endoscopic examination of the large bowel and the distal part of the small bowel with a CCD camera or a fiber optic camera on a flexible tube passed through the anus. It may provide a visual diagnosis and grants the opportunity for biopsy or removal of suspected...
or sigmoidoscopy
Sigmoidoscopy
Sigmoidoscopy From Greek Sigma - eidos - scopy, to look inside an s-like object, is the minimally invasive medical examination of the large intestine from the rectum through the last part of the colon. There are two types of sigmoidoscopy, flexible sigmoidoscopy, which uses a flexible endoscope,...
polyps that vary in shape or size are present. The polyps can be sessile or pedunculated hamartomatous polyps.
Most juvenile polyps are benign, however, malignancy can occur. Lifetime risk of developing cancers of the gastro-intestinal tract range from 9% to 50%.
Genetics
Juvenile Polyposis Syndrome can occur sporadically in families or be inherited in an autosomal dominant manner.Two gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
s associated with Juvenile Polyposis Syndrome are BMPR1A
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 .- Function :...
and SMAD4 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
Mutation
In molecular biology and genetics, mutations are changes in a genomic sequence: the DNA sequence of a cell's genome or the DNA or RNA sequence of a virus. They can be defined as sudden and spontaneous changes in the cell. Mutations are caused by radiation, viruses, transposons and mutagenic...
s in the gene PTEN
PTEN (gene)
Phosphatase and tensin homolog is a protein that, in humans, is encoded by the PTEN gene. Mutations of this gene are a step in the development of many cancers....
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
Cowden syndrome is a rare autosomal dominant inherited disorder characterized by multiple tumor-like growths called hamartomas and an increased risk of certain forms of cancer....
or other phenotypes of the PTEN harmatoma tumour syndrome.
Prognosis
Solitary polyps have no significant risk of cancerCancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
. But multiple polyps (>5), polyposis syndrome, of the colon carries a 10% risk of developing into cancer. This is mainly because of juvenile polyps developing adenomatous tissue.
Screening and treatment
People with juvenile polyps they require yearly upper and lower endoscopies with polyp excision and cytologyCell biology
Cell biology is a scientific discipline that studies cells – their physiological properties, their structure, the organelles they contain, interactions with their environment, their life cycle, division and death. This is done both on a microscopic and molecular level...
. Their siblings may also need to be screened regularly. Malignant
Malignant
Malignancy is the tendency of a medical condition, especially tumors, to become progressively worse and to potentially result in death. Malignancy in cancers is characterized by anaplasia, invasiveness, and metastasis...
transformation of polyps requires surgical colectomy
Colectomy
Colectomy consists of the surgical resection of any extent of the large intestine .-History:Sir William Arbuthnot-Lane was one of the early proponents of the usefulness of total colectomies, although his overuse of the procedure called the wisdom of the surgery into question.-Indications:Some of...
.
External links
- http://www.peutz-jeghers.com/jp/default.htm
- http://www.mtsinai.on.ca/familialgicancer/Diseases/JP/default.htm
- GeneReview/NIH/UW entry on Juvenile Polyposis Syndrome
- http://www.polyposisregistry.org.uk/