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Juvenile Polyposis Syndrome

Last updated Oct. 18, 2018

Approved by: Maulik P. Purohit MD, MPH

Juvenile Polyposis Syndrome (JPS) is a disorder characterized by multiple hamartomatous benign growths or polyps, usually in large intestines. Hamartomas arise as a result of disorganized growth of cells.

What are the other Names for this Condition? (Also known as/Synonyms)

  • BMPR1A-Related Juvenile Polyposis
  • Juvenile Intestinal Polyposis (JIP)
  • SMAD4-Related Juvenile Polyposis

What is Juvenile Polyposis Syndrome? (Definition/Background Information)

  • Juvenile Polyposis Syndrome (JPS) is a disorder characterized by multiple hamartomatous benign growths or polyps, usually in large intestines. Hamartomas arise as a result of disorganized growth of cells
  • The term “juvenile” (in Juvenile Polyposis Syndrome) refers to typical traits of the polyp (smooth, cystic, lobulated growths, with or without stalks), and not the age at which the syndrome manifests
  • Juvenile Polyposis Syndrome occurs worldwide, and can either be inherited or develop spontaneously. The familial type of JPS is caused by mutation(s) in the BMPR1A and SMAD4 genes
  • There are 3 variants of JPS:
    • Juvenile Polyposis of Infancy: It is the most severe form, which results in protein-losing enteropathy. The affected children lose valuable proteins through diarrhea, leading to growth retardation
    • Generalized Juvenile Polyposis: The characteristic trait of this variant is the presence of numerous polyps throughout the gastrointestinal tract of the affected individual during childhood
    • Juvenile Polyposis Coli: In this type, individuals develop polyps only in the colon, during childhood 
  • The signs and symptoms of JPS may include diarrhea, vomiting, rectal bleeding, and abdominal pain, among others. The potential complications include benign polyps turning cancerous, bleeding from the polyps, and protein-losing enteropathy in children
  • The treatment of Juvenile Polyposis Syndrome is undertaken symptomatically. Also, benign tumors may be surgically removed, while malignant tumors may be additionally treated using chemotherapy and/or radiation therapy
  • The prognosis of JPS is determined by the age of manifestation of the condition, with the infantile form being the most severe. If the polyps turn malignant, then the stage at which the cancer is diagnosed determines the outcome

Who gets Juvenile Polyposis Syndrome? (Age and Sex Distribution)

  • Juvenile Polyposis Syndrome is a rare congenital disorder that occurs worldwide, with a frequency between 1:16,000 to 1:100,000
  • Both males and females are equally affected by JPS
  • The age of symptom’ onset is variable, with polyps typically occurring in the second decade of life (between age 10 and 20)

What are the Risk Factors for Juvenile Polyposis Syndrome? (Predisposing Factors)

  • A majority of Juvenile Polyposis Syndrome cases are inherited, and therefore, having a family history of the disorder is a risk factor for developing JPS

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Juvenile Polyposis Syndrome? (Etiology)

Juvenile Polyposis Syndrome is caused by mutation(s) in the BMPR1A and SMAD4 genes.

  • Under normal circumstances, the BMPR1A gene codes for a protein known as the bone morphogenetic protein receptor 1A (or BMPR1A protein); the SMAD4 gene, codes for the SMAD4 protein
  • The BMPR1A protein binds to factors in a signaling pathway involved in cellular growth and proliferation. This event activates the SMAD4 protein, which transmits the extra-cellular signals to the nucleus. The two proteins function in a highly-coordinated manner to regulate cell division
  • When the BMPR1A and SMAD4 genes are mutated, the signaling pathway is affected and it functions in an un-regulated fashion, leading to increased growth and formation of polyps
  • The syndrome is inherited in an autosomal dominant manner. In this type of inheritance, the presence of a single defective copy of the causative gene in each cell of an individual is sufficient for the condition to manifest itself. An affected individual inherits the condition from an affected parent

In one-fourth of the affected individuals with no family history of JPS, the mutations in BMPR1A and SMAD4 genes are known to arise spontaneously.

What are the Signs and Symptoms of Juvenile Polyposis Syndrome?

The signs and symptoms of Juvenile Polyposis Syndrome may vary among the affected individuals in type and severity. Typically, the infantile form of JPS is considered the most severe. In many cases, an individual may be asymptomatic, till the polyps turn malignant. 

When symptoms are present, they may include the following:

  • Polyps in the stomach, small intestine, and predominantly, the large intestine. The number of polyps may range from 1 to over 100
  • Growth retardation in children
  • Rectal bleeding
  • Anemia
  • Diarrhea
  • Abdominal pain
  • Unexplained weight loss
  • Change in bowel habits
  • Loss of appetite
  • Weakness and fatigue
  • The presence of an abdominal mass
  • Prolapse of rectal polyps through anus

Approximately, 1 in every 6 affected Individuals may also have:

  • Twisted intestines (intestinal malrotation)
  • Cleft palate
  • Heart and/or brain abnormalities
  • Polydactyly (extra fingers or toes)
  • Abnormalities of the genitalia
  • Urinary tract abnormalities

How is Juvenile Polyposis Syndrome Diagnosed?

The criteria for diagnosis of Juvenile Polyposis Syndrome require one of the following 3 symptoms:

  • More than 5 juvenile polyps in the colon or rectum
  • Juvenile polyps throughout the gastrointestinal tract
  • Any number of juvenile polyps in an individual with a family history of JPS

The diagnosis of Juvenile Polyposis Syndrome is established by the following tests and exams:

  • A thorough physical examination and assessment of symptoms
  • Evaluating family history of polyps in the colon and colon cancer
  • Digital rectal examination
  • A blood test for complete blood cell (CBC) count
  • Carcino-embryonic antigen testing for colon cancers
  • Liver function tests: The result may be abnormal in metastatic colon cancer which has spread to the liver
  • Computed tomography (CT) scan of the abdomen and pelvis
  • Screening colonoscopy with biopsy to determine the type and size of polyps
  • Upper endoscopy (checking the upper part of the digestive tract for abnormalities)
  • Fecal occult blood test (FOBT) to detect blood in stool, which may be indicative of colon cancer. The presence of blood in stool does not mean that an individual has cancer; blood in stool, can occur due to non-cancerous causes as well
  • Double contrast barium enema to determine the presence of masses
  • Genetic testing to check for the gene mutation individuals carry

Note: If the results of colonoscopy and upper endoscopy are normal, the tests should be repeated every 3 years.

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis

What are the possible Complications of Juvenile Polyposis Syndrome?

Potential complications from Juvenile Polyposis Syndrome include:

  • A condition known as protein-losing enteropathy in children (loss of protein owing to diarrhea)
  • Growth retardation in children
  • Bleeding in polyps
  • The transformation of polyps to cancers

How is Juvenile Polyposis Syndrome Treated?

The treatments methods for Juvenile Polyposis Syndrome are geared toward relief from symptoms and reducing complications, since JPS is a genetic disorder and is incurable. The treatment options may include:

  • If there are few polyps, surgical removal of polyps
  • If cancer of colon develops, surgery, chemotherapy and/or radiation therapy, depending on the stage of cancer
  • Follow-up care and regular checkup visits may be recommended by the healthcare provider

How can Juvenile Polyposis Syndrome be Prevented?

  • At the present time, there are no methods or guidelines for the prevention of Juvenile Polyposis syndrome, since it is a genetic disorder
  • Genetic testing of the expecting parents (and related family members) and prenatal diagnosis (molecular testing of the fetus during pregnancy) may help in better understanding the risks during pregnancy
  • If there is a family history of JPS, then genetic counseling may help assess risks while planning for a child
  • At risk family members who have not yet been genetically tested are recommended to undergo annual colonoscopy
  • Regular medical screening at periodic intervals with screening colonoscopy/endoscopy, blood tests, and physical examinations are highly recommended, to monitor for malignant transformation of the polyps

Active research is currently being performed to explore the possibilities for treatment and prevention of inherited and acquired genetic disorders such as JPS.

What is the Prognosis of Juvenile Polyposis Syndrome? (Outcomes/Resolutions)

The prognosis of Juvenile Polyposis Syndrome is dependent upon the age of manifestation, severity of symptoms, and stage of the cancer, if polyps turn malignant.

  • Typically, the infantile form is the most severe form of JPS
  • In those with JPS, there is a 10-50% likelihood of developing cancer in the gastrointestinal tract. A majority of malignant tumors occur in the colon
  • Regular medical checkups can help detect cancers early, which when treated appropriately can increase life expectancy

Additional and Relevant Useful Information for Juvenile Polyposis Syndrome:

If Juvenile Polyposis syndrome occurs because of SMAD4 gene mutation, further tests, to check for hereditary hemorrhagic telangiectasia (HHT), are highly recommended. A high correlation is reported between JPS due to SMAD4 mutations and HHT.

What are some Useful Resources for Additional Information?

References and Information Sources used for the Article:

Helpful Peer-Reviewed Medical Articles:

Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: April 27, 2017
Last updated: Oct. 18, 2018