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Juvenile Polyposis Syndrome (JPS)

Juvenile polyposis syndrome (JPS), also known as familial juvenile polyposis, is a rare genetic condition characterised by the development of multiple hamartomatous juvenile polyps throughout the gastrointestinal tract, as well as a predisposition for malignancy (cancer). It is caused by genetic mutations of different two tumour suppressor genes.

Familial cancer syndromes, also known as hereditary cancer syndromes, are rare conditions that cause an increased risk of cancer as the result of inherited genetic mutations in certain cancer-related genes. They can affect both adults and children, however they generally develop in people at a younger age than normal. While familial cancer syndromes are not classified as cancer, they are equally as severe and can be life-threatening as they are associated with the development of various tumours throughout the body. Having a familial cancer syndrome does not guarantee the development of cancer, however the risk of developing cancer is higher than those who do not have a familial cancer syndrome.

JPS is generally diagnosed equally among the sexes, and is often diagnosed around the age of 20. However, anyone can develop this disease.

Types of Juvenile Polyposis Syndrome

There are three primary types of JPS, which are categorised based on the localisation of the polyps and onset of symptoms.

Juvenile Polyposis of Infancy

Juvenile polyposis of infancy is a rare variant of JPS that generally diagnosed before the age of two. It is characterised by the development of polyps throughout the gastrointestinal tract, most notably in the stomach, small intestine, colon and rectum. Unfortunately, juvenile polyposis of infancy is often aggressive, and may not have as good of a prognosis as other types of JPS.

Generalised Juvenile Polyposis

Generalised juvenile polyposis is the most common type of JPS that is generally diagnosed around the age of 20. It is characterised by the development of polyps throughout the gastrointestinal tract, most notably in the stomach, small intestine, colon and rectum. Generalised juvenile polyposis can be aggressive, and regular monitoring is important to ensure the polyps don’t become cancerous.

Juvenile Polyposis Coli

Juvenile polyposis coli is a relatively common type of JPS that is generally diagnosed around the age of 20. It is characterised by the development of polyps in the colon and rectum only. Juvenile polyposis coli can be aggressive, and regular monitoring is important to ensure the polyps don’t become cancerous.

JPS is most commonly associated with the development of colorectal cancer, however it has also been linked to other types of tumours. Some examples include:

Treatment

When cancers are detected, they are staged and graded based on size, metastasis, and how the cancer cells look under the microscope. Staging and grading helps your doctors determine the best treatment for you. However, each patient with JPS will present with a unique disease behaviour, with varying tumour locations and symptoms. As such, there is no one treatment method that will work for everyone, and there is no standard staging system for this disease. Instead of staging and grading, your doctor will recommend a treatment plan based on the following factors:

  • Type of tumours present.
  • Whether the tumours are malignant (cancerous) or benign (non-cancerous).
  • Tumour location.
  • Whether or not malignant tumours have metastasised.
  • Your age.
  • General health.
  • Your treatment preferences.

Your doctor may also recommend genetic testing, which analyses your tumour DNA and can help determine which treatment has the greatest chance of success. They will then discuss the most appropriate treatment option for you.

Treatment options for tumours associated with JPS may include:

  • Surgery to remove as much of the tumour(s) as possible – these will vary based on tumour type and location.
  • Chemotherapy.
  • Radiation therapy.
  • Clinical trials.
  • Palliative care.

Cancer Screening

Once a diagnosis of JPS has been confirmed, implementing a targeted screening plan becomes essential due to the increased risk of developing certain cancers.  The content of this plan will vary from person to person based on the genetic mutation involved, your family’s history of cancer and the types of cancers that may be present. It will also outline the routine tests you should have and how regularly you should have them.  Some recommendations for JPS may include:

  • Annual physical examination with cardiovascular examination and routine blood tests.
  • Colonoscopy every 1-3 years beginning at the ages of 12-15 (earlier if symptomatic).
  • Gastroscopy every 1-3 years beginning at the age of 12-15 (earlier if symptomatic).

Screening options for JPS may evolve as new technologies are developed and our understanding of the condition grows. It is essential to discuss your individual circumstances with your healthcare team to determine the most appropriate screening plan for you.

Risk factors

JPS is caused by the following genes:

  • BMPR1A (bone morphogenetic protein receptor type 1A, tumour suppressor gene).
  • SMAD4 (SMAD family member 4, tumour suppressor gene).

JPS is an autosomal dominant disease, which means that you have a 50% chance of developing the condition if one of your parents carries the genetic mutation.

Symptoms

The symptoms of JPS often vary by the type(s) of tumours present. General symptoms of JPS may include:

  • Rectal bleeding.
  • Anaemia.
  • Bowel obstruction.
  • Intussusception.
  • Diarrhoea.
  • Rectal prolapse.
  • Failure to thrive in infants.
  • Macrocephalus.
  • Hypotonia.

Symptoms related to specific tumours can be found on our knowledgebase.

Not everyone with the symptoms above will have cancer, but see your general practitioner (GP) if you are concerned.

Diagnosis

If your doctor suspects you have tumours associated with JPS they may order some of the following tests to confirm the diagnosis and refer you to a specialist for treatment. The tests required for diagnosis will often vary based on the symptoms present, and where the tumour(s) are suspected to be located.

  • Physical examination.
  • Genetic testing.
  • Blood tests.
  • Imaging tests, potentially including:
    • MRI (magnetic resonance imaging).
    • CT (computed tomography) scan.
    • PET (positron emission tomography) scan.
  • Exploratory procedures, potentially including:
    • Flexible sigmoidoscopy.
    • Colonoscopy.
    • Proctoscopy.
    • Gastroscopy.
  • Biopsy.

References

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