Health condition
Juvenile polyposis syndrome
Juvenile polyposis syndrome causes multiple hamartomatous 'juvenile' polyps in the colon and stomach - the name describes the polyp type, not the patient's age - with an increased bowel and gastric cancer risk, and an important overlap with hereditary haemorrhagic telangiectasia.
Why trust this guide
- 01
Editorial team
Written by our editorial team from the UK sources listed on each page.
- 02
Sourced from guidance
Checked against current NHS and UK specialist society guidance at the time of review.
- 03
Current for 2026
Reviewed on 2026-09-27 with the next review scheduled for 2027-09-27.
Key facts
The essentials at a glance.
Which gene and test confirm it, who should be tested in the family, and which specialist to see.
-
Caused by SMAD4 or BMPR1A variants; autosomal dominant
-
Defined by multiple juvenile polyps (five or more in the colon, or any number with a family history); presentations include bleeding, anaemia or prolapsing polyps
-
Surveillance: colonoscopy and gastroscopy every 1-3 years from the mid-teens; SMAD4 carriers need gastric attention especially
-
SMAD4 variants can also cause hereditary haemorrhagic telangiectasia - screening for nosebleeds, anaemia and lung arteriovenous malformations matters
Understanding the condition
What it is and what happens next.
What causes it, how it is confirmed, and the testing and specialist routes available in the UK.
What it is and how it presents
A single juvenile polyp in a child is common and innocent; a syndrome declares itself through numbers, recurrence and family pattern. In adults, JPS typically means a colon that keeps producing fleshy, bleeding polyps and - in SMAD4 families particularly - a stomach that can become carpeted enough to threaten anaemia and malignancy. The SMAD4 double act with HHT is the syndrome's most practical secret: the same variant can put arteriovenous malformations in the lungs, which are screenable and treatable.
Testing, surveillance and specialist care
Confirmed families receive scheduled two-way endoscopic surveillance with polypectomy as the workhorse and surgery reserved for uncontrollable polyp burden, while SMAD4 carriers add HHT screening including chest imaging. Genetic testing sorts affected relatives from unaffected ones early enough for surveillance to start on time, with counselling for the generation below. NHS clinical genetics services carry some of the longest waits in the health service, often many months for a first appointment, whereas private genetic testing and a specialist review can typically be arranged within around two weeks.
Seeing a specialist
Who to see, and how quickly you can be seen.
The specialist for this condition is usually a gastroenterologist at a specialist polyposis service. Your GP can refer you on the NHS, or you can arrange a private consultation directly.
A quiet reminder
This guide is for information, not medical advice.
Your GP knows your history and can tell you which parts apply to you. If in doubt, see them - and seek urgent care for any emergency symptoms.
Frequently asked
Common questions about Juvenile polyposis syndrome.
Quick, plain-English answers to what people ask us most.
-
What is juvenile polyposis syndrome?
Juvenile polyposis syndrome is an inherited condition causing multiple polyps to grow in the digestive tract, most often in the colon and rectum, starting from childhood. Despite the name, it can be diagnosed at any age, and the polyps carry an increased risk of becoming cancerous over time.
-
What causes juvenile polyposis syndrome?
It is usually caused by mutations in the SMAD4 or BMPR1A genes, inherited in an autosomal dominant pattern, meaning an affected parent has a 50% chance of passing it to each child. Some cases arise from a new mutation with no family history.
-
What are the symptoms of juvenile polyposis syndrome?
Common symptoms include rectal bleeding, abdominal pain, anaemia from chronic blood loss, and polyps that may prolapse or cause bowel obstruction. Some patients also have associated blood vessel abnormalities if the SMAD4 mutation coexists with hereditary haemorrhagic telangiectasia.
-
Is juvenile polyposis syndrome dangerous?
Yes, it carries a significantly increased lifetime risk of colorectal and, in some cases, gastric cancer, so regular surveillance colonoscopy is essential. With consistent monitoring and timely polyp removal, cancer risk can be substantially reduced.
-
Is juvenile polyposis syndrome genetic?
Yes, it is a genetic condition, and genetic testing is recommended for affected individuals and their first-degree relatives to guide surveillance. Family members who test positive need their own regular screening even before symptoms develop.
-
Can juvenile polyposis syndrome be cured?
There is no cure for the underlying genetic condition, but regular endoscopic surveillance and polyp removal effectively manage the disease and reduce cancer risk. In severe cases, surgical removal of part of the colon may be needed.
-
How is juvenile polyposis syndrome treated?
Treatment centres on regular colonoscopy and, where relevant, upper endoscopy to detect and remove polyps before they become cancerous. Surgery is reserved for extensive polyp burden, bleeding that can't be controlled endoscopically, or confirmed cancer.
-
How often do I need surveillance for juvenile polyposis syndrome?
Surveillance intervals depend on polyp burden and are individualised, but colonoscopy every one to three years is typical once polyps are found, sometimes more frequently. Your gastroenterologist will tailor the schedule to your specific findings and genetics.
-
Juvenile polyposis vs familial adenomatous polyposis — what's the difference?
Both are inherited polyposis syndromes with cancer risk, but they involve different genes and different polyp types: juvenile polyposis causes hamartomatous polyps via SMAD4/BMPR1A mutations, while familial adenomatous polyposis causes numerous adenomatous polyps via APC gene mutations and generally carries an even higher, near-certain cancer risk without treatment.
-
When should I see a doctor about juvenile polyposis syndrome, and how quickly can I be seen privately?
Unexplained rectal bleeding, especially in a child or someone with a family history of polyps, should prompt gastroenterology referral without delay. Private gastroenterology assessment can typically be arranged within about two weeks, compared with much longer NHS routine referral waits.