Last updated:
07/28/2025
Years published: 2025
NORD gratefully acknowledges Sean Dailey, MS, CGC, Gioconda Alyea, MD (FMG), MS, National Organization for Rare Disorders and Suzanne P. MacFarland, MD, Department of Pediatrics, Division of Oncology, Children’s Hospital of Philadelphia, University of Pennsylvania, for the preparation of this report.
Summary
Juvenile polyposis syndrome (JPS) is a rare genetic condition associated with an increased chance of developing non-cancerous growths in the gastrointestinal (GI) tract called hamartomatous polyps. These polyps can appear in the stomach, small intestine, colon and rectum.1-2 “Juvenile” refers to the type of polyp, not the age when someone starts to develop them.1
Symptoms may be different for each person. Most people with JPS have polyps by the time they are 20 years old. Some may get only a few polyps throughout their lives while others may get more than 100. The age of onset and number of polyps may vary even among members of the same family. Most polyps are non-cancerous, but they may become cancerous over time and people with JPS have a higher risk of developing GI cancer, especially colon cancer. Other cancers, like stomach, upper GI and pancreatic cancer have also been reported.1-2 Polyps may cause bleeding and low levels of red blood cells (anemia) if left untreated.1
There are three subtypes of JPS defined by where the polyps are located and the onset of the associated symptoms: juvenile polyposis of infancy, generalized juvenile polyposis and juvenile polyposis coli.
About 60% of people with JPS have a change (variant) in the BMPR1A or SMAD4 gene. The others have a specific change that has not been found or a change in a gene that has not been identified yet.1
Juvenile polyposis of infancy occurs due to a large deletion (loss) within chromosome 10 that includes both the BMPR1A and PTEN genes.
Individuals with a BMPR1A disease-causing variant typically develop polyps. People with a SMAD4 variant may develop polyps and a condition called hereditary hemorrhagic telangiectasia (HHT). HHT is a genetic condition that causes abnormal development of blood vessels which can lead to frequent or serious bleeding.1,3,4
JPS is an autosomal dominant condition, which means that it may be passed down in families and a disease-causing change (variant) in just one copy of a gene is enough to cause the condition.1-2
A diagnosis of JPS is often suspected based on signs and symptoms and confirmed with a genetic test. There is currently no cure, but having a diagnosis allows for appropriate monitoring and treatment of associated symptoms.1 Some people with JPS do not have a gene variant causing JPS, but the diagnosis can also be made based on features like the number and location of polyps.
JPS is associated with an increased chance of developing non-cancerous growths (hamartomatous polyps) in the gastrointestinal tract, specifically in the stomach, small intestine, colon and rectum. These polyps may vary in size, shape and number. Some people with JPS may only have a few polyps while others may have more than 100. Polyps may develop from infancy through adulthood, but the peak age is around 20 years old.1,2
Clinically JPS can be divided into three subtypes according to the localization of the polyps and the onset of the associated symptoms;5
Additionally, people with variants in the SMAD4 gene often have symptoms of both JPS and hereditary hemorrhagic telangiectasia (HHT) which is known as “juvenile polyposis/hereditary hemorrhagic telangiectasia syndrome”.6
HHT is an inherited condition that causes blood vessels to form abnormally which can lead to unusual or excessive bleeding. Common features include frequent nosebleeds (epistaxis) and abnormal development of blood vessels in the lungs, liver and brain.1,3,4
Most polyps are not cancerous; however, they may become cancerous if left untreated. People with JPS have an increased chance of developing cancer, specifically in the colon and rectum, but cancers of the stomach, upper GI tract and pancreas have also been reported. If left untreated, polyps may also cause bleeding and low levels of red blood cells (anemia).1,2
JPS is caused by changes (variants) in either the BMPR1A or SMAD4 gene. These genes give the body instructions to make proteins that help control important processes in cells. These proteins can attach to DNA to help turn certain genes on or off. The exact way that variants in these genes cause polyps to form is currently unknown.1
The subtype known as juvenile polyposis of infancy is caused by a large deletion in chromosome 10 that includes both the BMPR1A and PTEN genes. HHT has been reported in 15% to 81% of individuals with a SMAD4 variant, depending on the study.7
Some people have the features of JPS but lack identifiable disease-causing variants in the BMPR1A or SMAD4 genes. This is called variant-negative JPS. It is not known yet why people with variant-negative JPS develop polyps, but it is thought that in these people, JPS is caused by variants in other genes not yet identified.
Inheritance
JPS is inherited in an autosomal dominant pattern. Dominant genetic conditions occur when only a single copy of a disease-causing gene variant is necessary to cause the disease. The gene variant can be inherited from either parent, or it can be the result of a new (de novo) change in the affected individual that is not inherited. The risk of passing the gene variant from an affected parent to a child is 50% for each pregnancy. The risk is the same for males and females. Approximately 75% of cases caused by a variant in the BMPR1A or SMAD4 genes are inherited from a parent and 25% arise from a new (de novo) variant that appears for the first time in the affected person and is not inherited.1 In people with variant-negative JPS, less than 10% have a family history of JPS.1
The incidence of JPS is between 1 in 100,000 and 1 in 160,000 individuals. Males and females are affected equally, and it is not more commonly found in people of a particular racial or ethnic group.1
JPS may be suspected when someone has the following clinical features:1
Some key recommendations from a new consensus statement released by the U.S. Multi-Society Task Force on Colorectal Cancer for juvenile polyposis syndrome include:7
The diagnosis of JPS syndrome is confirmed with any one of the following features:1
There is currently no cure for JPS. Treatment involves managing symptoms through a multidisciplinary approach to improve quality of life and reduce complications and cancer risks.1
A consultation with a gastroenterologist is recommended at diagnosis for all individuals with JPS to assess for abdominal pain, rectal bleeding and changes in bowel movements. A colonoscopy and upper endoscopy are recommended every 1–3 years, starting at ages 12–15, or earlier if symptoms occur.1,7
An evaluation by a hematology/cardiology specialist is recommended at diagnosis for individuals with a SMAD4 disease-causing variant to assess for complications related to HHT.1
Genetic counseling is recommended for individuals affected by JPS and their families. The genetic counselor can provide information about how JPS is passed down in families, coordinate genetic testing and offer additional resources and support.1
Information on current clinical trials is posted on the Internet at https://clinicaltrials.gov/. All studies receiving U.S. Government funding, and some supported by private industry, are posted on this government web site.
For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:
Tollfree: (800) 411-1222
TTY: (866) 411-1010
Email: [email protected]
Some current clinical trials also are posted on the following page on the NORD website:
https://rarediseases.org/living-with-a-rare-disease/find-clinical-trials/
For information about clinical trials sponsored by private sources, contact:
https://www.centerwatch.com/
For information about clinical trials conducted in Europe, contact:
https://www.clinicaltrialsregister.eu/
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The Genetic and Rare Diseases Information Center (GARD) has information and resources for patients, caregivers, and families that may be helpful before and after diagnosis of this condition. GARD is a program of the National Center for Advancing Translational Sciences (NCATS), part of the National Institutes of Health (NIH).
View reportOrphanet has a summary about this condition that may include information on the diagnosis, care, and treatment as well as other resources. Some of the information and resources are available in languages other than English. The summary may include medical terms, so we encourage you to share and discuss this information with your doctor. Orphanet is the French National Institute for Health and Medical Research and the Health Programme of the European Union.
View reportOnline Mendelian Inheritance In Man (OMIM) has a summary of published research about this condition and includes references from the medical literature. The summary contains medical and scientific terms, so we encourage you to share and discuss this information with your doctor. OMIM is authored and edited at the McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine.
View reportGeneReviews has an article on this condition covering diagnosis, management, and inheritance. Each article is written by one or more experts on the specific disease and is reviewed by other specialists. The article contains medical and scientific terms, so we encourage you to share and discuss this information with your doctor. The GeneReviews database is managed by the University of Washington.
View reportMedlinePlus has information about this condition that may include a description, frequency, causes, inheritance, and links to more information. The information is written for the public, including patients, caregivers and families. MedlinePlus is a service of the National Library of Medicine (NLM), which is part of the National Institutes of Health (NIH).
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