What Is Juvenile Polyposis Syndrome?

Overview

Juvenile polyposis syndrome (JPS) is a genetic disorder characterized by benign tumours (polyps) in the gastrointestinal tract. The colon is where these polyps are most frequently discovered, followed by the rectum, stomach, and small intestine. JPS patients are more likely to develop colorectal, gastric, upper gastrointestinal, and pancreatic malignancies, among other cancers. JPS is passed down through families in an autosomal dominant manner. The word "juvenile" in the condition's name refers to the features of the polyp tissues under the microscope, not the age of the affected individual. JPS symptoms can include diarrhoea, stomach pain, anaemia, and gastrointestinal bleeding. It's important to note that individuals with JPS typically develop polyps before the age of 20. Throughout a person's life, the number of polyps can range widely, from just a few to more than a hundred.

Types of juvenile polyposis syndrome

Juvenile polyposis syndrome is classified into three main types based on the characteristics and associated symptoms. 

1. Juvenile polyposis of infancy (JPI) is the most severe form and affects infants and young children. Polyps can grow across the entire gastrointestinal system in JPI, and they are associated with unfavourable outcomes. Children with JPI may also experience a  protein-losing enteropathy, a condition that causes severe diarrhoea, failure to thrive (gain weight and growth), and overall weight loss.^1,2
2. Generalized juvenile polyposis is the most common type of JPS, in which polyps may grow anywhere in the gut, including the stomach, colon, and small intestine.
3. Juvenile polyposis coli, particularly, involves the development of polyps in the colon. Polyps frequently appear in this type of JPS patients during childhood.

Although JPS can afflict people of any age, symptoms for those with generalized juvenile polyposis and juvenile polyposis coli typically start during childhood.

Causes of juvenile polyposis syndrome

Juvenile polyposis syndrome is caused by specific changes in the BMPR1A and SMAD4 genes. These genes are essential for controlling cell development and signalling inside cells. The normal signalling and regulation processes are interfered with by mutations in these genes, which results in uncontrolled cell growth and the development of polyps in the digestive tract.³ Although these gene changes account for 40 - 60% of JPS cases, the exact cause of JPS is still unknown in some instances.^4,5

JPS follows an autosomal dominant inheritance pattern, which means that a person only needs to inherit one copy of the mutated gene to develop the condition. Each cell in people with JPS has two copies of the BMPR1A or SMAD4 gene, one of which is healthy and the other is mutated. Accordingly, there is a 50% chance that a parent who carries the mutant gene will also pass it on to their child. Approximately 75% of patients with JPS have a family history, while 25% have spontaneous genetic alterations.⁶ Even if the mutation is new in the family, each child of these individuals still has a 50% chance of inheriting it. Compared to BMPR1A mutations, SMAD4 mutations in JPS are associated with more extensive upper gastrointestinal polyps and an increased risk of stomach cancer.  Early-onset juvenile polyposis of infancy can occur in patients with recurrent mutations in the BMPR1A gene and occasionally in the neighbouring PTEN gene.⁷

Signs and symptoms of juvenile polyposis syndrome

The presence of polyps in the GI tract is a defining feature of JPS. The colon, rectum, small intestine, and stomach are where these polyps are most frequently discovered. They appear as red-purple circular protrusions inside the intestine. While polyps are typically not visible from the outside, they occasionally can be seen protruding from the rectum. Most patients are symptomatic by the age of 20.⁸ 90% of individuals with gastrointestinal polyps present with GI bleeding and subsequent anaemia.⁴ The most common initial sign is bleeding in the rectum.

Other symptoms like persistent weight loss, constipation, cramping or stomach pain, diarrhoea, and anaemia-related fatigue and weakness may also occur.

About 15% of people with JPS may be born with extra symptoms, such as a cleft palate, extra fingers or toes, brain or heart abnormalities, twisted intestines, or skin telangiectasia (dilated blood vessels).

Juvenile polyposis of infancy is characterised by the presence of multiple polyps scattered throughout the upper and lower GI tract. This type of JPS can cause infants to develop poorly despite receiving adequate nutrition due to extensive diarrhoea, severe weight loss (cachexia), and protein-losing enteropathy. They also develop rectal bleeding, anaemia, intussusception, and bowel obstruction as a result of the intestines twisting around big or strategically located polyps in addition to these symptoms. Macrocephaly and hypotonia may also occur, and patients often die at an early age.

Management and treatment for juvenile polyposis syndrome

JPS management involves the following:

• Removal of polyps is the main goal of JPS treatment in order to reduce symptoms. Treatment options can vary depending on age, health, and the characteristics of the polyp:
  •  Polyp removal during endoscopic examinations.
  •  Removal of polyps via surgery.
  •  In cases with multiple polyps, surgical removal of a section of the stomach or intestines.
• For those with JPS or those who are at risk, regular GI tract surveillance is crucial. This includes screening for the stomach, small bowel, and colon cancers.
  • A colonoscopy should be done every one to three years, beginning between the ages of 12 and 15, or sooner if symptoms are present, in order to detect colorectal cancer. If polyps are discovered, a yearly colonoscopy may be required; otherwise, the intervals might be extended.⁹
  • Starting at the age of 12, an upper endoscopy is advised to check for polyps as a risk for upper GI tract cancer. If polyps are found, an annual upper endoscopy may be required; otherwise, it can be done every two to three years.¹⁰
  • Evaluation of the small intestine using imaging or endoscopic methods, with a frequency based on the presence or symptoms of polyps.
  • Advanced dysplasia, numerous gastric polyps, or gastric cancer may all necessitate partial or total removal of the stomach (gastrectomy).

Diagnosis

A physical examination, a discussion of the patient's symptoms, and a study of the patient's family and medical history are all steps in the healthcare provider's diagnosis of JPS. Doctors will consider a diagnosis of JPS if a person meets any of the following criteria:

1. Five or more juvenile polyps in the colorectum
2. Two or more juvenile polyps in other parts of the GI tract
3. Any number of juvenile polyps in individuals with a first-degree relative who has a known history of having juvenile polyps

Your doctor might recommend a number of tests to confirm the diagnosis if JPS is suspected, including 

• an endoscopic exam, such as a colonoscopy.  For the purpose of identifying and locating polyps in the lower GI tract, this technique involves passing a flexible, thin endoscopic tube into the rectum. If polyps are discovered, a biopsy is also performed. 
• A genetic blood test that examines a sample of your blood or saliva to look for particular gene mutations linked to JPS, like those in the BMPR1A or SMAD4 genes.¹⁰ Both of these two genes are mutated in about 40% of patients with JPS. It's crucial to keep in mind that there may be additional JPS-related genes that are still undiscovered. Consequently, JPS is not always ruled out if a negative genetic test result is obtained.

FAQs

How can I prevent juvenile polyposis syndrome?

Juvenile polyposis syndrome (JPS) cannot be prevented because it is a genetic disorder, however, early polyp detection is made feasible by improved awareness, education, and screenings. Through prompt treatment, early detection lowers the likelihood of symptoms and cancer.

How common is juvenile polyposis syndrome

JPS is a rare condition, with an estimated incidence rate of 1 in 100,000.

Who is at risk of juvenile polyposis syndrome?

A family history of juvenile polyposis gene mutations like BMPR1A or SMAD4 are the main risk factor for the disorder. Despite the fact that possessing these risk factors makes JPS more likely to occur, it's crucial to remember that not everyone who possesses them will experience the condition.

What can I expect if I have juvenile polyposis syndrome?

The majority of juvenile polyps are benign (non-cancerous), but there is a chance that they could develop into cancerous (malignant) growths. An estimated 10- 50% of people with juvenile polyposis syndrome (JPS) are at risk of acquiring gastrointestinal cancer. The most frequently observed cancer is colorectal cancer, although pancreatic, small intestine and stomach cancers can also occur. It is crucial to follow your healthcare provider's advice for routine screenings, which may be suggested annually or every few years, in order to reduce the risk.

When should I see a doctor?

If you have a family history of juvenile polyposis syndrome, experience symptoms like gastrointestinal bleeding or abdominal pain, notice polyps in your gastrointestinal tract, or have questions about screenings and prevention, it is recommended to see a doctor for evaluation and guidance.

Summary

Juvenile polyposis syndrome is an autosomal dominant condition characterised by benign polyps in the gastrointestinal tract. It raises the risk of colorectal, gastric, upper gastrointestinal, and pancreatic cancer. JPS can cause symptoms like diarrhoea, stomach pain, anaemia, and gastrointestinal bleeding. The diagnosis process includes a physical examination, an analysis of the family history, and specialised procedures such as colonoscopies and genetic tests. Removal of polyps is a key component of management, as is routine surveillance with tests like colonoscopies, upper endoscopies, and small bowel examinations. The risk of symptoms and cancer must be reduced through early detection and treatment. It is advised to get a medical checkup if there is a family history, symptoms, or concerns.