Juvenile Polyposis Syndrome (JPS)

Juvenile polyposis syndrome (JPS) is a hereditary condition identified by the presence of multiple polyps (abnormal growths or tumors) in the gastrointestinal (GI) tract. In JPS, the polyps are called juvenile or inflammatory polyps. The term "juvenile" refers to the type of polyp, not the age of when the polyps occur. However, most children with JPS have some polyps by the age of 20.

Not every child with juvenile polyps has JPS. That’s why it’s critical for a GI specialist with experience in polyposis disorders to be involved in the evaluation.

The number of polyps will vary for each individual. Some people may have only four or five polyps, whereas others may have more than 100. Polyps in JPS can be found anywhere in the GI tract — from the stomach to the rectum — but they are mostly found in the large intestine.

JPS occurs in approximately one in 100,000 people and equally affects both males and females. Most juvenile polyps are non-cancerous. The risk of developing cancer is rare and generally occurs in adulthood.

Children may begin to experience symptoms during early childhood. Abnormal signs and symptoms that may develop in the course of the disease include:

• Rectal bleeding
• Diarrhea
• Anemia
• Bowel obstruction
• Visible rectal polyp

Most polyps in JPS are non-cancerous (benign). However, polyps can change and become cancerous. Colon cancer is the most serious risk of JPS, with up to a 50 percent chance of developing colon cancer during their lifetime.

JPS is usually caused by a mutation in one of two genes — SMAD4 or BMPR1A gene — and rarely a third gene, PTEN, is involved. The mutation can happen in two ways:

• It can be passed down from a parent (in 50 percent of children).
• It can be a new mutation in the SMAD4 or BMPR1A gene.

If a child has JPS and the SMAD4 gene, they may also have an associated congenital vascular condition known as hereditary hemorrhagic telangiectasia.

Not all children will have an identified mutation.

Patients are tested for juvenile polyposis syndrome by performing a colonoscopy, a procedure in which a long, flexible tube with a light and camera on the end goes inside the rectum and up into the large intestine. An upper GI endoscopy is often performed simultaneously. This procedure also uses a long, flexible tube that examines the esophagus, stomach, and small intestine.

Another way to test for JPS is by genetic testing of the SMAD4 or BMPR1A gene.

Children should be tested for JPS if they have a family history of JPS, colon cancer at a young age, or are showing any of the symptoms.

An initial test for JPS should be performed:

• By 8 to 10 years old for high-risk family history
• By 15 years old for an average-risk child
• At the time of first symptoms

Average and high-risk are determined based on family history or known high-risk gene mutations.

Most polyps are treated by removing them with an endoscope, a procedure known as a polypectomy. But when the polyps are very large or there are too many, or if they present a risk for cancer, then surgery may be necessary.

There is no cure for JPS. Treatment reduces complications, such as abdominal pain, bowel obstruction, GI bleeding, and cancer.

The Boston Children's Hospital Pediatric Polyposis Program provides comprehensive care for children with JPS. Our team specializes in the treatment of pediatric polyposis conditions, bringing together GI endoscopy, Genetics, Surgery, and other specialties when necessary. We also are fortunate to work closely with one of the top pediatric cancer centers in the country — Dana-Farber/Boston Children’s Cancer and Blood Disorders Center.