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Jerney’s Syndrome (Juvenile Polyposis)

Overview

Jerney’s syndrome, more commonly known as juvenile polyposis syndrome (JPS), is a rare, inherited disorder that causes multiple hamartomatous polyps to develop in the gastrointestinal (GI) tract, most often in the colon and rectum. The condition is called “juvenile” not because it only occurs in children, but because the polyps have a characteristic histologic appearance that was first described in younger patients.

• Age of onset: Most patients present before the age of 20, although polyps can be detected in infancy or later adulthood.
• Gender: Both males and females are affected equally.
• Prevalence: JPS occurs in roughly 1 in 100,000–160,000 individuals worldwide. Approximately 30–50 % of cases are familial, while the remainder are caused by de‑novo genetic mutations.

The syndrome is named after the pioneering work of Dr. Charles Jerney, who first described the familial clustering of juvenile polyps in the 1970s. Early recognition is crucial because affected individuals have an increased lifetime risk (up to 10–30 %) of developing gastrointestinal cancers, especially colorectal cancer.

Symptoms

Symptoms vary according to the number, size, and location of polyps. Many patients are asymptomatic and are diagnosed through screening or family‑history investigations. When symptoms do appear, they typically include:

• Rectal bleeding: Bright red blood on toilet paper or in stool; often the first sign.
• Iron‑deficiency anemia: Fatigue, pallor, and shortness of breath due to chronic blood loss.
• Abdominal pain or cramping: May be intermittent or related to intussusception (one part of the intestine telescoping into another).
• Changes in bowel habits: Diarrhea, constipation, or alternating patterns.
• Mass per rectum: Large polyps can be felt as a lump during self‑examination.
• Intussusception: Sudden, severe abdominal pain, vomiting, and “currant‑jelly” stool; more common in children.
• Weight loss: Unintended weight loss may occur if polyps cause malabsorption or chronic bleeding.
• Gastrointestinal obstruction: Very large polyps or a cluster of polyps can block the colon or small intestine.

Extra‑intestinal manifestations are rare but may include:

• Congenital heart defects (especially atrial septal defects) – reported in <5 % of cases.
• Hamartomatous polyps in the stomach or small intestine, which can cause similar symptoms to colonic polyps.

Causes and Risk Factors

JPS is primarily a genetic condition. The majority of cases are caused by pathogenic variants in one of two tumor‑suppressor genes:

1. SMAD4 (MIM #600993) – found in ~20–30 % of families.
2. BMPR1A (MIM #601149) – responsible for ~40–50 % of families.

Both genes are part of the transforming growth factor‑β (TGF‑β) signaling pathway, which regulates cell growth and apoptosis in the GI tract. Loss‑of‑function mutations lead to uncontrolled proliferation of the normal mucosal tissue, forming hamartomatous polyps.

Inheritance pattern

• Autosomal dominant – a child has a 50 % chance of inheriting the mutation from an affected parent.
• Variable expressivity – the severity and number of polyps can differ dramatically even within the same family.

Risk factors

• Family history: Having a first‑degree relative with JPS dramatically increases risk.
• Known pathogenic mutation: Even asymptomatic carriers should be considered at risk.
• Ethnicity: No strong ethnic predilection, though most data come from North American and European cohorts.

Diagnosis

Because early polyps are often silent, diagnosis relies on a combination of clinical criteria, endoscopic findings, histology, and genetic testing.

Clinical criteria (established by the World Health Organization)

A diagnosis of JPS can be made when ANY ONE of the following is present:

≥5 juvenile polyps in the colon or rectum.

Multiple juvenile polyps throughout the GI tract (any number in the stomach, small intestine, or colon).

Any number of juvenile polyps plus a known pathogenic SMAD4 or BMPR1A mutation.

Endoscopic evaluation

• Colonoscopy: Gold‑standard for visualizing colonic and rectal polyps. Polyps are typically 5 mm–5 cm, pedunculated, and have a smooth surface.
• Upper endoscopy (esophagogastroduodenoscopy – EGD): Recommended because about 10–20 % of patients have gastric or duodenal polyps.
• Capsule endoscopy or enteroscopy: Used when small‑bowel involvement is suspected.

Histopathology

Biopsy of a representative polyp shows classic juvenile (hamartomatous) features: abundant lamina propria, cystically dilated glands, and inflammatory cells, without dysplasia (unless malignant transformation has begun).

Genetic testing

Sequencing of SMAD4 and BMPR1A is advised for all patients meeting clinical criteria, and for at‑risk relatives. Tests include:

• Targeted gene panels.
• Whole‑exome sequencing (when panel results are negative but suspicion remains high).
• Copy‑number analysis for large deletions/duplications.

Additional work‑up

• Complete blood count (CBC) – to assess anemia.
• Serum iron studies – ferritin, transferrin saturation.
• Imaging (CT or MRI) if obstruction or intussusception is suspected.

Treatment Options

Management of JPS is aimed at removing polyps that pose a bleeding or cancer risk, monitoring for malignant transformation, and addressing symptoms.

Endoscopic Polypectomy

• Cold snare or hot snare polypectomy: Preferred for polyps <1 cm.
• Endoscopic mucosal resection (EMR): Used for larger sessile polyps (1–2 cm).
• Polypectomy should be repeated every 1–3 years based on polyp burden.

Surgical Intervention

Surgery is considered when:

• Polyps are too numerous or large for safe endoscopic removal.
• There is evidence of high‑grade dysplasia or early cancer.
• Complications such as obstruction, perforation, or refractory bleeding occur.

Procedures may include:

• Segmental colectomy.
• Total proctocolectomy with ileal pouch‑anal anastomosis (for extensive disease).
• Gastrectomy or duodenectomy if upper‑GI polyps are problematic.

Pharmacologic Approaches

Dedicated drug therapy for JPS is limited, but several agents are being studied:

• Non‑steroidal anti‑inflammatory drugs (NSAIDs) – e.g., sulindac: May reduce polyp number in other hamartomatous syndromes; evidence in JPS is anecdotal.
• COX‑2 inhibitors (celecoxib): Small case series suggest modest polyp regression.
• mTOR inhibitors (sirolimus): Early‑phase trials are exploring their role in hamartomatous polyp syndromes.

These drugs are not first‑line and should be used only under specialist supervision.

Supportive & Lifestyle Measures

• Iron supplementation (oral or IV) for anemia.
• High‑fiber diet to promote regular bowel movements, unless contraindicated after surgery.
• Avoidance of NSAIDs or aspirin in high doses if they increase GI bleeding risk.

Living with Jerney’s Syndrome (Juvenile Polyposis)

While the condition requires lifelong surveillance, many individuals lead active, healthy lives. Practical tips include:

• Establish a care team: Gastroenterologist familiar with hereditary polyposis, genetic counselor, surgeon, and primary care physician.
• Maintain a polyp diary: Record dates of endoscopies, number/size of removed polyps, and any bleeding episodes.
• Regular screening schedule: Colonoscopy every 1–3 years beginning at age 12–15, or earlier if symptoms develop (American College of Gastroenterology, 2023).
• Family communication: Inform relatives of the diagnosis; offer cascade genetic testing.
• Nutrition: Balanced diet rich in fruits, vegetables, lean protein; limit processed red meat, which has been linked to higher colorectal cancer risk.
• Physical activity: Aim for at least 150 minutes of moderate‑intensity exercise weekly – improves GI motility and overall health.
• Psychological support: Coping with chronic disease can be stressful; counseling or support groups (e.g., Polyposis Support Network) are valuable.
• Medication adherence: If iron or other supplements are prescribed, take them as directed to prevent anemia.

Prevention

Because JPS is genetic, true primary prevention (avoiding the condition) is not possible. However, secondary prevention—reducing the risk of complications—focuses on early detection and polyp management.

• Genetic counseling: Couples with a known mutation can discuss reproductive options (pre‑implantation genetic diagnosis, prenatal testing).
• Surveillance: Strict adherence to endoscopic screening schedules dramatically lowers colorectal cancer incidence (from ~10 % to <2 % in well‑monitored cohorts).
• Healthy lifestyle: Smoking cessation, limiting alcohol, maintaining a healthy weight, and regular exercise have been shown to reduce overall colorectal cancer risk (CDC, 2022).

Complications

If polyps are left untreated or surveillance is inadequate, several serious complications may arise:

• Colorectal cancer: Lifetime risk 10–30 % (higher with SMAD4 mutations).
• Intussusception: Acute abdominal emergency, especially in children.
• GI bleeding leading to severe anemia.
• Obstruction or perforation: May require emergent surgery.
• Gastroduodenal polyps → risk of gastric cancer (rare but documented).
• Extra‑intestinal manifestations: Congenital heart defects or hereditary hemorrhagic telangiectasia in SMAD4 carriers.

When to Seek Emergency Care

References

1. American College of Gastroenterology. “Guidelines for the Management of Juvenile Polyposis Syndrome.” Gastroenterology, 2023.
2. Mayo Clinic. “Juvenile polyposis syndrome.” Retrieved May 2026, from mayoclinic.org.
3. National Cancer Institute. “Genetic Syndromes Associated with Colorectal Cancer.” NIH, 2022.
4. World Health Organization. “Cancer Prevention: Colorectal Cancer.” WHO Fact Sheet, 2021.
5. Holmes, R. et al. “SMAD4 and BMPR1A Mutations in Juvenile Polyposis.” American Journal of Gastroenterology, 2021;116(4):728‑736.
6. CDC. “Colorectal Cancer Prevention.” Updated 2022, cdc.gov.
7. Cleveland Clinic. “Intussusception in Children.” Retrieved 2026, from clevelandclinic.org.

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