Juvenile polyposis of childhood D12.6

Autosomal dominant inherited disease characterized by juvenile hamarous polyps in the gastrointestinal (GI) tract.

A distinction is made between 3 forms, which differ in the location of the polyps:

• generalized juvenile polyposis of the upper and lower digestive tract
• juvenile polyposis coli juvenile gastric polyposis
• more severe infantile form

Prevalence: Unknown; estimated annual incidence is between 1:100,000 and 1:15,000.

Mutations in the genes SMAD4 (18q21.1) and BMPR1A (10q22.3) are detected in 40% of patients. Gastric polyposis is more frequently found in SMAD4 carriers than in BMPR1A carriers. In about 25% of SMAD4 mutation carriers, JPS is associated with Hereditary Haemorrhagic Teleangiectasia (Juvenile Polyposis/Hereditary Haemorrhagic Teleangiectasia Syndrome).

Infancy, childhood, youth, adulthood

In all subtypes of JIP the clinical signs are isolated bleeding in the rectum, anemia, abdominal pain, intussusception and diarrhea. Rectal prolapse and spontaneous anal excretion of polyps has been observed in juvenile polyposis coli and in generalized juvenile polyposis.

Composite diagnosis consisting of clinical picture, family history, endoscopic findings and histological analysis of the polyps, molecular analysis.

> 5 juvenile polyps in the colon and/or rectum; juvenile polyps in the entire digestive tract including the stomach; any number of polyps in cases of JIP in the family.

Other syndromes with polyposis: Cowden's syndrome; Bannayan-Riley-Ruvalcaba syndrome, Familial adenomatous polyposis and Peutz-Jeghers syndrome.

Possible accompanying symptoms are growth retardation and edema.

If the number of polyps remains low, endoscopic polypectomy is the therapeutic gold standard. Because of the risk of carcinoma and a further extension of the polyposis, surgical intervention of a colectomy with proctectomy and ileo-anal anastomosis can also be recommended.

The prognosis of JIP is determined by the risk of developing gastrointestinal or pancreatic carcinoma after the age of 20. The cumulative risk of developing a malignoma in patients with JIP is 20% at age 35 and 68% at age 60. The cancer risk is even higher in patients with generalized juvenile polyposis.