Juvenile Polyposis Syndrome

Epidemiology and Etiology:

· Autosomal dominant injeritance

· SMAD4/DPC4

· mutations (20%)

· deletions (6%)

· TGF-beta signaling intermediate

· Combined JPS/HHT (Hereditary Hemorrhagic Telangiectasia) in 15-22% of those with SMAD4 mutation

· BMPR1A

· Mutations (20%)

· Deletions (7%)

Common sites:

· GI tract

· Juvenile polyps (50-100 average)

· Adenoma

· Adenocarcinoma (9-50% risk)

· Colon (most)

· pancreas

Gross features:

·

Histologic features:

·

Immunophenotype:

Marker:

Sensitivity:

Specificity:

Molecular features:

· Sequencing of SMAD4 and BMP1A

· MLPA for deletions

Other features:

· Bleeding

· Anemia

· Clinical diagnosis (any one of):

· > 5 juvenile polyps in the colorectum

· Multiple juvenile polyps throughout the GI tract

· Family history plus any number of juvenile polyps

References:

· Kumar V, Fausto N, Abbas A. Robbins & Cotran Pathologic Basis of Disease, Seventh Edition. 7th ed. Saunders; 2004.

· Genetests.org