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last update : 13/07/2006
Symbol JPS
Location 18q21.2
Name juvenile polyposis syndrome
Corresponding gene SMAD4
Other symbol(s) FJP
Main clinical features
  • colon cancer predisposition syndrome
  • congenital anomalies, hamartomatous polyps in the gastrointestinal tract, and the development of tumors in these tissues
  • phenotypic overlap with other hamartomatous polyposis syndromes.
  • Genetic determination autosomal dominant
    Prevalence 1 in 100,000 births
    Related entries JPS2, JPS3, JPS4 and forms associated with hereditary hemorrhagic telangiectasia and arteriovenous malformation (JPHT)
    Function/system disorder digestive tract/gastrointestinal
    Type malignancy
    Gene product
    Name MAD homolog 4 (MADH4)
    Gene mutationChromosome rearrangementEffectComments
    deletion     deletion (1244-1247 del AGAC), mutations likely accounting for a minority of cases
    various types      
    deletion     large genomic deletions detected using MLPA
    Remark(s) germline point mutations and large genomic deletions detected in SMAD4, BMPR1A (see JPS3) and more rarely in PTEN (see JPS2).
    Genotype/Phenotype correlations strong correlation for gastric polyposis, gastric cancer, and hereditary hemorrhagic telangiectasia ; wide distribution of different polyp types comparable with that described in hereditary mixed polyposis syndromes (see HMPS2).