Familial adenomatous polyposis

Familial adenomatous polyposis, abbreviated FAP and also known as familial polyposis coli and adenomatous polyposis coli‎, is a genetic condition that predisposes to adenomatous polyps and thus invariably results in colorectal cancer.

Gardner syndrome is a subset of FAP. Both FAP and Gardner syndrome have a mutation in the FAP gene.

Inheritance

• Autosomal dominant.

Gene

• APC gene mutation.

Variants

It comes in two main flavours:

1. FAP (no otherwise specified - the plain vanilla flavour).
   • Many polyps - typically > 100.
2. Attenuated FAP, abbreviated AFAP.
   • Less polyps - typically 10 to 100.
     • As one my think... they tend to get cancer later than (the plain vanilla) FAP.

Associations

Benign things:

• Fundic gland polyps.

Tumours:

• Hepatoblastoma.
• Colorectal carcinoma.
• Gastric adenocarcinoma.
• Papillary thyroid carcinoma, cribriform-morular variant.

Benign tumours:

• Osteomas.
• Desmoid tumour.

Prevalence

1/11,300-37,600 in Europe.

See also

• Colorectal carcinoma.
• Adenomatous polyps.
• MUTYH polyposis syndrome - an autosomal recessive polyposis syndrome.