It is caused by a mutation in the tumour supressor gene APC on chromosome 5.
The appearance of the colon is:
Treatment tends to be a colectomy before cancer develops.
As an aside, a variation of FAP called 'Gardners Syndrome' exists. This is FAP plus osteomas, epidermal cysts, fibromas and retinal pigmentation.
So after 2 conditions which are defined by polyps, lets look at one which defines itself by not having polyps - Hereditary Non-Polyposis Colorectal Cancer
