APC and Familial adenomatous polyposis: Familial adenomatous polyposis (FAP; MIM#175,100) is an autosomal dominant colorectal tumour syndrome caused by a heterozygous mutation in the APC regulator of the WNT signalling pathway gene (APC; MIM*611731) on chromosome 5q22.2 and is characterised by the formation of numerous adenomatous polyps throughout the colon [1].