What is polyposis coli (familial adenomatous polyposis or FAP)?
FAP is an inherited condition caused by a mutation in a gene that is inherited in an autosomal dominant way. This means that each child of an affected parent has a 50 per cent (or 1 in 2) chance of inheriting FAP, while children who do not inherit FAP do not have the gene to pass onto their offspring. The condition is characterised by the formation of polyps, also known as adenomas (because they are at a pre-cancerous stage, where they may or may not develop into cancerous cells). By the time an affected individual is 15 to 20 years old, hundreds of adenomatous polyps will have developed in the colon. Although each individual polyp has a fairly low risk of becoming cancer, the patient has so many polyps that colon cancer is almost inevitable by the age of 50. Commonly, this cancer occurs much earlier in adult life unless prophylactic (preventive) colectomy (the removal of the colon) is done. Although the colon is the main site of the disease, other organs are also affected. • Individua
