Endoscopic image of sigmoid colon of patient with familial adenomatous polyposis
Specialty
Gastroenterology, Oncology
Complications
Colorectal cancer
Usual onset
<35 years of age
Duration
Lifelong
Types
Classical or attenuated
Causes
APC gene mutation
Diagnostic method
Colonoscopy Genetic testing
Differential diagnosis
Lynch syndrome, MUTYH-associated polyposis
Treatment
Colonoscopy Polypectomy Upper endoscopy Colectomy
Frequency
1 in 10,000 - 15,000
Familial adenomatous polyposis (FAP) is an autosomal dominant inherited condition in which numerous adenomatous polyps form mainly in the epithelium of the large intestine. While these polyps start out benign, malignant transformation into colon cancer occurs when they are left untreated. Three variants are known to exist, FAP and attenuated FAP (originally called hereditary flat adenoma syndrome[1]) are caused by APC gene defects on chromosome 5 while autosomal recessive FAP (or MUTYH-associated polyposis) is caused by defects in the MUTYH gene on chromosome 1. Of the three, FAP itself is the most severe and most common; although for all three, the resulting colonic polyps and cancers are initially confined to the colon wall. Detection and removal before metastasis outside the colon can greatly reduce and in many cases eliminate the spread of cancer.
The root cause of FAP is understood to be a genetic mutation—a change in the body's tumour suppressor genes that prevent development of tumours. The change allows numerous cells of the intestinal wall to develop into potentially cancerous polyps when they would usually reach the end of their life; inevitably one or more will eventually progress and give rise to cancer (7% risk by age 21, rising to 87% by age 45 and 93% by age 50). These gene changes do not trigger cancer, but rather, they reduce the body's ability to prevent cells from becoming cancerous. Even with the gene change, it may still take time before a cell actually does develop that is cancerous as a result, and the gene may in some cases still partially operate to control tumours, therefore cancer from FAP takes many years to develop and is almost always an adult-onset disease.
The second form of FAP, known as attenuated familial adenomatous polyposis has the APC gene functional but slightly impaired. It is therefore somewhat able to operate as usual. Attenuated FAP still presents a high 70% lifetime risk of cancer (as estimated), but typically presents with far fewer polyps (typically 30) rather than the hundreds or thousands usually found in FAP,[2] and arises at an age when FAP is usually no longer considered likely—typically between 40 and 70 years old (average 55[3]) rather than the more usual 30s upward. Because it has far fewer polyps, options for management may be different.[2]
The third variant, autosomal recessive familial adenomatous polyposis or MUTYH-associated polyposis, is also milder and, as its name suggests, requires both parents to be 'carriers' to manifest the condition.
In some cases FAP can manifest higher in the colon than usual (for example, the ascending colon,[citation needed] or proximal to the splenic flexure, or in the stomach or duodenum[1]) where they show no symptoms until cancer is present and greatly advanced. APC mutations have been linked to certain other cancers such as thyroid cancer. As the mutation causing FAP is autosomal dominant, it can be inherited directly from either parent to a child. A genetic blood test of the APC gene exists that can determine whether it is present, and therefore can predict the possibility of FAP. Individuals at risk (due to family links or genetic testing) are usually offered routine monitoring of the intestinal tract every 1–3 years for life, from puberty for FAP and early adulthood for attenuated forms. Colon resection surgery is recommended if numerous colon polyps are found due to high risk of early death from colon cancer. International polyposis registries exist that track known cases of FAP or APC gene defects, for research and clinical purposes. Mutation of APC also occurs commonly in incident cases of colorectal carcinoma, emphasizing its importance in this form of cancer.
Familialadenomatouspolyposis (FAP) is an autosomal dominant inherited condition in which numerous adenomatous polyps form mainly in the epithelium of...
Adenomatouspolyposis coli (APC) also known as deleted in polyposis 2.5 (DP2.5) is a protein that in humans is encoded by the APC gene. The APC protein...
Attenuated familialadenomatouspolyposis is a form of familialadenomatouspolyposis, a cancer syndrome. It is a pre-malignant disease that can develop...
polyps. The condition has been described both in patients with familialadenomatouspolyposis (FAP) and attenuated variants (AFAP), and in patients in whom...
generations One or more colon cancers diagnosed under age 50 years Familialadenomatouspolyposis (FAP) has been excluded The Amsterdam II criteria were developed...
disorders that can cause colorectal cancer include familialadenomatouspolyposis and hereditary non-polyposis colon cancer; however, these represent less than...
to decrease the risk of colorectal adenomas in people with familialadenomatouspolyposis. It is taken by mouth. Benefits are typically seen within an...
malformation. Familialadenomatouspolyposis (FAP) is a familial cancer syndrome caused by mutations in the APC gene. In FAP, adenomatous polyps are present...
Rectal discharge is intermittent or continuous expression of liquid from the anus (per rectum). Normal rectal mucus is needed for proper excretion of waste...
Epithelial / Mesenchymal Type."[citation needed] Individuals with familialadenomatouspolyposis (FAP), a syndrome of early-onset colonic polyps and adenocarcinoma...
surgical removal include Crohn's disease, ulcerative colitis, familialadenomatouspolyposis, and total colonic Hirschsprung's disease. An ileostomy may...
colorectal cancer. Its histology is usually adenocarcinoma. Familialadenomatouspolyposis (FAP), Gardner syndrome, Lynch syndrome, Muir–Torre syndrome...
disorders that can cause colorectal cancer include familialadenomatouspolyposis and hereditary non-polyposis colon cancer; however, these represent less than...
nonglandular areas but express glandular tissue structure (as can happen in familialpolyposis coli). Although adenomas are benign, they should be treated as pre-cancerous...
gland polyposis is a medical syndrome with multiple fundic gland polyps. The condition has been described both in patients with familialadenomatous polyposis...
fatal. Most cases are sporadic, but some are associated with familialadenomatouspolyposis (FAP). Approximately 10% of individuals with Gardner's syndrome...
disease. It is also the treatment of choice for patients with familialadenomatouspolyposis. According to the guidelines published by the American Society...
multiple endocrine neoplasia type 4 (MEN4 gene), Carney complex, and Familial isolated pituitary adenoma (FIPA). Despite their frequent association with...
BRCA2 and PALB2 genes; hereditary non-polyposis colon cancer (Lynch syndrome); and familialadenomatouspolyposis. PanNETs have been associated with multiple...
physiological conditions, suitable for testing therapeutics. FamilialAdenomatousPolyposis (FAP) is a hereditary disease that is characterized with development...
peripheral tumors. In intra-abdominal fibromatosis associated with familialadenomatouspolyposis (FAP), surgery is avoided if possible due to high rates of recurrence...
"radical behaviorist" position Familialadenomatouspolyposis, a condition where polyps form in the large intestine Familial amyloid polyneuropathy, a neurodegenerative...
develop the neoplasia type. *- of patients with MEN1 and gastrinoma FMTC = familial medullary thyroid cancer MEN 2B is sometimes known as MEN 3 and the designation...
appearance and are referred to as pseudopolyps. Polyposis syndromes, such as familialadenomatouspolyposis, could give rise to a similar appearance on imaging...
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