Familial Adenomatous Polyposis (FAP)

Familial adenomatous polyposis (FAP) is a rare, inherited disorder characterized by the development of hundreds to thousands of polyps in the colon and rectum. These polyps are typically benign (non-cancerous), but they have a high potential to become malignant (cancerous) over time.

Causes and Risk Factors

FAP is caused by a mutation in the APC gene, which is responsible for regulating cell growth and division. This mutation leads to the formation of multiple adenomatous polyps in the colon and rectum. The condition is inherited in an autosomal dominant pattern, meaning that a single copy of the mutated gene is enough to cause the disorder.

Symptoms

The symptoms of FAP may include:

• Blood in the stool or black, tarry stools
• Diarrhea or constipation
• Abdominal pain or cramping
• Weight loss or fatigue
• Anemia (low red blood cell count)

Diagnosis

The diagnosis of FAP is typically made through a combination of the following tests:

• Colonoscopy: a procedure that uses a flexible tube with a camera to visualize the inside of the colon and rectum
• Genetic testing: a blood test that checks for mutations in the APC gene
• Biopsy: a procedure that removes a sample of tissue from a polyp for examination under a microscope

Treatment

The treatment of FAP typically involves:

• Surgical removal of the colon and rectum (colectomy) to prevent cancer from developing
• Regular surveillance with colonoscopy to monitor for new polyps or cancer
• Removal of polyps (polypectomy) during colonoscopy

Complications

If left untreated, FAP can lead to the development of colorectal cancer. Other complications may include:

• Intestinal obstruction or blockage
• Bleeding or anemia from polyps
• Malnutrition or weight loss due to malabsorption

Prevention

There is no way to prevent FAP, but regular surveillance and early treatment can help reduce the risk of complications. Individuals with a family history of FAP should undergo genetic testing and regular colonoscopy screenings starting at a young age.