Familial Adenomatous Polyposis Definition
Familial Adenomatous Polyposis (FAP) is a rare genetic condition characterized by the development of extra tissues or polyps in the large intestine and the duodenum (upper region of the small intestine) of an individual. The polyps generally develop in the epithelium. If left untreated, the polyps growing within the large intestine are likely to turn cancerous by the time a patient reaches 40 years of age. Individuals with FAP are usually most at risk of developing colon cancer.
It is usually treated with surgery. However, substances like curcumin and quercetin present in certain plant extracts have recently been proved to be useful in the management of the polyps.
It is often referred to by various other names, which include:
- Familial Polyposis Coli
- Gardner Syndrome
- Adenomatous Polyposis Coli
- Adenomatous Polyposis of the Colon
- Colon cancer, familial
- Familial Intestinal Polyposis
- MYH-Associated Polyposis
- Familial Multiple Polyposis
- Familial Multiple Polyposis Syndrome
- Polyposis Coli
- Familial Polyposis Syndrome
- Hereditary Polyposis Coli
- Turcot Syndrome
Familial Adenomatous Polyposis Causes
FAP is a hereditary condition caused by certain gene mutations. However, the exact factors that trigger these mutations are still not known. According to researches, factors like diet and lifestyle may also contribute to this disorder. However, inheriting the defective gene is the principal cause of development of these polyps.
Familial Adenomatous Polyposis Genetics and Inheritance Pattern
There can be different genetic causes for the disease and it can be inherited in various inheritance patterns. Sometimes, FAP results from APC gene mutation and is inherited in an autosomal dominant pattern. In other words, inheriting only a single copy of the abnormal gene from one parent can lead to the condition. This type of Polyposis Coli is likely to become malignant in almost all of the cases. Individuals with APC gene mutation usually have one parent with the disease.
Mutations in MUTYH gene are another known cause of FAP. This type of genetic mutation follows the autosomal recessive pattern, meaning that one has to inherit two copies of the abnormal gene for developing the disorder. In most cases, both parents of a child inheriting Gardner Syndrome in an autosomal recessive pattern are asymptomatic carriers of the gene mutation.
Familial Adenomatous Polyposis Symptoms
It is possible to have multiple polyps in the intestine without them being evident. In such cases, patients start having the symptoms when the condition reaches a more serious stage. Sometimes, the symptoms do not develop until the polyps have already reached a cancerous stage. Its common symptoms are:
- Blood and/or mucus in stool
- Change in normal bowel habits, lasting for over six weeks
- Abdominal pain
- Sudden weight loss without any obvious reason
- Pigmented lesions of retina (congenital hypertrophy of the retinal pigment epithelium or CHRPE)
- Sebaceous cysts
- Jaw cysts
- Osteomata or benign bone tumors
Sometimes, a patient may not show any visible sign of blood loss. However, iron deficiency may gradually lead to anemia. The polyps may metastasize to other organs, such as the liver, if left untreated.
What is Attenuated Familial Adenomatous Polyposis?
Attenuated Familial Adenomatous Polyposis, or Attenuated FAP, is a different form of the disorder. Individuals having fewer than one hundred adenomatous polyps, which tend to grow on the right side of the colon, are said to have attenuated FAP. The average number of polyps in this disorder is around 30. Various health problems associated with the classic FAP also occur in the attenuated form. FAP patients are more at risk of developing colon cancer. However, the diagnosis is not generally done until one becomes 50 to 55 years old.
Familial Adenomatous Polyposis Prevention
Currently, there is no preventive measure for FAP. This is due to the fact that its underlying causes are unknown. Scientists are trying to find out whether it is possible to avoid the occurrence of this condition by preventing the gene mutation. Some preliminary studies have been conducted to discover the usefulness of cyclooxygenase antagonists (Celebrex or Vioxx) in preventing the development of the colorectal polyps. However, the effects of these drugs on the growth of the cancerous polyps are still not clearly known.
Genetic counseling and genetic testing can help to determine the chances of developing the polyps. Couples with a family history of FAP should consider genetic testing and gene reviews to learn whether they are carrying the abnormal gene. This helps to understand the possibility of having a child with this disease.
Familial Adenomatous Polyposis Screening
Children with a family history of FAP are regularly examined for any signs of polyps in their intestines. The screening tests allow physicians to detect the earliest symptoms, which makes it possible to start the treatment at an early stage. Doctors also perform tests for detecting other signs of FAP, such as alterations in the backside of the eyes.
Doctors may stop the screening process if the exams show that an individual does not have any mutated gene.
The disease can also occur in people without any family history of the gene mutations. In such cases, the bowel symptoms are the first indicators of the presence of the polyps.
Familial Adenomatous Polyposis Diagnosis
The diagnosis may vary from one patient to another and involves various tests and examinations. The most common diagnostic procedure used for the purpose is colonoscopy. Patients having more than 100 polyps in their intestine are considered to be suffering from FAP. The following tests can be used for making the diagnosis:
In colonoscopy, a flexible tube is used for examining the entire colon of the patient. The tiny camera attached to the tube allows a doctor to see the insides of the intestine of the patient on a screen.
This screening test is similar to colonoscopy. A flexible tube, with a small video camera attached to it, is inserted into the rectum of the patient for observing the sigmoid (the lower part of the colon). Sigmoidoscopy is very useful for detecting any polyps in the sigmoid and also helps to determine whether or not the polyps are malignant.
Side-Viewing Esophagogastroduodenoscopy or EGD
It is used for examining the esophagus, stomach and duodenum of an individual. In some cases, a diagnostician may collect a biopsy (small tissue sample) for further study.
Exams like computed tomography or CT scan and magnetic image resonance or MRI are often used for confirming the diagnosis. These tests help a doctor to evaluate desmoid tumors by producing images of the pelvis and abdomen.
Sometimes, a diagnostician may collect a biopsy of the polyps during endoscopy and send it to a laboratory for further testing. Biopsy helps to determine whether or not the polyps are malignant.
In some cases, blood tests may help to determine the location of the genetic mutation. Blood tests are particularly helpful for detecting mutations in APC gene.
Familial Adenomatous Polyposis Associated Cancers
The polyps in the intestine can lead to various forms of cancers including:
- Small bowel or intestinal cancer
- Colorectal cancer
- Papillary thyroid cancer
- Pancreatic cancer
- Adrenal gland cancer
- Brain or CNS tumor
- Bile duct cancer
- Stomach cancer
Familial Adenomatous Polyposis Differential Diagnosis
While diagnosing FAP, it is important to rule out the presence of the following disorders that give rise to similar symptoms:
- Peutz-Jeghers Syndrome
- Hereditary Mixed Polyposis
- Hereditary Non-Polyposis Colorectal Cancer
- Juvenile Polyposis
- MUTYH Polyposis
- Inflammatory Polyposis
- Cowden Disease
- Nodular Lymphoid Hyperplasia
Familial Adenomatous Polyposis Treatment and Management
The treatment of FAP depends on the stage of the condition and the severity of its symptoms. In most cases, surgical intervention is required to keep the polyps from becoming cancerous. However, these surgeries are not able to cure the disease completely. Due to this reason, some medications and other follow-up care may also be needed to prevent the polyps from growing again.
Various surgical procedures are used for this treatment. The following surgeries are most commonly used for curing FAP:
Total colectomy and IRA (Ileorectal Anastamosis)
Individuals with a small number of polyps are treated in this procedure. The colon of a patient is removed by a surgeon during the operation. Only five inches of rectum are left after removing the colon. The ileum or small intestine is then surgically joined with the upper rectum. The bowel functions of the patient become normal after the surgery.
Colectomy with ileoanal pouch (Restorative Proctocolectomy)
It can be very effective for treating some selective cases of FAP. In this surgery, the colon and rectum are removed while a surgeon leaves the anal sphincter muscles and the anal canal. A new rectum is then created by the surgeon using the small intestine and is attached to the patient’s anal canal. A temporary opening, called a stoma or ileostomy, may be created in the abdomen. The stoma is closed after the first operation heals properly, restoring normal bowel function.
Proctocolectomy and ileostomy
It is a relatively complicated procedure compared to the aforementioned surgeries. It is recommended only for individuals with rectal cancer as they cannot be treated by other operations. In proctocolectomy and ileostomy, both the rectum and the colon are removed and a surgeon creates a permanent ileostomy in the abdomen. After surgery, patients have to wear a bag in which the wastes can collect after leaving the body through the stoma.
It is possible to successfully remove the polyps with the removal of the colon. However, it is not possible to prevent the growth of new polyps in the intestine of the patient even after the surgery. Due to this reason, patients are often prescribed certain medications that help to control the growth of these colorectal polyps. Affected individuals should undergo regular medical checkups while taking these medications. Sulindac, an anti-inflammatory medicine, was first found to be useful for shrinking colon polyps in FAP patients. It is a nonsteroidal anti-inflammatory drug (NSAID) commonly used for treating arthritis. However, the medicine has not been approved by the Food and Drug Administration (FDA).
Another anti-arthritis medicine known as celecoxib has been approved by the FDA to be used for the purpose of shrinking the polyps resulting from Gardner Syndrome. A daily dosage of 400 mg can effectively control the development of polyps in the colon and rectum.
Familial Adenomatous Polyposis Prognosis
Patients have a great risk of developing colon cancer unless prophylactic colectomy surgery is performed. Individuals with this surgery and regular screening for the development of duodenal polyposis have a positive prognosis. In families with a history of FAP, individuals undergo screening from a very early age for signs of polyps in their intestine. This makes it possible for those with the condition to have the earliest treatment and a good outcome. People may also develop Gardner Syndrome due to new gene mutation. In these cases, the diagnosis and treatment can only be done after the symptoms start occurring which may result in a relatively negative prognosis.
Familial Adenomatous Polyposis Life Expectancy
It is a potentially fatal disease, which may cause the death of patients if left untreated. However, prophylactic total proctocolectomy surgery and proper screening help sufferers to have a long life expectancy. Still, AFP patients are likely to die at a younger age compared to healthy people. The morbidity related to this disorder has various causes, including duodenal/periampullary malignancy, perioperative complications and desmoids.
Familial Adenomatous Polyposis Incidence
FAP is a rare condition. Only 1 in 7,000 to 1 in 22,000 individuals are affected by it. According to its prevalence statistics, approximately 30% of all cases of FAP occur due to new mutations in the APC gene.
Familial Adenomatous Polyposis Support Groups
Various foundations and organizations provide facts and guidelines regarding the ways to fight FAP. These include:
Familial GI Cancer Registry
Mt. Sinai Hospital
Joseph and Wolf Lebovic Health Complex
600 University Avenue, Toronto
Ontario, M5T 3L9
Fax: (416) 586-5924
Tel: (416) 596-4200 ext. 8334
Johns Hopkins Hereditary Colorectal Cancer Registry
Johns Hopkins Hospital
1830 East Monument Street
Baltimore, Maryland 21205
Southeastern Hereditary Colorectal Cancer Registry
1350 Walton Way
Augusta, Georgia 30910-3599
United States of America
American Cancer Society, Inc.
1599 Clifton Road NE
Atlanta, Georgia 30329
United States of America
FAP is potentially life threatening. However, it can be corrected with proper surgical procedure and medications. With early treatment, patients can have a relatively normal life although they have to remain under constant observation for any sign of recurrence for the rest of their lives.
Familial Adenomatous Polyposis Pictures
The following pictures show how the intestine appears when affected by these polyps.
Picture 1 – Familial Adenomatous Polyposis
Picture 2 – Familial Adenomatous Polyposis Image
Table Of Content:
- Familial Adenomatous Polyposis Definition
- Familial Adenomatous Polyposis Causes
- Familial Adenomatous Polyposis Genetics and Inheritance Pattern
- Familial Adenomatous Polyposis Symptoms
- What is Attenuated Familial Adenomatous Polyposis?
- Familial Adenomatous Polyposis Prevention
- Familial Adenomatous Polyposis Screening
- Familial Adenomatous Polyposis Diagnosis
- Familial Adenomatous Polyposis Associated Cancers
- Familial Adenomatous Polyposis Differential Diagnosis
- Familial Adenomatous Polyposis Treatment and Management
- Familial Adenomatous Polyposis Prognosis
- Familial Adenomatous Polyposis Life Expectancy
- Familial Adenomatous Polyposis Incidence
- Familial Adenomatous Polyposis Support Groups
- Familial Adenomatous Polyposis Pictures