16993 Familial Adenomatous Polyposis Fap

Overview

Familial adenomatous polyposis, often called FAP, is a rare inherited condition that causes hundreds or thousands of small growths called polyps to form in the large intestine (colon). These polyps are not cancer at first, but over time they can turn into cancer if not treated.

No. FAP is rare. It affects around 1 in every 8,000 to 10,000 people worldwide.

FAP affects men and women equally. Polyps usually start to appear during the teenage years, and if the condition is not found, bowel cancer often develops by the 40s. In some families, children are diagnosed earlier because of a known family history.

Symptoms

Common symptoms

• Often there are no early symptoms — this is why screening is important.
• Blood or mucus in the stool (poo)
• Diarrhoea or a change in bowel habits that lasts more than a few weeks
• Feeling very tired (fatigue)
• Abdominal pain or cramping
• Unexplained weight loss

Symptoms in children

• Children with FAP often have no symptoms until their teens.
• Some children may develop a harmless mark on the back of the eye (called congenital hypertrophy of the retinal pigment epithelium, or CHRPE) that an eye specialist can see before polyps appear.
• Occasionally, a child may have stomach pain, a change in bowel habits, or blood in the stool.

Symptoms in older adults

• In adults who have not been diagnosed or treated, symptoms can include long-term blood loss leading to anaemia (low iron in the blood), a change in bowel habits, abdominal pain, and unintentional weight loss.
• These symptoms can also be signs of bowel cancer, so it is important to see a doctor promptly.

Causes

Main causes

• FAP is caused by a change (mutation) in the APC gene, which normally helps control cell growth in the large intestine.
• The gene change is usually inherited from a parent, and each child of a parent with FAP has a 50% chance of inheriting it.
• In about 20% of people with FAP, there is no family history — the gene change happens for the first time in that person.

Risk factors

• Having a parent or sibling with FAP
• Having a parent with the APC gene mutation
• Being born into a family where FAP is known to occur

When to see a doctor

See a doctor urgently if:

• Call your local emergency number if you have severe belly pain, heavy rectal bleeding, or signs of a blocked bowel (cramping, bloating, and an inability to pass gas or stool).
• See a doctor the same day if you notice blood in your stool, or if you have worsening symptoms with fever.

Book a routine appointment if:

• Make an appointment if you have a family history of FAP, even if you feel well.
• Talk to your doctor if you have persistent bowel changes, blood in your stool, or unexplained tiredness.
• Ask your GP about genetic counselling if FAP runs in your family.

Diagnosis

Doctors diagnose FAP using a combination of family history, genetic blood tests, and looking inside the colon with a camera (colonoscopy). If a close relative has FAP, genetic testing can tell you whether you carry the changed gene well before polyps cause symptoms.

Tests that may be done

• Genetic test — a blood sample checks for changes in the APC gene.
• Colonoscopy — a flexible tube with a camera is used to examine the whole large intestine and count polyps.
• Sigmoidoscopy — an exam of the lower part of the colon, sometimes used to confirm a suspected diagnosis.
• Upper endoscopy — a test to look for polyps in the stomach and upper small intestine, which can also occur in FAP.
• Eye exam — looks for the harmless retinal marks (CHRPE) that can appear in children with FAP.

What to expect at your appointment

If you are being checked for FAP, you will be referred to a specialist team that may include a gastroenterologist, genetic counsellor, and specialist nurse. The team will explain the tests, what the results mean, and help you plan surveillance and treatment. You will not be alone in making these decisions.

Treatment

The goal of treatment for FAP is to prevent polyps from turning into cancer. Treatment plans are individual and usually involve regular surveillance to count and remove polyps, and - for many people - a planned operation to remove the large intestine once polyps become too numerous to manage safely.

Self-care at home

• Keep all your appointments for colonoscopy and other surveillance tests — they are the best way to stay ahead of polyps.
• For children and teenagers, help them understand why regular check-ups are needed.
• Eat a balanced diet, keep physically active, and avoid smoking.

Medical treatments

Some medicines may be used to help reduce the number of polyps, but they are not a cure and do not replace surgery. These medicines should only be considered after discussion with your specialist team. Doctors may also use a special camera test to remove individual polyps during endoscopy. If polyps are widespread, surgery is usually recommended.

When is surgery considered?

Surgery to remove the colon (colectomy) is the most reliable way to prevent bowel cancer in FAP. The timing depends on the number and size of polyps, your age, and your overall health. Most people have surgery in their late teenage or early adult years. Your surgeon will discuss the options, including surgery that may avoid the need for a permanent stoma (bag).

Living with this condition

Living with FAP means building a routine of regular check-ups, knowing what symptoms to look for, and working closely with your medical team. It can be stressful, but many people manage very well and live full, active lives.

Lifestyle tips

• Attend every scheduled surveillance appointment.
• Tell your specialist about any new symptoms, such as abdominal pain, bleeding, or changes in bowel habits.
• Encourage children and young adults to stay active and eat well.
• Connect with a support group — talking to others with FAP can be very reassuring.

Diet and exercise

There is no special diet that cures FAP, but eating plenty of fruits, vegetables, and whole grains and staying physically active help keep your bowel healthy and support your overall wellbeing. After surgery, your medical team will give you tailored guidance on eating and hydration.

Mental health and emotional wellbeing

Learning that you or your child has an inherited condition like FAP can cause worry, anxiety, or fear about cancer. These feelings are normal. It is important to talk about them, and to ask for professional counselling if they start to affect daily life.

Prevention

You cannot prevent the genetic mutation that causes FAP. But you can prevent the complications of FAP, especially bowel cancer, by having regular screening and following your specialist's recommendations about surgery.

Screening programmes

Screening for FAP begins early. If a child is at risk, genetic testing and a first colonoscopy are usually recommended in the early teenage years. Once FAP is diagnosed, colonoscopy is repeated every 1 to 2 years, along with regular upper endoscopy to check the stomach and small intestine.

Complications

If left untreated

• Bowel (colorectal) cancer develops in almost all people with FAP if the colon is not removed.
• Polyps can also arise in the stomach and small intestine, which carry a smaller but real risk of cancer over time.
• Desmoid tumours — non-cancerous growths of connective tissue — occur in about 10-15% of people with FAP and can sometimes cause problems if they press on other organs.
• Anaemia from chronic bleeding, and bowel blockage or obstruction due to many polyps.

Long-term outlook

The outlook for people with FAP is very good when the condition is found early and managed carefully. With modern screening and surgery, most people with FAP can prevent bowel cancer and live a normal lifespan. Regular check-ups are the key to staying well.

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