1. © 2009 NHS National Genetics Education and Development Centre Genetics and Genomics for Healthcare
www.geneticseducation.nhs.uk
Inherited Pre-disposition to Bowel
CancerFamilial Adenomatous Polyposis (FAP)
This PowerPoint file contains a number of slides that may be useful for teaching of
genetics concepts.
You may use these slides and their contents for non-commercial educational purposes.

2. © 2009 NHS National Genetics Education and Development Centre Genetics and Genomics for Healthcare
www.geneticseducation.nhs.uk
Familial Adenomatous Polyposis
This presentation includes:
The genetic development of familial cancer (2 hit hypothesis)
• A pedigree showing FAP in a family
• A clinical photograph of a piece of resected bowel with multiple polyps
• Two pedigrees used to assess risk and highlight which relatives are ‘at risk’ and
need bowel screening
• Surveillance/Screening for FAP

3. © 2009 NHS National Genetics Education and Development Centre Genetics and Genomics for Healthcare
www.geneticseducation.nhs.uk
The genetic basis of the dominantly inherited familial cancer syndromes
An altered allele is inherited and is found in all body cells that contain genetic material. When the second
(previously normal) allele of the gene pair becomes inactivated in a particular somatic cell, this can lead to loss
of control of cell growth and unchecked cell proliferation.
Clone of cancer cells from
this one cell
Inherited
altered allele
Second allele of the pair becomes
inactivated (somatic mutation)

4. © 2009 NHS National Genetics Education and Development Centre Genetics and Genomics for Healthcare
www.geneticseducation.nhs.uk
Fig. 12.2 ©Scion Publishing Ltd
Photo. courtesy of Medical Illustration, Manchester Royal Infirmary
Familial adenomatous polyposis coli
(a) Pedigree of the Xenakis family.
(b) Part of a surgically resected colon with polyps.

5. © 2009 NHS National Genetics Education and Development Centre Genetics and Genomics for Healthcare
www.geneticseducation.nhs.uk
Martin’s family
d. 34yrs
Martin Suzanne
Jamie
12
Sophie
9
Alex
5
36
(colectomy @ 25) Who is at risk?

6. © 2009 NHS National Genetics Education and Development Centre Genetics and Genomics for Healthcare
www.geneticseducation.nhs.uk
Martin’s family
d. 34yrs
Martin Suzanne
Jamie Sophie Alex
12 9 5
36
(colectomy @ 25)
Who is at risk?

7. © 2009 NHS National Genetics Education and Development Centre Genetics and Genomics for Healthcare
www.geneticseducation.nhs.uk
Surveillance for FAP
• Annual sigmoidoscopies from age 10 to 12.
• Colonoscopies once polyps detected.
• Surveillance of remaining gut following colectomy.
• http://www.nice.org.uk/nicemedia/pdf/CSGCCfullguidance.pdf
Is there an alternative? Genetic testing