Familial adenomatous polyposis syndromes

Last reviewed: 6 Jan 2023
Last updated: 06 Apr 2022



History and exam

Key diagnostic factors

  • family history of FAP/attenuated FAP
  • teenager
  • onset of colorectal cancer in middle age
  • bilateral pigmentation of the retina
More key diagnostic factors

Other diagnostic factors

  • constipation/diarrhoea
  • haematochezia
  • extraintestinal features of FAP
Other diagnostic factors

Risk factors

  • germline APC gene mutation
  • family history of FAP or attenuated FAP
More risk factors

Diagnostic investigations

1st investigations to order

  • colonoscopy
  • extended-side-viewing oesophagogastroduodenoscopy (EGD)
More 1st investigations to order

Investigations to consider

  • genetic testing
  • abdominal imaging with CT or MRI
More investigations to consider

Treatment algorithm


FAP: surgery acceptable to patient

FAP: patient averse to immediate surgery with no contraindications to delayed surgery

attenuated FAP



Priyanka Kanth, MD, FACG

Associate Professor

Internal Medicine

University of Utah

Salt Lake City



PK is a co-investigator for multicentre clinical trials in familial adenomatous polyposis funded by the National Cancer Institute and Janssen Pharmaceutica.


Dr Priyanka Kanth would like to gratefully acknowledge Dr Charles A. Ternent, Dr Alan G. Thorson, Dr Lisa A. Boardman, and Dr Douglas L. Riegert-Johnson, the previous contributors to this topic.


CAT, AGT, LAB, and DLRJ declare that they have no competing interests.

Peer reviewers

Yann Parc, MD, PhD

Professor of General Surgery

Department of Digestive Surgery

Hopital Saint-Antoine

Universite Pierre et Marie Curie Paris VI




YP declares that he has no competing interests.

Gabriela Moslein, MD

Editorial Board

Allgemein- und Viszeralchirurgie

St Josefs-Hospital Bochum-Linden




GM declares that she has no competing interests.

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