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Familial adenomatous polyposis: two different APC gene mutations in two unrelated Arab families with differing response to genetic counselling

Marafie, Makia J.a; Al-Elwani, Farah L.b; Al Suliman, Ibrahim S.a

Middle East Journal of Medical Genetics: January 2014 - Volume 3 - Issue 1 - p 31–36
doi: 10.1097/01.MXE.0000441099.60123.9c
Original articles

Introduction: Familial adenomatous polyposis (FAP) is an autosomal dominant condition caused by a mutation in the APC tumour-suppressor gene, located on chromosome 5q21–q22. The clinical presentation includes multiple adenomatous large bowel and rectal polyps, in childhood and adolescence. The risk of colorectal carcinoma development reaches 100% in the mutation carriers. Gardner syndrome is a phenotypic variant of FAP with extracolonic manifestations such as dental anomalies, osteomas, congenital hypertrophy of retinal pigment epithelium, desmoids tumour and varieties of extracolonic cancers. Attenuated FAP is another variant, where the condition is mild with less than 100 polyps, for which mutation in either APC or in MUTYH gene is responsible.

Patients and methods: Here we present two FAP-associated families; harbouring two different germline APC gene mutations, discuss the clinical expression and therapeutic decisions for each of their members, based on the phenotypic–genotypic findings. We also describe the attitude of high-risk counselees towards genetic counselling.

Conclusion: Early informed medical intervention will help in better decision making and cancer prevention in the family.

aKuwait Medical Genetics Centre, Maternity Hospital, Safat

bMubarak Al-Kabeer polyclinic, Mubarak Al-Kabeer Area, Kuwait

Correspondence to Makia J. Marafie, MBBCH, PhD, FRCP (Edn), Kuwait Medical Genetics Centre, Maternity Hospital, Sabah Medical Area, PO Box 5833, Safat 13059, Kuwait Tel: +965 2481 0563; fax: +965 2484 2073; e-mail: mj_marafie@yahoo.com

Received April 27, 2013

Accepted July 13, 2013

© 2014 Middle East Journal of Medical Genetics