Case Control Study
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jan 21, 2015; 21(3): 897-904
Published online Jan 21, 2015. doi: 10.3748/wjg.v21.i3.897
Genetic association of apolipoprotein E polymorphisms with inflammatory bowel disease
Ebtissam Saleh Al-Meghaiseeb, Mulfi Mubarak Al-Otaibi, Abdulrahman Al-Robayan, Reem Al-Amro, Ahmd Saad Al-Malki, Misbahul Arfin, Abdulrahman K Al-Asmari
Ebtissam Saleh Al-Meghaiseeb, Mulfi Mubarak Al-Otaibi, Abdulrahman Al-Robayan, Reem Al-Amro, Ahmd Saad Al-Malki, Department of Gastroenterology, Prince Sultan Military Medical City, Riyadh 11159, Saudi Arabia
Misbahul Arfin, Abdulrahman K Al-Asmari, Research Center, Prince Sultan Military Medical City, Riyadh 11159, Suadi Arabia
Author contributions: Al-Meghaiseeb ES, Al-Robayan A, Al-Otaibi MM, Al-Amro R and Al-Malki AS performed clinical examinations; Al-Meghaiseeb ES and Al-Robayan A collected demographic data; Al-Otaibi MM, Al-Amro R and Al-Malki AS searched the literature; Arfin M analyzed genotyping results and drafted the manuscript; and Al-Asmari AK designed the study, supervised and edited the manuscript.
Supported by KACST Project# 11-MED2204-21.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Abdulrahman K Al-Asmari, Senior Consultant and Director of Research Center, Prince Sultan Military Medical City, P.O. Box 7897, Riyadh 11159, Saudi Arabia. abdulrahman.alasmari@gmail.com
Telephone: +966-1-4777714 Fax: +966-1-4777714
Received: June 2, 2014
Peer-review started: June 3, 2014
First decision: June 27, 2014
Revised: August 28, 2014
Accepted: September 29, 2014
Article in press: September 30, 2014
Published online: January 21, 2015
Processing time: 232 Days and 5.2 Hours
Abstract

AIM: To study the association of apolipoprotein E (APOE) polymorphisms with the susceptibility of inflammatory bowel disease (IBD) in Saudi patients.

METHODS: APOE genotyping was performed to evaluate the allele and genotype frequencies in 378 Saudi subjects including IBD patients with ulcerative colitis (n = 84) or Crohn’s disease (n = 94) and matched controls (n = 200) using polymerase chain reaction and reverse-hybridization techniques.

RESULTS: The frequencies of the APOE ε2 allele and ε2/ε3 and ε2/ε4 genotypes were significantly higher in IBD patients than in controls (P < 0.05), suggesting that the ε2 allele and its heterozygous genotypes may increase the susceptibility to IBD. On the contrary, the frequencies of the ε3 allele and ε3/ε3 genotype were lower in IBD patients as compared to controls, suggesting a protective effect of APOE ε3 for IBD. The prevalence of the ε4 allele was also higher in the patient group compared to controls, suggesting that the ε4 allele may also increase the risk of IBD. Our results also indicated that the APOE ε4 allele was associated with an early age of IBD onset. No effect of gender or type of IBD (familial or sporadic) on the frequency distribution of APOE alleles and genotypes was noticed in this study.

CONCLUSION: APOE polymorphism is associated with risk of developing IBD and early age of onset in Saudi patients, though further studies with a large-size population are warranted.

Keywords: Apolipoprotein E; Polymorphism; Inflammatory bowel disease; Saudi

Core tip: This study shows apolipoprotein E (APOE) polymorphism is associated with risk of developing inflammatory bowel disease (IBD) in Saudi patients. Allele ε2 and its heterozygous genotypes increase the susceptibility to IBD, whereas the ε3 allele and ε3/ε3 genotype are protective for IBD. The APOE ε4 allele also increases the risk for IBD and is associated with early age at onset. The frequency distribution of APOE alleles and genotypes is not affected by gender or type of IBD (familial or sporadic).