Systematic Reviews
Copyright ©The Author(s) 2018. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Meta-Anal. Feb 26, 2018; 6(1): 1-8
Published online Feb 26, 2018. doi: 10.13105/wjma.v6.i1.1
Genetic studies in irritable bowel syndrome-status quo
Stefan-Lucian Popa, Dan L Dumitrascu, Romana Vulturar, Beate Niesler
Stefan-Lucian Popa, Dan L Dumitrascu, Department of 2nd Medical, “Iuliu Hatieganu” University of Medicine and Pharmacy, Cluj-Napoca 400006, Romania
Romana Vulturar, Department of Cell and Molecular Biology, “Iuliu Hatieganu” University of Medicine and Pharmacy, Cluj-Napoca 400006, Romania
Beate Niesler, Department of Human Molecular Genetics, Heidelberg University, Heidelberg 69120, Germany
Author contributions: Popa S supervised the study and has made substantial contributions to conception and correction of the drafts; Dumitrascu DL analyzed the data and drafted the paper; Vulturar R has made substantial contributions to conception and revised the drafts; Niesler B made substantial contributions to the analysis of the data, interpretation, and revised the drafts.
Conflict-of-interest statement: No potential conflicts of interest relevant to this article were reported.
Data sharing statement: No additional data are available.
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:
Correspondence to: Dr. Dan L Dumitrascu, PhD, Full Professor, Department of 2nd Medical, “Iuliu Hatieganu” University of Medicine and Pharmacy, Clinicilor Street nr3-5, Cluj-Napoca 400006, Romania.
Telephone: +40-26-4593355
Received: December 3, 2017
Peer-review started: December 4, 2017
First decision: December 27, 2017
Revised: January 17, 2018
Accepted: February 24, 2018
Article in press: February 25, 2018
Published online: February 26, 2018
Research background

The irritable bowel syndrome (IBS) is a hot topic and the uncovering its genetic determination is very important.

Research motivation

Knowing the genetic link in the occurrence of IBS could offer the perspective to better know this condition and to improve its management.

Research objectives

In order to shed light on this topic, we carried out a systematic review of the data on main genetic polymorphisms described uptoday.

Research methods

A PubMed search was carried out in September 2016, looking for studies analyzing the association between gene polymorphisms and IBS. Search keywords were: IBS and gene polymorphism. The inclusion criteria were: original articles that included patients with IBS-C, IBS-D or IBS-M, and that studied genetic polymorphisms in IBS patients. Exclusion criteria were: reviews, lack of abstract, non-English publications.

Research results

The result of our study was a review of 12 polymorphisms, residing in 10 genes reported to be associated with the pathogenesis and the pathophysiology of IBS. The main problem that remains to be solved in the current genetic studies analysing IBS is represented by the low number of subjects included in the majority of studies.

Research conclusions

High-quality evidence for the relation between genetic polymorphisms and the IBS etiology is lacking, as a result of the insufficient number of high-quality prospective studies. Similar studies on functional gastrointestinal disorders and genetic polymorphisms are also very limited. The strength of articles, included in this review are the determination of each genetic polymorphism, using high efficiency techniques. The polymorphisms of the Serotonin transporter (SERT or SLC6A4) gene were the most frequent genetic polymorphisms studied in this pathology. Investigation of PI-IBS patients showed associations with TNFSF15 genetic polymorphisms which also predispose to Crohn’s disease suggesting a possible common underlying pathogenesis.

Research perspectives

From the genetic perspective, the actual IBS subgroups are not sufficient in order to identify distinct phenotypes and further in leading to new guiding principles for treatment. These limitations can be overcome by international cooperation, like the GENIEUR network (Genes in Irritable Bowel Syndrome Research Network Europe), who allows the contribution of specialists from many countries and the collecting of large samples of subjects who are deeply phenoytped to allow genotype phenotype correlation and data mining approached. Such studies allow also the standardization of investigative tools in the approach of IBS patients.