A serotonin transporter gene (SLC6A4) polymorphism is associated with reduced risk of irritable bowel syndrome in American and Asian population: a meta-analysis.
OBJECTIVE
Association studies of serotonin transporter gene SLC6A4 I/S polymorphism and irritable bowel syndrome (IBS) have shown inconsistent and contradictory results among different populations. In the present study, meta-analysis was performed to evaluate the association between SLC6A4 I/S polymorphism and IBS susceptibility.


METHODS
Systemic assessment was performed for the published studies based on the association of SLC6A4 I/S polymorphism and IBS risk from PubMed (Medline), EMBASE search. A meta-analysis was done to appraise the said association. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for allele contrast, homozygous, heterozygous, dominant and recessive genetic model.


RESULTS
A total of twelve studies comprising 2068 IBS cases and 2076 controls were included in this meta-analysis. Overall, no significant results were obtained for S allele carrier (S vs. I: p=0.488; OR=1.073, 95% CI=0.879 to 1.311) Co-dominant (SS vs. II; p=0.587; OR=1.112, 95% CI=0.758 to 1.631), (IS vs. II; p=0.361; OR=0.878, 95% CI=0.665 to 1.160). Similarly, dominant (SS+IS vs. II: p=0.853; OR=0.974, 95% CI=0.736 to 1.288) and recessive (SS vs. II+IS: p=0.267; OR=1.172, 95% CI=0.886 to 1.522) genetic models did not demonstrate risk. In the subgroup population based analysis, reduced risks were found in American (IS vs. II: p=0.009; OR=0.685, 95% CI=0.516 to 0.908) and Asian (SS+IS vs. II; p=0.001; OR=0.116, 95% CI=0.068 to 0.197) population. However, no risk was observed in European population.


CONCLUSIONS
This investigation clearly demonstrates that SLC6A4 (Ins/Del) polymorphism is associated with reduced risk of IBS in American and Asian population. However, future well-designed studies with stratified case control and biological characterization will be needed to validate this finding.
Department of Medical Microbiology, College of Nursing and Allied Health Sciences, Jazan University, Jazan, Saudi Arabia.
Mohammed Y
MY
Areeshi
Shafiul
S
Haque
Aditya K
AK
Panda
Raju K
RK
Mandal
D000483:Alleles; D001208:Asia; D044466:Asian People; D016022:Case-Control Studies; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000235:genetics*; D009154:Mutation; D016017:Odds Ratio; D020641:Polymorphism, Single Nucleotide; D012306:Risk; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics*; D014481:United States; D044465:White People
C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins