Serotonin Transporter Gene Polymorphism (5-HTTLPR and VNTR) among Sudanese patients with Irritable Bowel Syndrome (IBS)

Objective: To determine the frequency of serotonin transporter gene (SERT) (5-HTTLPR) and VNTR polymorphism in patients with post infectious irritable bowel syndrome (IBS) Design: This is a cross sectional study. Setting: The study was carried out in gastroenterology outpatient clinics at Omdurman teaching hospital, Khartoum State, Sudan. Subjects: Fifty-four consecutive IBS patients between 18 and 73 years old who were referred to gastroenterology outpatient clinics and 50 apparently health controls (their age ranging from 19-68 years old) were examined and enrolled between April 2016 and April 2017. Intervention: Collection of venous blood samples Main outcome measures: Determining overall frequency of gene SERT (5-HTTLPR and VNTR) polymorphism among Sudanese IBS patients following parasitic infections. Results: SERT polymorphisms were found to be significantly increased in IBS patients in comparison with controls (P=.05), as well as patients with a family history of IBS. According to bowel habits, diarrhea (n=18) and constipation (n=26) were predominant individually, and ten patients alternated between diarrhea and constipation. We found that the 5-HTTLPR allele LL genotype occurred with greater frequency in the group with predominant diarrhea than in the other two subgroups (P=.05). Conclusion: Family history plays a major role in the presence of IBS. We found that the LS and SS genotypes are significantly correlated with IBS. No relationship was found between IBS and SERT gene polymorphism. The presence of the /S genotype in IBS patients carries an increased risk of the constipation predominant type of IBS.