Mo2044 Irritable Bowel Syndrome, Serotonin Transporter 5HTTLPR Polymorphism and Psychopathological Traits: Dangerous Relations?

The involvement of serotonin in the pathophysiology of irritable bowel syndrome (IBS) as well as the frequent concomitance of psychological/psychiatric disorders are well known. The promoter of human SERT gene contains a polymorphism (5HTTLPR: 44-bp insertion/ deletion), which gives rise to long (L) and short (S) alleles. The S allele causes a decreased SERT expression, resulting in a reduced efficiency of serotonin reuptake. However few data are available about the possible correlations of IBS, psychological/psychiatric disorders and the 5HTTLPR polymorphism. The present study evaluates the possible association between the severity of gastrointestinal symptoms and psychopathological traits in IBS patients relating to 5HTTLPR polymorphism. 77 IBS patients (20 m, 57 f; mean age 41.2 years) were consecutively enrolled according to Rome III criteria: 40 with diarrhea predominant (DIBS), 22 constipation predominant (C-IBS) and 15 mixed (M-IBS) bowel habit. Symptom severity was estimated by IBS-SSS questionnaire. Genomic DNA was extracted from saliva and the SERT gene region containing the 5HTTLPR polymorphism was amplified by polymerase chain reaction. Presence of psychopathological disorders was evaluated by the means of specific questionnaires: CGI, MADRS, HAM-A. Sexual disfunction was evaluated by ASEX score. A significant correlation between IBS-SSS and the severity of psychopathological disorders evaluated by using CGI, MADRS and HAM-A scores was found (Rho Spearman 0.39, 0.47, 0.44 respectively, p,0.01). There was no significant correlation between IBSSSS and the severity of sexual dysfunction evaluated by ASEX (Rho Spearman 0.10). L/L genotype was reported in 25 (32.46 %) subjects, L/S genotype in 41 (53.24 %) subjects and S/S genotype in 11 (14.28 %) subjects. IBS-SSS and psychopathological features were not different in the L/L, L/S and S/S genotypes (Anova and Rho Spearman). A significant correlation between the severity of IBS symptoms and the severity of psychopathological impairment, depression and anxiety was found. This correlation does not seem to be influenced by 5HTTLPR polymorphism.