In this pilot exploratory study, the primary aim was to determine whether genetic polymorphisms of tryptophan hydroxylase ( TPH1/TPH2), serotonin reuptake transporter ( SERT), or catechol-O-methyltransferase ( COMT) are associated with fatigue in women with IBS.
In contrast, compared with control subjects, COMT 158Met was significantly more prevalent in the IBS group (P=0.040) and significantly more prevalent in patients with diarrhea (P=0.029).
In a regression model, the number of methionine alleles in COMTval158met was linearly related to placebo response as measured by changes in IBS-SSS (p = .035).
In this study we found an association between the val/val genotype of the val158metCOMT gene and IBS as well as to specific IBS related bowel pattern in IBS patients.