Evaluation of EGF61A/g and egf61380a polymorphisms in patients with irritable bowel syndrome

Irritable bowel syndrome (IBS) is a prevalent and important member of the family of functional intestinal disorders that is associated with decreased quality of life. No additional diagnostic methods or laboratory parameters have been defined for IBS other than the Roma IV criteria. Also, no studies have been performed to determine the importance of EGF polymorphisms in the diagnosis of IBS. Therefore, in a group of IBS patients EGF61 A/G and EGF G1380A genetic polymorphisms were examined and compared with those of controls. A total of 100 IBS patients diagnosed on the basis of Roma IV criteria and 100 otherwise healthy controls with no known medical conditions were included. Of the IBS patients, 61%, 22%, and 17% had constipation-dominant (IBS-C), mixed (IBS-M), and diarrhea-dominant (IBS-D) IBS. Complete blood count, lipid profile, thyroid function tests, and biochemical parameters were examined in all participants. EGF 1380 A/G and +61A/G polymorphisms were examined using PCR-RFLP methodology after obtaining 5 ml of blood sample from each participant. The frequency of these polymorphisms were compared between the two groups in order to assess their role in distinguishing patients from healthy controls. Also, IBS sub-groups were compared with regard to differences in these polymorphisms. In terms of gender distribution, there were more male patients in IBS group than in the control group (36% vs. 19%, p=0.007). Other parameters with a statistically significant difference between the two groups included hemoglobin (14.0 ± 1.5 g/dl vs 13.1 ± 1.8 g/dl, p < 0.001), ALT (24 ± 13 U/L vs. 19 ± U/L, p=0.001), and total bilirubin (0.8 ± 1.4 mg/dl vs. 0.5 ± 0.3 mg/dl, p=0.03). When IBS subgroups were compared, a significant difference in GGT was found between IBS-C and IBS-M subgroups (32 ± 34 U/L vs. 14 ± 5 U/L, p=0.02), as well as in albumin levels between IBS-M and IBS-D subgroups (4.6 ± 0.2 U/L vs. 4.4 ± 0.2 U/L, p=0.03). Comparison of EGF G1380A allele and genotype frequency showed a 28-fold higher incidence of Genotype A/G among IBS patients than controls (65% vs. 6%, OR 28.4; 95% CI: 11.3-71.6, p<0.001). Also, EGF 61 A/G genotype frequency was significantly different between IBS-C and IBS-M patients (p=0.01), and between IBS-M and IBS-D patients (p=0.04). However, there were no significant differences between IBS-C and IBS-D in this regard (p=0.37). Our findings showed a significantly higher occurrence of EGF G1380A polymorphism among IBS patients, suggesting that this polymorphism be used as a diagnostic tool for IBS in the future with a high negative predictive value. Furthermore, EGF 1380 +61A/G polymorphism may assist in differentiating between IBS subgroups. Our results should be corroborated in larger series. Keywords: IBS, EGF G1380A polymorphism, EGF 61 A/G polymorphism, EGFR.