Polymorphism of the promoter region of C-509T of transforming growth factor-beta1 gene and ulcerative colitis

Background: Transforming growth factor-beta is a regulatory protein that plays a key role in inflammatory, fibrotic, and immunological events in the intestinal mucosa. Recently, attention has been focused on the role of transforming growth factor-beta in the etiopathogenesis of inflammatory bowel disease. Enhanced expression of transforming growth factor-beta mRNA in the lamina propria and a disordered expression pattern of transforming growth factor-betal receptors I and 11 in epithelial cells have been documented in the colonic mucosa of patients with ulcerative colitis and Crohn's disease. Based on these associations, we report in this study, the restriction fragment length polymorphism-polymerase chain reaction and allele frequencies of the transforming growth factor-beta gene polymorphisms in a population of Iranian patients with ulcerative colitis and healthy controls. We analyzed whether these two polymorphisms are related with the disease characteristics. Methods: One hundred fifty-seven (75 males and 82 females) unrelated patients with ulcerative colitis attending the Departments of Gastroenterology, Nemazi and Faghihi Hospitals, affiliated to Shiraz University of Medical Sciences, Shiraz, Iran were enrolled into this study. Ninety-four age- and sex-matched healthy volunteers with no history of chronic bloody diarrhea and abdominal pain (41 males and 53 females) served as the control group. The change at position -509 (C/T) of the transforming growth factor-betal gene was studied using restriction fragment length polymorphism-polymerase chain reaction in this study. Results: The mean age of patients was 36.4 (range: 23 - 51) years. The genotype at position -509 (C/T) in 58 (37%) patients with ulcerative colitis, and 39 (41.5%) normal subjects, were homozygous as CC. In addition, 65 (41.5%) patients and 44 (47%) normal individuals were heterozygous as CT. Thirty-four (21.5%) of 157 patients, and 11 (11.5%) of 94 normal individuals, were homozygous as TT. There was no statistically significant difference between patients and normal female individuals in respect to genotype distribution and allele frequency at the said position (P = 0.138). Conclusion: No association could be found between transforming growth factor-betal -509 (C/T) promoter gene polymorphism and patients with ulcerative colitis.