Toll-like receptor activation intitially recruits the myeloid differentiation primary response gene (88) (MyD88) protein. A polymorphism *1244 A>G (rs7744) in the 3′-untranslated region of MyD88 has been identified. In the present study, the association of this polymorphism with ulcerative colitis (UC) was investigated. The population studied comprised 922 individuals, including patients with UC (UC cases) and without (controls). Genotyping of rs7744 was performed by PCR single-strand conformation polymorphism and the rs7744 G allele frequencies in the controls and UC cases were 32.8 and 43.5%, respectively (P<0.0001). The results showed that the genotype frequency of the AA homozygote was significantly lower and that of the GG homozygote was significantly higher in the UC cases compared with those in the controls (P=0.0012 for both groups). The rs7744 minor allele variants were significantly associated with susceptibility to UC as indicated by dominant and recessive genetic models. The minor allele variants were associated with an increased risk for UC in the male individuals but not the female individuals. The rs7744 was also associated with a non-continuous phenotype of UC and steroid unused/independent UC. This minor allele homozygote was associated with the disease severity of UC, hospitalization and response to steroid treatment. The results of the present study provided evidence that MyD88 polymorphism rs7744 was significantly associated with the development of UC and that this polymorphism may be associated with the response to treatment therapies for UC.
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