On the other hand, C allele and CC genotype of C1236T and C3435T, as well as G allele and GG genotype of G2677T/A were more frequent in healthy subjects, implying protective role of these variants in UC.
Heterozygous carriers for the variants C1236T, rs2235046 (an SNP in intron 16), and G2677T/A showed a lower risk of developing ulcerative colitis (C1236T: odds ratio [OR] = 0.63, 95% confidence interval [CI] = 0.42-0.93, P = 0.03; G2677T/A: OR = 0.59, CI = 0.39-0.89, P = 0.02; and rs2235046: OR = 0.59, 95% CI = 0.38-0.91, P = 0.009) as compared with homozygotes.
The distribution of the different genotypes of single nucleotide polymorphisms (SNP) G2677T/A and C3435T of MDR1 exons 21 and 26, respectively, was studied in 154 patients (mean age, 44 yr) who had received CsA to treat severe attacks of steroid resistant UC in 11 centers in France and Belgium.
No significant association between G2677T/A polymorphism and any specific subphenotypes was found, nor was there any association with subphenotypic categories of UC and both single nucleotide polymorphisms.
The polymorphism Ala893Ser/Thr (G2677T/A) previously showed significant association with Crohn's disease (CD) and the Ile1145Ile (C3435T) with ulcerative colitis (UC).
Two polymorphisms (C3435T and G2677T/A) of the multidrug resistance 1 gene have been correlated with the altered P-glycoprotein expression and function in humans, and associated with predisposition to ulcerative colitis and Crohn's disease.
This was a case-control analysis of MDR1 C3435T and G2677T SNPs in a large well-characterized Scottish white cohort (335 with ulcerative colitis [UC], 268 with Crohn's disease [CD], and 370 healthy controls).