Genotypic interaction and gender specificity of common genetic variants in the p53/mdm2 network in Crohn's disease.

ABSTRACT

BACKGROUND/AIMS: Defective p53-mediated apoptosis and cell cycle control have been implicated in the immunopathogenesis of Crohn's disease (CD). Since common functional variants of p53 (SNP72 G/C) and its key negative regulator mdm2 (SNP309 T/G) have been reported to affect cellular apoptotic and cell cycle arrest capacities, we assessed the effects of these variants on CD susceptibility and their relationship to NOD2/CARD15 as a well-established genetic CD risk factor. METHODS: The variants SNP72 G/C and SNP309 T/G were genotyped in 149 European CD patients and 478 healthy controls. Subgroup analysis was performed in relation to NOD2/CARD15 status and to demographic/clinical characteristics. RESULTS: The p53 SNP72 CC genotype tended to be less frequent in CD. This reached statistical significance only in the male cohort (0 vs. 7.3%; p = 0.037). Genotype and allele frequencies of both single-nucleotide polymorphisms (SNPs) were otherwise not significantly different. In the combined genotypic analysis, the genotype p53 SNP72 CC was significantly underrepresented in mdm2 SNP309 TT homozygotes (0 vs. 9.7%; p = 0.034). No association was observed between NOD2/CARD15 and the respective SNPs. CONCLUSION: We report on a gender-specific protective effect of the low-apoptotic SNP72 CC genotype, and a gender-unrestricted genotypic interaction between SNP309 TT and SNP72 CC, which, for the first time, links sequence variation of the p53/mdm2 network to CD, independent of NOD2/CARD15.