PTPN2 Gene Variants Are Associated with Susceptibility to Both Crohn’s Disease and Ulcerative Colitis Supporting a Common Genetic Disease Background

Background: Genome-wide association studies identified PTPN2 (protein tyrosine phosphatase, non-receptor type 2) as susceptibility gene for inflammatory bowel diseases (IBD). However, the exact role of PTPN2 in Crohn’s disease (CD) and ulcerative colitis (UC) and its phenotypic effect are unclear. We therefore performed a detailed genotype-phenotype and epistasis analysis of PTPN2 gene variants. Methodology/Principal Findings: Genomic DNA from 2131 individuals of Caucasian origin (905 patients with CD, 318 patients with UC, and 908 healthy, unrelated controls) was analyzed for two SNPs in the PTPN2 region (rs2542151, rs7234029) for which associations with IBD were found in previous studies in other cohorts. Our analysis revealed a significant association of PTPN2 SNP rs2542151 with both susceptibility to CD (p = 1.9561025; OR 1.49 [1.34–1.79]) and UC (p = 3.8761022, OR 1.31 [1.02–1.68]). Moreover, PTPN2 SNP rs7234029 demonstrated a significant association with susceptibility to CD (p = 1.3061023; OR 1.35 [1.13–1.62]) and a trend towards association with UC (p = 7.5361022; OR 1.26 [0.98–1.62]). Genotype-phenotype analysis revealed an association of PTPN2 SNP rs7234029 with a stricturing diseas