Differences in genetic architecture between early- and adult-onset inflammatory bowel diseases in the Polish population revealed through genome-wide association and whole exome sequencing studies

Most inflammatory bowel diseases (IBDs), including Crohn’s disease (CD) and ulcerative colitis (UC) are classic polygenic disorders represented by common alleles. While only minority adult-onset IBDs and unknown fraction of early onset IBDs are monogenic disorders with IBD-like presentation, multiple determinants of the very early-onset IBD, characterized by more extensive disease course, remain largely unknown. To define genetic architecture of IBDs in the Polish population, was analyzed simultaneously pediatric and adult cohorts using genome-wide association studies (GWAS) and whole exome sequencing (WES) procedure. To further search for potential differences in genetic architecture of very early- and adult-onset IBD, we performed the whole exome sequencing (WES) analysis on 23 and 21 children diagnosed with CD and UC, respectively, at or before 5 years of age and on 23 and 22 patients diagnosed with CD and UC, respectively, after 40 years. In addition, we WES was conducted on 18 healthy individuals.