A221 CROHN’S DISEASE POLYGENIC RISK SCORE IS ASSOCIATED WITH FECAL CALPROTECTIN CONCENTRATION IN ASYMPTOMATIC FIRST-DEGREE RELATIVES OF CROHN’S DISEASE PATIENTS

Abstract Background Fecal calprotectin concentration (FC), a measure of gut inflammation is reported to be significantly higher in healthy first-degree relatives (FDR) of Crohn’s disease (CD) patients compared to healthy controls. In contrast, FC in spouses of CD patients was not significantly different from controls, suggesting that a genetic predisposition rather than a shared environmental factor affects FC. Aims We investigated the genetic association with FC in healthy FDRs of CD patients. Notably, these subjects are known to be enriched with CD risk alleles. Methods We investigated 1455 healthy Caucasian FDRs of CD patients from the GEM Project. Subjects were genotyped by HumanCoreEXOME chip and ImmunoChip platforms and then imputed by the Haplotype Reference Consortium v1.1 panel (Michigan Imputation Server). SNPs with a minor allele frequency100). We estimated the heritability of FC to be 27% (27.1%, standard error=9%, p