P457 IBD couples and their offspring: a European survey

Abstract Background Small studies have shown that the frequency of inflammatory bowel disease (IBD) is significantly increased after marriage to an individual with the disease relative to what would be expected by chance alone. Furthermore, the offspring of these couples have a significantly increased risk of developing the disease. The aim of this study was to identify couples where both spouses have IBD and their offspring in a larger cohort and to characterise their phenotype. Methods This was a cross-sectional study including couples where both members were affected with IBD and their offspring. An electronic survey in seven languages was distributed by the European Crohn’s and Colitis Organization (ECCO), European Federation of Crohn’s and Ulcerative Colitis Associations (EFCCA) and national patient′s associations from June 2018 to December 2019. Results We identified 51 couples where both members had IBD. There was consanguinity in one couple. There was a representation of couples living in nine different countries. Thirty (59%) couples were concordant for IBD, 14 for Crohn’s disease (CD) and 16 for ulcerative colitis (UC). Within 49 couples, 21 (43%) were diagnosed prior to cohabitation, in 7 (14%) one spouse was diagnosed before and the other after a mean of 7.2 ± 8.9 years after cohabitation, and in 21 (43%) the onset of disease was after cohabitation for both (the first member developed IBD after a mean of 8.3 ± 8.4 years of cohabitation and the second one 4.1 ± 4.5 years after the first). The prevalence of IBD in the 58 children born from these couples was 9%. The cumulative probability of developing disease in the progeny was 3% at 10 years, 11% at 15 years and 15% at 20 years of age. Conclusion This survey identified 51 couples with IBD across Europe; 59% were concordant for IBD type and in 57% the diagnosis of at least one spouse was made after cohabitation. In a wider population, the risk for the progeny was at most 15% at the age of 20, lower than previously reported.