A cross-sectional survey of multi-generation inflammatory bowel disease consanguinity and its relationship with disease onset

BACKGROUND\AIM: Consanguinity influences the phenotypic variations of some hereditary and immune-mediated disorders, including inflammatory bowel disease. This study estimated the prevalence of consanguinity among the ancestors of patients with inflammatory bowel disease and examined the effect of various consanguinity levels on inflammatory bowel disease onset. PATIENTS AND METHODS: Patients with inflammatory bowel disease who were seen at two gastroenterology outpatient clinics were consecutively recruited and surveyed for demographics, disease onset, and presence of ancestral consanguinity within three generations. The prevalence of different consanguinity levels was calculated. The association between age at inflammatory bowel disease onset and consanguinity was examined. RESULTS: Two hundred seventeen patients were recruited. The mean age, mean age at diagnosis, and mean illness duration were 32.9 ± 13.4, 18.6 ± 11.5, and 8.6 ± 7.7 years, respectively. Of the cohort, 53.5% were women, and 74.2% were native Saudis. Cigarette smoking was reported in 17.1%; 51% had Crohn's disease, while the remaining patients had ulcerative colitis. A family history of inflammatory bowel disease was reported in 29.5% of patients; consanguinity within three generations was reported in 57.6%. Consanguinity in more than one generation was reported in 38.7%; 17.5% had consanguinity in three consecutive generations. There was no association between inflammatory bowel disease onset and multi-generation consanguinity, but there was an association with disease subtype in favor of ulcerative colitis (b coefficient = 7.1 [95% confidence interval = 4.1, 10]). CONCLUSIONS: Consanguinity is extremely common among Saudi patients with inflammatory bowel disease but does not seem to influence age at disease onset. Genetic studies are needed to further clarify the effect of consanguinity on disease behavior.