P902 Native American Mapuche ancestry is related to higher IBD risk in Chileans
Pérez, T.(1,2)*;Bustamante, M.L.(3);Magne, F.(3);Travisany, D.(4);Alvarez-Lobos, M.(1);Hernandez-Rocha, C.(1);Azocar, L.(1);Aguilar, N.(1);Espino, A.(1);Estela, R.(2);Escobar, S.(2);Zazueta, A.(3);Baez, P.(5);Silva, V.(2);Arriagada, E.(2);Barahona, C.(6);Zollner, L.(6);Miquel , J.F.(1);Lorenzo-Bermejo, J.(6);
(1)Pontificia Universidad Católica de Chile, Department of Gastroenterology, Santiago, Chile;(2)Hospital San Borja Arriarán, Department of Gastroenterology, Santiago, Chile;(3)University of Chile, Faculty of Medicine- ICBM, Santiago, Chile;(4)Universidad de la Americas, NIDS- Núcleo de Investigación en Data Science- Facultad de Ingeniería y Negocios, Santiago, Chile;(5)University of Chile, Center for Mathematical Modeling - University of Chile ..., Santiago, Chile;(6)University of Heidelberg, Statistical Genetics Research Group- Institute of Medical Biometry and Informatics, Heidelberg, Germany;
Background
Most genetic association studies rely on Caucasian, African and Asian individuals with inconsistent results depending on the population investigated, suggesting that genetic susceptibility to inflammatory bowel disease (IBD) may depend on interactions between ethnicity and genetic-environmental factors. Aim: To explore the contribution of genetic ancestry to IBD risk in Chileans. Aim: To explore the contribution of genetic ancestry to IBD risk in Chileans.
Methods
192 Chilean IBD patients were genotyped using Illumina’s Global Screening Array. Genotype data was combined with similar information from 3147 population-based Chilean controls from a published study on gallstones, body mass index, c-reactive protein and gallbladder cancer in Chileans (Barahona et al., Hepatology 2021). The individual proportions of Aymara, African, European and Mapuche ancestry were estimated using the software ADMIXTURE (supervised estimation). Using the statistical software R version 4.2.1, we calculated the odds ratios (OR) and 95% confidence intervals (CI) for gender, as well as age and ancestry proportions grouped into quartiles using the library "epitools".
Results
Table 1 shows the investigated characteristics of the study population and their association with IBD risk. For example, the 1st and 3rd quartiles of the proportion of Mapuche ancestry in IBD patients were 24.7% and 34.2%, respectively, and the corresponding OR was 2.30 (95%CI 1.52-3.48) for the lowest versus the highest group.
Conclusion
The type and proportion of Native American ancestry in Chileans seems to be associated with IBD risk.