Session Information
Session Type: Abstract Submissions (ACR)
Background/Purpose
Polyautoimmunity [i.e., the presence of two or more autoimmune diseases (ADs) in a single patient] is a frequent phenomenon in autoimmunity, ranging from 10% to 40%. Since polyautoimmunity is most frequently observed in Latin Americans than in Europeans and the diverse population of Latin America and the Caribbean is a powerful resource for elucidating the genetic basis of complex traits due to its high admixture, we aimed to study the effect of ancestry on polyautoimmunity in a Latin American population.
Methods
A total of 508 subjects were examined [240 cases with a single AD, 87 with polyautoimmunity, of whom 36 presented with multiple autoimmune syndromes (MAS, i.e., 3 or more ADs), and 181 matched-controls with no AD]. Genotyping of 32 ancestry informative markers was performed. The individual admixture profile was built in STRUCTURE 2.3.4 by using data of people from known ethnic groups: African (n=148), European (n=160) and Native American (n=278). Different models were calculated varying the number of ancestral populations. The estimated logarithm P(X|K) and the mean value of the log-likelihood were used to choose the most parsimonious model. Ancestry differences between cases (AD, polyautoimmunity and MAS) and controls were assessed by a MANOVA model on ARL transformed ancestral profiles, and fitted in R software 3.0.2.
Results
A high European profile (50%) followed by a similar contribution of the remaining ancestral populations (African 26%, Amerindian 24%) was observed in the studied population. Significant differences of ancestry profiles among the four groups analyzed were detected (Pillai test, p-value: 0.001). The MAS group carried a higher Amerindian composition than the other three groups (p-value: 0.01) along with a lesser European ancestry (p-value: 0.003).
Conclusion
The Amerindian ancestry component affect the development of polyautoimmunity. These results increase the understanding of genetics of autoimmunity and may contribute to design strategies to characterize patients at risk of polyautoimmunity.
Disclosure:
N. Molano-González,
None;
J. Castiblanco,
None;
R. D. Mantilla,
None;
A. Rojas-Villarraga,
None;
J. M. Anaya,
None.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/amerindian-ancestry-influences-polyautoimmunity/