Effects of Amerindian Genetic Ancestry on Clinical Variables and Therapy in Patients with Rheumatoid Arthritis.

Objective: To define whether Amerindian genetic ancestry correlates with clinical and therapeutic variables in admixed individuals with rheumatoid arthritis (RA) from Latin America.

Methods: Patients with RA (n = 1347) and healthy controls (n = 1012) from Argentina, Mexico, Chile, and Peru were included. Samples were genotyped for the Immunochip v1 using the Illumina platform.

Rheumatoid arthritis in Latin Americans enriched for Amerindian ancestry is associated with loci in chromosomes 1, 12, and 13, and the HLA class II region.

Objective: To identify susceptibility loci for rheumatoid arthritis (RA) in Latin American individuals with admixed European and Amerindian genetic ancestry.

Methods: Genotyping was performed in 1,475 patients with RA and 1,213 control subjects, using a customized BeadArray containing 196,524 markers covering loci previously associated with various autoimmune diseases. Principal components analysis (EigenSoft package) and Structure software were used to identify outliers and define the population substructure.