FCN2 and systemic lupus erythematosus: In contrast, no association was found between the FCN2 and FCN3 genes with the development of rheumatoid arthritis, even though variants in the FNC2 promoter have been associated with the presence of lupus nephritis in pediatric patients with systemic lupus erythematosus, such is the case of the rs3124952 variant (genotype GG = OR: 2.6; 95% CI: 1.4-4.78; p value = 0.006) and rs17514136 (AA genotype = OR: 3.12; 95% CI: 1.25-7.84; p value = 0.024).