ABSTRACT
Previous studies have demonstrated that in admixed populations, West African ancestry is associated with an increased prevalence of systemic lupus erythematosus (SLE). In the current study, the effect of Amerindian ancestry in SLE was examined in an admixed population in Argentina. The Argentine population is predominantly European with approximately 20% Amerindian admixture, and a very small (<2%) contribution from West Africa. The results indicate that Amerindian admixture in this population is associated with a substantial increase in SLE susceptibility risk (Odds Ratio=7.94, P=0.00006). This difference was not due to known demographic factors, including site of collection, age and gender. In addition, there were trends towards significance for Amerindian ancestry influencing renal disease, age of onset and anti-SSA antibodies. These studies suggest that populations with Amerindian admixture, like those with West African admixture, should be considered in future studies to identify additional allelic variants that predispose to SLE.
Subject(s)
Genetic Predisposition to Disease , Indians, South American/genetics , Lupus Erythematosus, Systemic/genetics , Algorithms , Argentina/epidemiology , Bayes Theorem , Case-Control Studies , Computational Biology/methods , Genetics, Population , Genotype , Geography , Haplotypes , Humans , Logistic Models , Odds Ratio , Polymorphism, Single Nucleotide , Risk FactorsABSTRACT
PDCD1, an immunoreceptor involved in peripheral tolerance has previously been shown to be genetically associated with systemic lupus erythematosus (SLE). PDCD1 has two ligands whose genes are located in close proximity on chromosome 9p24. Our attention was drawn to these ligands after finding suggestive linkage to a marker (gata62f03, Z=2.27) located close to their genes in a genome scan of Icelandic families multiplex for SLE. Here, we analyse Swedish trios (N=149) for 23 single nucleotide polymorphisms (SNPs) within the genes of the PDCD1 ligands. Initially, indication of association to eight SNPs was observed, and these SNPs were therefore also analysed in Mexican trios (N=90), as well as independent sets of patients and controls from Sweden (152 patients, 448 controls) and Argentina (288 patients, 288 controls). We do not find support for genetic association to SLE. This is the first genetic study of SLE and the PDCD1 ligands and the lack of association in several cohorts implies that these genes are not major risk factors for SLE.
