Association of NCF2, IKZF1, IRF8, IFIH1, and TYK2 with systemic lupus erythematosus

Abstract

Systemic lupus erythematosus (SLE) is a complex trait characterised by the production of a range of auto-antibodies and a diverse set of clinical phenotypes. Currently, ~8% of the genetic contribution to SLE in Europeans is known, following publication of several moderate-sized genome-wide (GW) association studies, which identified loci with a strong effect (OR&1.3). In order to identify additional genes contributing to SLE susceptibility, we conducted a replication study in a UK dataset (870 cases, 5,551 controls) of 23 variants that showed moderate-risk for lupus in previous studies. Association analysis in the UK dataset and subsequent meta-analysis with the published data identified five SLE susceptibility genes reaching genome-wide levels of significance (P comb<5×10 -8): NCF2 (P comb = 2.87×10 -11), IKZF1 (P comb = 2.33×10 -9), IRF8 (P comb = 1.24×10 -8), IFIH1 (P comb = 1.63×10 -8), and TYK2 (P comb = 3.88×10 -8). Each of the five new loci identified here can be mapped into interferon signalling pathways, which are known to play a key role in the pathogenesis of SLE. These results increase the number of established susceptibility genes for lupus to ~30 and validate the importance of using large datasets to confirm associations of loci which moderately increase the risk for disease. © 2011 Cunninghame Graham et al.