The **TRAF1/C5** locus confers risk for familial and severe alopecia areata
Faculty of Medicine and Health Sciences
Faculty of Pharmaceutical, Biomedical and Veterinary Sciences . Biomedical Sciences
British journal of dermatology. - Oxford
, p. 866-869
University of Antwerp
Background Alopecia areata (AA) is a common hair loss disorder with a complex mode of inheritance. Autoimmune mechanisms are presumed to be crucial aetiologically. It is plausible that a number of autoimmune disorders may share a common genetic background. This phenomenon has been demonstrated in previous studies, which have shown an overlap of susceptibility alleles between AA and other autoimmune disorders. Recent studies have shown that genetic variants on the TRAF1/C5 (tumor necrosis factor receptor-associated factor 1, complement component 5) locus confer susceptibility to rheumatoid arthritis (RA). Objectives To examine the role of the TRAF1/C5 locus in the development of AA using a large sample of 1195 patients with AA and 1280 controls. Methods We genotyped the two most significant single nucleotide polymorphisms (SNPs) (rs10818488, rs2416808) from a former RA candidate gene study. After having obtained evidence for association, we performed a fine-mapping study and genotyped the locus with an additional 27 SNPs. Results While no significant result was obtained for the overall sample, rs2416808 showed significant associations in the analysis of the subgroups with severe AA and with a positive family history. The most significant P-value for rs2416808 was in familial cases (P = 0·004, Pcorr = 0·026). The fine mapping revealed significant associations for four additional SNPs in the analysis of subgroups, with rs2416808 remaining the most significant marker. Conclusions Our results point to the involvement of the TRAF1/C5 locus in the aetiology of familial and severe AA, and provide further support for a shared aetiology between AA and other autoimmune disorders.