Functional polymorphisms of the FAS/FASLG genes are associated with risk of alopecia areata in a Chinese population: a case–control analysis

Background The Fas/Fas ligand system plays a key role in regulating cell growth and apoptosis. Previous findings have suggested that FAS and FASLG polymorphisms are associated with systemic lupus erythematosus, autoimmune hepatitis, vitiligo and other autoimmune‐related disorders. However, to the best of our knowledge, there is no reported study on the associations between FAS and FASLG polymorphisms and the risk of alopecia areata. Objectives To investigate the associations between FAS and FASLG polymorphisms and the risk of alopecia areata in a Chinese Han population. Methods In a hospital‐based case–control study of 84 patients with alopecia areata and 84 controls, we genotyped FAS 1377G>A, FAS 670A>G and FASLG 844T>C polymorphisms and assessed their association with alopecia areata risk. Results We found that a reduced risk of alopecia areata appeared to be associated with the FAS 670AG genotype adjusted odds ratio (OR) 0·43; 95% confidence interval (CI) 0·22–0·86] when compared with the FAS 670AA genotype, but no risk was associated with any of the FAS 1377G>A and FASLG 844T>C genotypes. In the combined analysis, we found that the presence in individuals of two at‐risk alleles of the three FAS/FASLG polymorphisms was associated with a lower risk of alopecia areata (adjusted OR 0·21; 95% CI 0·05–0·89) when compared with the presence of six at‐risk alleles. Conclusions These results suggest that genetic variants in the FAS and FASLG genes may contribute to the aetiology of alopecia areata.