Functional polymorphisms in cell death pathway genes FAS and FAS ligand and risk of alopecia areata.

FAS and FAS ligand (FASLG) are important proapoptotic proteins that have a significant function in regulating cell growth and apoptosis and play essential roles in many human autoimmune diseases. Alopecia areata (AA) is hypothesized to be an organ-specific autoimmune disease mediated by T cells to the hair follicles. The concept of an autoimmune mechanism as the basis for AA led us to investigate a possible association between the FAS and FASLG polymorphism with AA susceptibility and disease progression on AA patients in Turkish population. The study group consisted of 118 unrelated patients with AA and 118 unrelated healthy controls. We genotyped FAS-670 A/G and FASLG-124 A/G polymorphisms and assessed their association with AA risk. A statistically significant difference was observed between patients and controls according to genotype frequencies of FAS gene (p = 0.0002). GG genotype of 670 A/G polymorphism was found to be protective against AA (p = 0.000, OR 0.07, 95 % CI 0.00-0.41). It can be concluded there is a reduced risk of AA risk appeared to be associated with FAS-670 A/G. No association was observed between AA patients and controls according to genotype and allele distribution of FASLG gene 124 A/G polymorphism (p = 0.1297, p = 453, respectively). In conclusion, we provide evidence that FAS/FASLG polymorphisms may have an effect on the risk of AA in the Turkish population. These findings provide an additional support to a genetic basis for AA development.