Polymorphism of FAS and FAS Ligand Genes in Alopecia Areata: A Case-control Study in Egyptian Population

Alopecia areata (AA) is a common dermatologic disease with suspected autoimmune etiology. Tumor necrosis factor superfamily member 6 or CD95 (FAS) and FAS ligand (FASL) are proapoptotic proteins. The relationship between apoptosis and autoimmunity is well recognized. Inflammatory T cells in AA are cytotoxic and possess FAS/FASL antigens.

This study aims to investigate the association between FAS-670 A/G and FASL-124 A/G gene polymorphisms and AA to clarify if these polymorphisms influence disease occurrence or increase disease risk.

A case-control study was conducted on sixty patients with AA, and 40 age- and sex-matched healthy subjects, as a control group. Disease severity was assessed by severity of alopecia tool (SALT) Score. FAS 670A/G and FASL 124A/G gene polymorphisms were investigated by the restriction fragment length polymorphism polymerase chain reaction.

For FAS gene, G/G genotype was significantly higher in cases than in control group with odds ratio 5.1. G allele was more prevalent among patient group with odds ratio 1.75. For FASL gene, A/G genotype was significantly higher in cases than in control group with odds ratio 4.53. G allele was more prevalent among patient group with odds ratio 1.88. GG genotype of FAS was significantly associated with longer disease duration (P =0.001), recurrent attacks (P =0.01), higher SALT score (P =0.009), alopecia universalis (P =0.002), and severe disease (P =0.006).

FAS and FASL gene polymorphisms are associated with AA. Further large-scale studies on different ethnicities are required for more clarification of their role in disease development. Therapeutic modalities based on their inhibition could be promising in the treatment of a common disease like AA.