Association between IL17A/IL17RA Gene Polymorphisms and Susceptibility to Alopecia Areata in Korean Population

  • MD Woo-Young Sim, Department of Dermatology, College of Medicine, Kyung Hee University, Korea
  • MD Hwi-Jun Kim, Department of Dermatology, College of Medicine, Kyung Hee University, Korea
  • MD Hee-Ryung Cho, Department of Dermatology, College of Medicine, Kyung Hee University, Korea
  • MD Bark-Lynn Lew, Department of Dermatology, College of Medicine, Kyung Hee University, Korea
  • MD Joo-Ho Chung, Department of Pharmacology, College of Medicine, Kyung Hee University, Korea

Background: Alopecia areata (AA) is marked by autoimmune assault on the hair follicle resulting in hair loss. T helper 17(TH17) cell subset has important roles in protecting the host against extracellular pathogens, but also promotes inflammatory pathology in autoimmune disease, and it expresses both interleukin(IL)-17A and IL-17F, which can signal via the IL-17 receptor A (IL-17RA).
Objective: To investigate the significance of IL17A and IL17RA gene polymorphisms in the susceptibility to AA and understand the pathogenesis of AA.
Methods: We conducted case-control association study of 238 AA patients and 270 matched healthy controls. Genotypes of total two single nucleotide polymorphims (SNPs) in the IL17A gene and four SNPs in the IL17RA genes were studied. The statistical analyses were performed according to onset age, the presence of family history, clinical subtypes of AA, and presence of nail involvement or body hair involvement.
Result: Two SNPs (rs879575 and rs879577) of IL17RA gene showed significant difference between AA patients group and controls group. One SNP (rs2229151) of IL17RA gene showed significant difference between the early onset AA and late onset AA. Two SNP (rs2275913 and rs3819024) of IL17A gene showed significant differences between patchy type of AA and AU or AT and between presence of nail involvement and normal nail appearance. Any SNPs of IL17A or IL17RA were not within a strong LD block.
Conclusion: IL17RA gene polymorphisms may contribute to the increased susceptibility to AA in Korean population, and IL17A or IL17RA gene polymorphisms may be associated with phenotype of AA.