The evaluation of IL-4 VNTR intron 3 and TNF-α (rs1799964) gene polymorphisms in Egyptian patients with alopecia areata: a case–control study

Abstract

Alopecia areata (AA) is a non-scarring hair loss condition that usually affects the scalp. The exact pathogenesis is poorly understood; however, multiple factors like genetics, environmental, psychological, and immunological factors may have a role. The purpose of this study was to look into possible links between the functional interleukin-4 (IL-4) gene intron 3 variable number of tandem repeats (VNTR) and TNF-(rs1799964) gene polymorphism and AA susceptibility. This case–control study consisted of 79 unrelated patients and 156 age- and sex-matched healthy individuals as a control group. The Severity of Alopecia Tool was used to assess the extent of hair loss from the scalp. Polymerase chain reaction (PCR) with specific primers was used to determine IL-4 gene 70-bp VNTR polymorphism while polymerase chain reaction-restriction fragment length polymorphism (PCR–RFLP) was used to investigate TNF-α (rs1799964) gene polymorphism. None of the selected polymorphisms for both genotypes and alleles had statistical significance when patients and controls were compared with each other (p-values for IL-4 VNTR were 0.11, 0.74, 0.052 and 0.27 and for TNF-α polymorphism was 0.71, 0.43, 0.65 and 0.55, respectively, for codominant, dominant, recessive and overdominant models of inheritance, respectively). Furthermore, the same results were retrieved when the genotypes were compared with the patient’s clinical and demographic data (p-value > 0.05). The findings indicate that IL-4 VNTR intron 3 and TNF-α (rs1799964) gene polymorphisms are not linked to the development of AA in the Egyptian population.