Genetic Association between Interleukin Genes and Alopecia Areata in Jordanian Patients

Alopecia areata (AA) is a multifactorial autoimmune disease with a strong genetic predisposition. A variety of genes involved in immunity and inflammatory responses, such as cytokines, are suspected to increase the risk of developing AA. In which, different interleukin (IL) genes that associated with several autoimmune diseases and AA in varied populations. The objective of this study was to investigate the possible genetic association of AA with ten variants of single nucleotide polymorphism (SNP) in IL12B,IL13,IL16,IL17A, and IL18 genes among Jordanian patients.

In this case-control study, peripheral blood samples of 152 Jordanian AA patients and 150 controls (total of 302 subjects) were collected, genomic DNA extracted and genotyped, based on which their allele and genotype frequencies were assessed.

In the rs11073001 SNP located in the exon region of the IL16 gene, the A allele was distributed more frequently in AA patients (p =0.01). A difference was found between the patients and the controls for the rs17875491 SNP in the promoter region of the IL16 gene (p =0.04). The mean age of onset was 27.3±12.6 with male predominance. Most patients (68.4%) were asymptomatic but some reported experiencing associated sensations before the hair loss episodes. The patchy patterns of alopecia were the most common (90.3%). Nail changes were found in 7.3% of the patients.

The findings support the hypothesis of the involvement of IL16 gene in the etiology of AA. Moreover, it emphasizes the variations in the genetic component of AA, as well as the clinical phenotypes among different ethnic groups.