Abstract
This study aimed to investigate the genetic polymorphisms of interleukin-23 receptor (IL-23R, IL23R) and endothelial nitric oxide synthetase (eNOS, NOS3) in Saudi cases with alopecia areata (AA). The trial is a case-controlled study conducted on 78 Saudi patients with AA and 93 normal healthy unrelated controls from the same locality. For all participants, characterization of IL23R R381Q (Arg381Gln) and NOS3 E298D (Glu298Asp) gene polymorphisms was carried out using the real-time PCR technique. Saudi cases with AA showed a significantly lower frequency of the protective IL23R 381Q (Gln) allele compared to controls (3.2 vs. 9.5%, P = 0.04). None of the cases (0.0%) were positive for IL23R 381QQ (Gln/Gln) homozygous genotype compared to controls (24%). Cases did not show a significant difference from the controls regarding frequencies of all NOS3 (E298D) polymorphic variants and alleles. Positive family history of AA was found in 22 (28.2%) cases, while parental consanguinity was positive in 21 (26.9%) cases. Subgroups with different clinical criteria showed nonsignificant difference regarding their genotypic variants except for males who showed a higher IL23R RR (Arg/Arg) genotype than females (100 vs. 85.3%, P = 0.01). Susceptibility to AA was associated with a lower frequency of IL23R 381Q allele, but not associated with the NOS3 E298D polymorphic variants.