HLA-DRB1 and optic neuritis: In addition, a significant linkage between HLA-DRB1 * 15:01 and HLA-DQB1 * 06:01 alleles (Pc ≤  0.001 and Pc =  0.012, respectively) were presented among Jordanian MS patients with optic neuritis compared to Jordanian MS patients without optic neuritis.