In conclusion, we found that three variants (rs2066808, rs2371494, rs11575248) in the IL-23A gene and one variant (rs1884444) in the IL-23R gene were associated with the risk of MS and other IDD, and the serum levels of IL-23A in the MS patients were also altered by the variants, providing new evidence for the importance of IL-23A and IL-23R in the pathogenesis of the MS disease and demonstrating the differences between MS and other demyelinating syndromes in pathogenesis. Here, IL23R is linked to myeloid sarcoma.