Interestingly, four of the five patients (80%) who developed MS prior to hyperthyroidism carried the MS-related DRB1*15:01 allele, whereas only one (11.1%) of the nine patients (eight MS and one NMOSD) who developed hyperthyroidism prior to CNS demyelinating disease carried this allele. The gene discussed is HLA-DRB1; the disease is demyelinating disease of central nervous system.