Of 477 trio families, 301 families carried at least one HLA-DRB5*01:01:01~HLA-DRB1*15:01:01:01 haplotype, and 252 families had one MS-affected child with the HLA-DRB5*01:01:01~HLA-DRB1*15:01:01:01 haplotype. The gene discussed is HLA-DRB1; the disease is myeloid sarcoma.