HLA-DRB1 and neuromyelitis optica: Notably, all NMO risk alleles HLA-DRB1*08:02, -DRB1*16:02 and -DRB1*14:06 were inferred to be of Native American ancestry, while risk alleles -DQB1*04:02 and -DQB1*03:01 were predominantly of NAT ancestry both in cases and controls.