HLA-DRB1 and neuromyelitis optica: However, in Latin American populations, with a high admixed genetic background, DRB1*03 allelic group was associated with NMO in Afro Caribbean26 (NMO-26.2% vs controls-13%, pcB = 0.045), in Mulattoes from Ribeirão Preto25 (NMO—24.1% vs controls 8.9%, pcF = 0.0401), and in Mestizos of Mexico34 (NMO vs 14% vs controls 5%, p = 0.03).