Ancestry correlations indicated that the DRB1*16 allele and -DRB107-DQB1*0201 haplotype were protective for T1D, that the DQB1*0501 allele, initially characterized as protective, was neutral, and that the haplotype DRB1*10-DQB1*0501 was protective. The gene discussed is HLA-DRB1; the disease is type 1 diabetes mellitus.