Depending on the presence or absence of the susceptible alleles for type 1 diabetes, DR3 and DR4, we have grouped the genotypes in 3 categories: 0 risk alleles (no DR3 no DR4 present); 1 risk allele (only one allele DR3 or DR4 is present); 2 risk alleles (individuals homozygous for DR3 or DR4, or DR3-DR4 heterozygous). The gene discussed is TNFRSF10A; the disease is type 1 diabetes mellitus.