The Environmental Determinants of Diabetes in the Young (TEDDY) study has revealed non-HLA genetic factors that contribute to the development of type 1 diabetes mellitus (T1DM). The researchers genotyped 5,164 children for 41 non-HLA single nucleotide polymorphisms (SNPs) known to be associated with T1DM. The initial analysis found that eight of these SNPs were associated with the development of islet autoantibodies in the TEDDY participants, which decreased to four SNPs after adjustment. The team suggest that although genes in the HLA region are risk factors for T1DM, genetic factors in the non-HLA region also contribute to the pathogenesis and progression of T1DM.