This analysis suggests that susceptibility T1D alleles within the IL-2/Treg pathway may be associated with a decreased abundance of a number of members of the Clostridiales, Bacteroides, Lachnospiraceae, Ruminococcaceae, and Rikenellaceae families, while only a few OTUs were positively associated with T1D risk. The gene discussed is IL2; the disease is type 1 diabetes mellitus.