In the same issue of Nature Genetics, their team and collaborators showed that mutations in the human ortholog of the gene, FOXP3, cause the fatal immune dysregulation, polyendocrinopathy, enteropathy, X-linked syndrome (IPEX syndrome), which is marked by intractable diarrhea, type 1 diabetes (T1D), and eczema in young males (3). This evidence concerns the gene FOXP3 and type 1 diabetes mellitus.