PTPN22 and type 1 diabetes mellitus: Furthermore, rs2476601 and rs1893217 SNPs on PTPN22 and PTPN2 genes, respectively, were associated with a lower abundance of beneficial bacteria such as Faecalibacterium, Bilophila, and Coprococcus, in addition to a higher abundance of Bacteroides in many auto-immune diseases such as Crohn’s disease, and since these SNPs are common also in T1D, it may indicate a possible correlation with gut microbiome [192,193].