In performing lean body donor (allogeneic) versus self (autologous) fecal microbiota transplantation in male subjects with metabolic syndrome, Kootte (17) found a significant improvement in insulin sensitivity after 6 weeks of allogenic fecal microbiota transplantation, accompanied by changes in microbiota composition and changes in plasma metabolites, with no cases of adverse effects during this experiment. This evidence concerns the gene INS and metabolic syndrome.