We also found microbial carbohydrate metabolism to be altered in Parkinson’s disease which might be a contributor to the insulin impairment observed commonly in Parkinson’s patients [68]; glucagon-like peptide-1 receptor agonists, which act in the gut-brain axis pathway and regulate blood glucose, have shown therapeutic potential in clinical studies of PD [69]. The gene discussed is GLP1R; the disease is Parkinson disease.