In PD, ENT-01 (by Enterin Inc.)reduces alpha-synuclein accumulation in the neurons in the gut, restores enteric neuron functions, and repairs the dysfunctional gut-brain axis in PD, and a clinical trial was completed in 2018 which treated constipation in over 80% patients, and revealed the reversal of a neurodegenerative process in PD patients for their symptoms (156). This evidence concerns the gene SNCA and Parkinson disease.