SNCA and Parkinson disease: Enteric neurons in the aged murine and human colon were found expressing risk genes for Hirschsprung’s disease (RET, PHOX2B, GFRA1, and ECE1), autism spectrum disorders (NRXN1, ANK2, DSCAM, and GABRB3), inflammatory bowel disease (BTBD8, GRP, CNTNAP2, etc.), and PD (DLG2, SNCA, Lrrk2, Park2, etc.), suggesting ENS contribution to these diseases [9,10,119].