LRRK2 and inflammatory bowel disease: Nonetheless, traits that currently have been confirmed as susceptibility genes for IBD and are subject of intense research efforts include NOD2 [20], HLA class II [24], IL23R [14], and genes involved in autophagy (e.g., Leucine-rich repeat kinase 2 [LRRK2] [25], ATG16L1 [16], and immunity related guanosine triphosphate M [IRGM]) [17].