PIK3R4 and inflammatory bowel disease: Specifically, immunity-related genes, such as JAK1, IL6ST, STAT2, and IFNAR1, were more prominent in the IBD-specific analysis, whereas LRRK2 and other phagosome-related genes including PIK3C3, PIKFYVE, PIK3R4, and VAC14 were more significant in the PD-specific analysis (Additional file 1: Fig. S6, Additional file 2: Tables S14 and S15).