CpG: In genetics, a site where cytosine (C) lies next to guanine (G) in the DNA sequence. (The p indicates that C and G are connected by a phosphodiester bond.) Methylation of DNA occurs at any CpG site. From Healthy Resources How IL Inhibitors Work to Treat PsoriasisModerate to Severe UC: Targeted SolutionsExpert Insight on a New Treatment for C3G Featured Centers What Are the Best PsA Treatments for You?Understanding Biologics 10 Things People With Depression Wish You Knew