This document discusses long non-coding RNAs (lncRNAs), which are RNA transcripts longer than 200 nucleotides that do not code for proteins. It provides background on lncRNAs, describing how they are classified and can function as signals, decoys, guides, or scaffolds. The document also examines the roles of lncRNAs in several human diseases like cancer, cardiovascular disease, Alzheimer's, and diabetes. It concludes that lncRNAs play significant roles in disease pathogenesis and could serve as biomarkers or therapeutic targets, and that further research is needed to fully understand lncRNA functions in vivo.