Alu elements and post-transcriptional processing of transcripts.

The majority of human genes include Alu repetitive elements in their introns. If these sequences accumulate mutations, they may wrongly signal transcriptional processing events, resulting in alternative splicing of exons or altered polyadenylation, which may affect gene function.

Figure from Deininger Genome Biology 2011 12:236 ; text 2013 by Steven M. Carr