The ends of linear eukaryotic chromosomes are transcribed into different species 
of non-coding transcripts (the telomeric transcriptome), including TERRA 
(telomeric repeat-containing RNA) molecules; however, the functions associated 
with the telomeric transcriptome remain elusive. Experimental evidence 
accumulated during the past few years indicates that the transcriptional 
activity of telomeres is changed in cells in which the integrity of the 
telomeres or the heterochromatic state of chromosome ends is altered. On the 
contrary transcription of a telomere appears not to be influenced by its length. 
In this paper we briefly review the current state of knowledge on the 
composition, biogenesis, and regulation of the telomeric transcriptome from 
yeasts to humans. We also suggest a model in which TERRA is part of the DNA 
damage response triggered by dysfunctional telomeres and discuss the potential 
involvement of telomere transcription in the development of human pathologies.