from Laboratory News by Jose Ramon Bilbao and Ainara Castellanos-Rubio –
As evidence pointing to the importance of non-coding regions of the genome mounts, a team from Spain discover a long non-coding RNA which plays a pivotal role in coeliac disease
Coeliac disease (CD) is an immune-mediated enteropathy caused by ingested gluten that develops in genetically susceptible individuals. Nowadays, it is estimated that around 1% of the European population suffers from this disease. The main genetic factor – contributing 40% of the genetic susceptibility – maps to the HLA (human leukocyte antigen) region. However, HLA variants (DQ2 and DQ8) are not sufficient to develop coeliac disease. As with other complex diseases, in which more than one gene is implicated, the combination of many common variants together with environmental factors will make some of us prone to develop coeliac disease.
The completion of the human genome project has given us new tools to find variants that contribute to the development of common diseases like CD. One of those tools is the Genome Wide Association Studies (GWAS) that look for markers across the genome in order to find genetic variations associated with a particular disease. Around 80% of the phenotype-related loci identified by GWAS of many human diseases map to non-coding regions of the genome, so explaining why the implication of these variants in disease development has been challenging.
In the last few years a new group of RNAs, named long non-coding RNAs (lncRNAs) have been shown to be differentially expressed in several diseases and are gaining importance as functional players in their development. LncRNAs have been implicated in several aspects of cell function, including the control of DNA transcription or the response to stress, and are emerging as an important regulation layer in cell signalling. Interestingly, the link between the GWAS phenotype-related loci on lncRNA expression or function, and its implications for disease, remain uncharacterised, and open a new field of study around the functionality of GWAS hits in intergenic regions.