Like protein-coding genes, all of these ncRNA genes vary in sequence between people, variations which could contribute to complex nervous system disorders. Indeed, ncRNAs have already been implicated in glioma, PraderWilli syndrome, spinocerebellar ataxia, polyglutamine expansion diseases, neurodegenerative disorders and Fragile X syndrome (Mehler & Mattick, 2007). Tourette’s syndrome provides an interesting example because it involves an association between the disorder and polymorphisms, not in a ncRNA, but in a site in the SLITRK1 gene where a microRNA binds to regulate translation (Abelson, Kwan, O’Roak, Baek, Stillman et al., 2005). This opens up the possibility that there will be many more cases where a single polymorphism could create or destroy a ncRNA binding site, altering the regulation of the associated gene. Recent studies have suggested that this is likely to be the case (Saunders, Liang, & Li, 2007).
