RNA gains a new function: a mediator of neurodegeneration.

Over the past couple of years, it has become evident that some males carrying the fragile X mental retardation (FMR1) premutation, typically viewed to be normal, in fact manifest a neurodegenerative disease with ataxia and tremor. FMR1 premutation alleles uniquely produce FMR1 transcripts with an elongated CGG repeat, leading to the hypothesis that premutant transcripts cause the neurodegenerative disease in carriers. Recently Jin et al. demonstrated, in Drosophila, that FMR1 premutation RNA causes neurodegeneration. These data show RNA can induce neurodegeneration and provide strong evidence that FMR1 RNA mediates the neurodegeneration in human premutation carriers.