Circular RNAs (circRNAs) are a kind of non-coding RNA molecule with highly stable circular
structures. CircRNAs are primarily composed of exons and/or introns. Recently, a lot of exciting
studies showed that circRNA played an essential role in the development of nervous system diseases.
Here, classification, characteristics, biogenesis, and the association of circRNA dysregulation with nervous
system diseases, such as Alzheimer’s disease, are summarized. The review not only contributes to a
better understanding of circRNAs, but also provides new research directions toward the diagnosis, treatment,
and prevention of nervous system diseases.