[MicroRNAs in bipolar disorder: diagnostic and therapeutic applications]

Bipolar disorder is a severe mental disease of unknown etiology that affects about 1% of the population. It is characterized by mood changes, alternating episodes of mania with depression. The current experimental and epidemiological data suggest that bipolar disorder represents a group of disorders with similar symptoms caused by the combination of genetic and environmental factors. Genetic analysis has identified several genes whose dysfunction might predispose to the disorder, although most of the results have not been confirmed in other studies.

The aim of this review is to analyze the origin of bipolar disorder from a genetic perspective, with emphasis on miRNAs encoding genes. The response of patients to drugs such as lithium and valproate, and a series of data from different experimental approaches show that in some cases of bipolar disorder, genes encoding miRNAs might be involved. These non coding RNAs elements regulate gene expression and could participate in the development of diseases such as cancer, immune system disorders, heart disease and different mental and neurological disorders.

Because the administration of mood stabilizers has been found to modify the expression of some miRNAs, this paper suggests that knowledge of the functions of these regulators could help to diagnose some cases of bipolar disorder identifying molecular markers in plasma. This methodology would also allow applying new strategy founded on effective therapeutic targets for personalized treatment.