Scientists uncover genetic link between sleep disorders and neurodevelopmental conditions

A new study has uncovered a biological cause for severe sleep disturbances and hyperarousal in neurodevelopmental disorders. Mis-spliced neuronal microexons trigger a sharp rise in cAMP levels, leaving the brain in a state of permanent overexcitement. This discovery provides a clear link between genetic alterations and conditions like autism and schizophrenia. Researchers found that disrupted alternative splicing of tiny neuronal microexons in zebrafish leads to sensory hypersensitivity, hyperarousal, and insomnia. The genetic change causes a spike in cAMP signalling within the forebrain, resulting in heightened neural activity and daytime hyperactivity.

The study also demonstrated that raising cAMP in normal fish instantly produced hyperactive behaviour. Conversely, introducing a chemical inhibitor to lower cAMP in mutated zebrafish restored normal activity and sleep patterns.

This arousal regulation mechanism appears to be deeply ancient. Identical sleep deprivation patterns in flies and zebrafish suggest the same pathway exists in mammals and humans. The findings confirm that microexon mis-regulation directly underlies the severe sleep and anxiety issues seen in certain neurodevelopmental disorders. The research confirms that cAMP acts as an internal thermostat for neuronal activity. By targeting cAMP levels, scientists could potentially develop treatments for hyperarousal and insomnia linked to genetic mutations. The conserved nature of this pathway across species strengthens its relevance to human conditions.