Hyperactivity symptoms similar to those of Attention-Deficit Hyperactivity Disorder are caused by a mutation in a gene that is involved in the functioning of the brain's nervous system, scientists at Trinity College have discovered.

The finding was made by researchers working with mice.

They found a mutation in a single mouse gene, Elfn1, has a significant behavioural effect.

The team experimentally removed the gene from some mice and compared the effects against those seen in mice with the normal gene.

Although the structure of the brain remained the same and neural connection patterns remained normal, the scientists observed clear evidence of disturbance in brain function in mice lacking the gene.

Evidence included some seizures, which increased in frequency over time, and hyperactivity, which showed an unusual response to the stimulant amphetamine.

The findings are published in the academic journal PLOS ONE.

The results will give scientists a reason to carry out further research to see whether mutations in Elfn1 in humans can give rise to similar symptoms and whether they might play a part in some patients with epilepsy and ADHD.

The study was led by Associate Professor in Genetics at Trinity Kevin Mitchell and Research Technical Officer Dr Jackie Dolan.

In a statement, Professor Mitchell said, "We are at the beginning of this process of figuring out how this gene works and understanding the consequences when it is mutated.

"But, these animals provide a unique model to investigate how subtle changes in brain development can ultimately result in aberrant brain function."