A gene involved in brain development that can lead to severe disability and infant death has been identified by scientists.

Mutations in the gene cause profound developmental problems and seizures in young children, researchers have found.

Experts believe the "significant" insight could help them to uncover new drugs and may also shed light on conditions such as Alzheimer's disease.

The team of scientists and doctors, led by the University of Edinburgh, worked with children with a range of severe problems, including seizures and abnormal brain scans and discovered that the infants all had mutations in a gene known as PLAA.

Researchers have named the rare condition PLAA-associated neurodevelopment disorder, or PLAAND.

Using a mouse with the same mutation, the team demonstrated how this gene has to function properly for a healthy brain to develop.

They found that PLAA is essential for signalling cells to clear away a build-up of damaged proteins, which is crucial for brain cell function.

Cells in children with PLAAND have lost this ability, meaning that damaged proteins build up.

This then causes severe problems in brain development and at synapses, the parts of of brain cells that communicate with other cells.

Scientists believe the results of the study could help them uncover new drugs to treat PLAAND and could further understanding of Alzheimer's disease, in which there is also an issue with damaged protein build-up.

Dr Pleasantine Mill, of the university's MRC (Medical Research Council) Human Genetics Unit, said: "Pinpointing mutations in this gene that lead to such severe outcomes in the affected children is an important advance.

"Children affected with PLAAND die before the age of six and most heart-breaking for their families is that they fail to meet any developmental milestones.

"There is no treatment currently available. In identifying this gene and the processes it controls, we have made significant steps in understanding its role in healthy brain development, which will help us target drug studies in future."

The study, published in American Journal of Human Genetics, was funded by the MRC.