The gene could bring treatments closer
Scientists may have found a genetic mutation which may help unravel why people get the devastating condition motor neurone disease (MND).
While experts know that some cases of motor neurone are hereditary, they are hopeful that their finding could offer some explanation to thousands more patients.
However, a new treatment or a cure for the condition is still a long way off, they concede.
This will doubtless accelerate our search for a cure
Dr Brian Dickie, Motor Neurone Disease Association
There are approximately 5,000 Motor Neurone Disease patients in the UK.
The illness appears often in middle age and the symptoms involve a progressively spreading muscle weakness.
While there is a treatment that can slow this process in some patients, there is no cure and the disease is always fatal.
Researchers from University College London, Queen Mary's School of Medicine and Dentistry, Munich Technical University and the German National Research Centre for Environment and Health looked at genetic mutations in mice.
They identified a gene, which, when mutated, produced mice which developed a motor neurone -like condition.
This gene, called the dynein gene, appears to be involved in the transport of substances within neurones - the long cells which transmit nerve impulses from the brain to the muscles.
A problem with this dynein "transporter molecule" offers a clear explanation for the previously unexplained death of these cells.
Neurones are the longest cells in the body - they can reach as much as a metre in length - and a deficiency in the ability to transport vital substances from one end to the other could affect this nature of cell far more severely than other cells which might also rely on dynein.
The "mild" mutation in the mice also created an effect similar to the rate of decline in humans, adding weight to the theory that a gene mutation carried since birth could take decades to start causing symptoms of MND.
Studies which examine cells from human patients for signs of an equivalent genetic mutation are now being organised.
Professor Elizabeth Fisher, from University College London, said: "The pathogenetic link between specific gene mutations and selective, progressive degeneration of motor neurones has been the fundamental question in MND research."
Professor Joanne Martin, professor of neuropathology at Barts and the London, said: "We are delighted that this research has helped open new approaches in the study of motor neurone disease.
"It is the culmination of many years of work with national and international colleagues, and marks a significant development in the search for treatments."
Dr Brian Dickie, head of research at the Motor Neurone Disease Association, which funded part of the research, said: "In the vast majority of cases the causes of MND remain unknown.
"This opens up a promising new avenue of research into definitive causes of MND and will doubtless accelerate our search for a cure."