New hope on muscular dystrophy

LONDON: A radical treatment for muscle-wasting diseases such as muscular dystrophy has successfully "cured" the condition in laboratory mice affected by the same disorder.

Scientists used a harmless virus to infect all the muscles in the animal's body with a healthy version of a muscle-strengthening gene that the mouse had lacked since birth.

The researchers claim the results are a major breakthrough in the use of gene therapy in treating a range of muscle disorders that result from the inheritance of defective genes.

They believe the first clinical trials for treating muscular dystrophy in humans could begin in a decade.

A major problem in using gene therapy for muscle-wasting diseases has been to find a way of injecting the healthy gene into all affected muscles, particularly those that lie deep inside the body.

A team led by Professor Jeffrey Chamberlain, of the University of Washington in Seattle, has used a virus that seems to be capable of delivering genes to the deepest muscles without causing any apparent harm.

The study, reported in the journal Nature Medicine, found that the muscle cells of the affected mice began to strengthen and the improvement was seen in every muscle sample analysed.

"We have a clear proof of principle that it is possible to deliver new genes body-wide to all the striated [voluntary] muscles of an adult animal," Professor Chamberlain said.

"Finding a delivery method for the whole body has been a major obstacle limiting the development of gene therapy for the muscular dystrophies."

The researchers genetically engineered the virus, called adeno-associated virus, with a healthy copy of a gene that is responsible for the production of a protein called dystrophin, which is lacking in people with muscular dystrophy.

A genetic defect in the production of healthy dystrophin results in Duchenne muscular dystrophy, an inherited condition affecting one in every 3500 newborn boys.

Without the protein, muscles weaken significantly, leading to breathing difficulties and heart problems that usually result in sufferers dying in their 20s or 30s.

Although more work on animals needs to be done before the technique could be applied to humans, Professor Chamberlain believes the virus will be safe to use on people because it cannot replicate on its own, so causing further problems.

- INDEPENDENT