Duchenne muscular dystrophy is the most severe form of muscular dystrophy. It affects about one in every 3500 boys who are born – about 100 boys a year. It is a sex-linked genetic condition which means the boys cannot make a protein called dystrophin, a protein which is vitally important for maintaining healthy muscles. Without it the muscles weaken and waste away, so that by their early teens most affected boys are confined to a wheelchair and their life expectancy is only 20-30 years.

The faulty gene causing this condition is very large, which makes normal gene therapy techniques difficult. However, researchers in the United States and in Britain have found ways of using parts of a healthy gene, called mini-genes, to repair the damaged DNA, enabling the muscles to produce dystrophin and to function in a much more normal way. What is more, the effect has been long term – the protein was still being made a year after the gene was inserted. The only problem is that the gene therapy technique has so far only been tried in mice.

But the results from a group of scientists at the Hammersmith Hospital in London are so encouraging that there are hopes it will not be long before the technique can be tried in human volunteers. The problem is that gene therapy has not yet been fully successful in overcoming any genetic diseases, so it will be brave patients – and their parents – who undergo the first trials of this new treatment which could, just possibly, completely change their lives.