For the first time, scientists have found a way to make a miniaturized version of the Duchenne muscular dystrophy gene, increasing the chance that doctors may one day be able to treat the inherited muscle disorder with gene therapy, a method for introducing repair genes into diseased cells.

Researchers at Baylor College of Medicine in Houston have inserted the miniature gene inside muscle cells growing in the laboratory.

The gene directs the production of a protein that has the same size and weight as the normal muscular dystrophy protein, called dystrophin, the lack of which leads to the disease.

When the muscular dystrophy gene was first discovered five years ago, physicians were skeptical that gene therapy for the disease that affects 20,000 American boys was possible because of the size and complexity of the gene.

"The entire gene is 2.5 million base pairs {genetic subunits} long, but most of it is junk DNA," said Baylor's Cheng Chi Lee, lead author of the report that appeared in last week's issue of Nature. The Baylor team squeezed out the extraneous material, leaving a functional gene that was considerably smaller and more manageable.

During the next year, Lee said his team plans to use the gene to reverse muscular dystropy in mice. After that, they hope to begin testing it in people.