Scientists for the first time have edited the DNA of a patient in a bold attempt to cure a genetic disease. On Monday, 44-year-old Brian Madeux from California received billions of copies of a corrective gene and a genetic tool to cut his DNA in a precise spot.

Madeux who has a metabolic disease called the Hunter syndrome said he was humbled to take the test. He added that he was willing to take the risk and hoped that it would help him and other people as well.

 The result of the test would be known only after a month and can be confirmed only after three months. If it is a success, the new technique could give a major boost to the fledgling field of gene therapy. Scientists have edited genes before, but by altering cells in labs and then returning them to patients.

In the new technique, genetic tinkering is happening in a precise way inside the body – like sending a miniature surgeon along to place the new gene in exactly the right location.

Dr Sandy Macrae, president of Sangamo Therapeutics said, “We cut your DNA, open it up, insert a gene, stitch it back up. Invisible mending.It becomes part of your DNA and is there for the rest of your life.”

The success of this therapy will help people who are suffering from incurable metabolic diseases.