Patient's genes are 'edited' to alter DNA
Doctors have edited a patient's genes in a world-first attempt to alter DNA from within the human body.
The doctors in California administered the experimental intravenous treatment, which provides the body with instructions to change DNA, on Brian Madeux, who suffers from Hunter's syndrome.
People with Hunter's syndrome are unable to break down long, sugary molecules called mucopolysaccharides. This leads to the molecules building up and causing brain and organ damage, and in severe cases it can be fatal.
Sufferers require regular enzyme replacement therapy, but Mr Madeux said he opted to take part in a trial as he was "in pain every second of the day".
The 44-year-old, from Arizona, underwent the treatment at UCSF Benioff Children's Hospital, in Oakland, on Monday.
It is too soon to know whether the pioneering procedure has worked, but if successful his DNA will have the instructions for making the enzyme.
Mr Madeux intravenously received billions of copies of a corrective gene and genetic tools to cut his DNA in a precise spot. They travel to the liver, where cells use the instructions to make molecular scissors and prepare the corrective gene. The DNA is cut, allowing the new gene to slip in. The new gene then directs the cell to make the enzyme the patient lacked.
"We cut your DNA, open it up, insert a gene, stitch it back up. Invisible mending," said Dr Sandy Macrae, president of Sangamo Therapeutics, the Californian company testing this for two metabolic diseases and haemophilia.