World's first gene editing experimented in human body

New Delhi: In a first, scientists from the United States have tried gene-editing on cells inside a patient in California.

44-year-old Brian Madeux from Arizona, was given the experimental treatment to try to correct a defect in his DNA that causes Hunter's syndrome, in which patients are born without the genetic instructions for an enzyme that breaks down long sugary molecules called mucopolysaccharides.

This bold attempt has raised hopes of permanently changing a person's DNA to cure a disease.

It is too soon to know whether or not the gene-editing has worked in the patient's case, says one of the doctors.

Patients need regular enzyme replacement therapy to break down the mucopolysaccharides but in this patient's case, an experimental treatment was given to rewrite his DNA to give him the instructions for making the enzyme.

The therapy contains two molecular scissors, called zinc finger nucleases, that cut the DNA at two precise spots.

This creates an opening for a new piece of DNA, containing the desired instructions, to be inserted into the patient's genetic code.

The genetic therapy has been designed so it becomes active only once it gets inside his liver cells.