'Rebooting' DNA may halt hereditary illness

THE onset of devastating disorders such as cystic fibrosis, muscular dystrophy and some cancers could be prevented after scientists discovered how to change the human genetic code.

Their discovery has been hailed as "the new miracle of modern medicine" that could be used to stop people developing potentially fatal hereditary conditions.

The genetic code is the set of instructions that tell a cell how to make a specific protein.

Central to the body's protein production process is a molecule known as messenger RNA (mRNA), which takes these instructions from DNA and directs the steps necessary to build a protein.

For the first time, researchers at the University of Rochester Medical Centre, New York State, have been able to artificially modify mRNA, and change the original instructions for creating the protein.

This results in a different protein than was originally called for, according to the study published in the journal Nature.

Chairman of the university's biochemistry and biophysics department Robert Bambara said: "The ability to manipulate the production of a protein from a particular gene is the new miracle of modern medicine.

"This is a really powerful concept that can be used to try to suppress the tendency of individuals to get certain debilitating, and sometimes fatal, genetic diseases that will forever change their lives."

Protein production is far from perfect and mutations or mistakes in DNA and mRNA sequences can lead to flawed proteins that have the potential to cause serious harm.

In the study, researchers focused on a common type of mutation that occurs when an mRNA molecule contains a premature "stop" signal, known as a "premature stop codon".

A premature stop codon orders a cell to stop reading the genetic instructions part-way through the process, resulting in the creation of an incomplete, shortened protein.

Researchers were able to alter mRNA in a way that turned a "stop" signal into a "go" signal.

As a result, the cell could read the genetic instructions all the way through and create a normal, full-length protein.

The team produced these results both in the test tube and also in live yeast cells.

The study's lead author, Yi-Tao Yu, said: "This is a very exciting finding.

"No-one ever imagined that you could alter a stop codon the way we have and allow translation to continue uninterrupted like it was never there in the first place."

It was estimated that about a third of genetic diseases are caused by the presence of premature stop codons that result in shortened proteins.The results could aid the development of treatments designed to help the body override stop codons and produce adequate amounts of full-length proteins, whose absence causes diseases such as cystic fibrosis and contributes to different types of cancer.

Cystic fibrosis affects around 9,000 people in the UK, around 700 in Scotland, while muscular dystrophy and related muscle diseases affect more than 70,000 people in Britain.