US researchers raise hopes on genetic therapy to prevent inherited diseases

Researchers in the US have raised hopes for a simple genetic therapy that could prevent devastating diseases being passed on from mothers to their children.

A team at the Salk Institute in California demonstrated in mice that a single injection into embryos could rewrite faults in the DNA of mitochondria, the biological batteries that are needed to keep tissues healthy.

Most cells in the body carry hundreds or thousands of mitochondria, which are inherited only from mothers. Harmful mutations in mitochondrial DNA cause progressive and often fatal diseases that typically affect the heart, brain and muscles.

The US researchers showed that simple and widely available genome editing procedures could correct faulty mitochondria in the mouse embryos and then dramatically reduce the number they then passed down to future generations.

Many mitochondrial diseases only take hold if the person, or their specific organs, carry a sufficiently high proportion of the faulty mitochondria, said Juan Carlos Izpisua Belmonte, who led the work.

"This technology is not perfect; it cannot eliminate all the bad DNA, but by eliminating some, it'll be enough to prevent the transmission of these diseases to the kids of affected mothers," said Belmonte.