Scientists cheer vote to allow three-person embryos

Ewen Calloway in Nature:

In a historic decision, the United Kingdom's House of Commons has voted to legalize a gene-therapy technique that could help women to avoid passing genetic defects onto their children. The vote, decided by 382 members of parliament casting in favour and 128 against, is expected to lead to the United Kingdom becoming the first country in the world to allow the transfer of DNA from diseased human eggs to healthy ones in the clinic.

This technique, known as mitochondrial replacement or three-person in vitro fertilization, aims to prevent women passing on harmful mutations in their mitochondria, the cell's energy-producing structures. An estimated 1 in 5,000 children are born with diseases caused by such mutations, which typically affect power-hungry tissues such as the brain, heart and muscles. All mitochondrial DNA is inherited from the mother, and some women carry harmful mitochondrial mutations without experiencing symptoms themselves. “It's great news for the patients with mitochondrial disease. It gives them real hopes and that's just fantastic,” says Doug Turnbull, a neurologist at Newcastle University, UK, who has led the effort to bring mitochondrial replacement to the clinic.

More here.