Hu­man em­bryos edited to stop dis­ease

Daily Trust - - NEWS -

Sci­en­tists have, for the first time, suc­cess­fully freed em­bryos of a piece of faulty DNA that causes deadly heart dis­ease to run in fam­i­lies.

It po­ten­tially opens the door to prevent­ing 10,000 disor­ders that are passed down the gen­er­a­tions.

The US and South Korean team al­lowed the em­bryos to de­velop for five days be­fore stop­ping the ex­per­i­ment.

The study hints at the fu­ture of medicine, but also pro­vokes deep ques­tions about what is morally right.

Sci­ence is go­ing through a golden age in edit­ing DNA thanks to a new tech­nol­ogy called Crispr, named break­through of the year in just 2015.

Its ap­pli­ca­tions in medicine are vast and in­clude the idea of wip­ing out ge­netic faults that cause dis­eases from cys­tic fi­bro­sis to breast cancer.

US teams at Ore­gon Health and Sci­ence Univer­sity and the Salk In­sti­tute along with the In­sti­tute for Ba­sic Sci­ence in South Korea fo­cused on hy­per­trophic car­diomy­opa­thy.

The disor­der is com­mon, af­fect­ing one in every 500 peo­ple, and can lead to the heart sud­denly stop­ping beat­ing.

It is caused by an er­ror in a sin­gle gene (an in­struc­tion in the DNA), and any­one car­ry­ing it has a 50-50 chance of pass­ing it on to their chil­dren.

In the study, de­scribed in the jour­nal Na­ture, the ge­netic re­pair hap­pened dur­ing con­cep­tion.

Sperm from a man with hy­per­trophic car­diomy­opa­thy was in­jected into healthy do­nated eggs along­side Crispr tech­nol­ogy to cor­rect the de­fect.

It did not work all the time, but 72% of em­bryos were free from dis­ease­caus­ing mu­ta­tions.

Dr Shoukhrat Mi­tal­ipov, a key fig­ure in the re­search team, said: “Every gen­er­a­tion on would carry this re­pair be­cause we’ve re­moved the dis­ease­caus­ing gene vari­ant from that fam­ily’s lin­eage.

“By us­ing this tech­nique, it’s pos­si­ble to re­duce the bur­den of this her­i­ta­ble dis­ease on the fam­ily and even­tu­ally the hu­man pop­u­la­tion.”

There have been mul­ti­ple at­tempts be­fore, in­clud­ing, in 2015, teams in China us­ing Crispr-tech­nol­ogy to cor­rect de­fects that lead to blood disor­ders.

But they could not cor­rect every cell, so the em­bryo was a “mo­saic” of healthy and dis­eased cells.

Their ap­proach also led to other parts of the ge­netic code be­com­ing mu­tated.

Those tech­ni­cal ob­sta­cles have been over­come in the lat­est re­search.

How­ever, this is not about to be­come rou­tine prac­tice.

The big­gest ques­tion is one of safety, and that can be an­swered only by far more ex­ten­sive re­search.

There are also ques­tions about when it would be worth do­ing - em­bryos can al­ready be screened for dis­ease through pre-im­plan­ta­tion ge­netic di­ag­no­sis. (BBC)

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