dglobalnews.com In a scientific first, disease gene 'edited' in human embryos
Published: Fri, August 04, 2017
Medical | By Benjamin Edwards

In a scientific first, disease gene 'edited' in human embryos

In a scientific first, disease gene 'edited' in human embryos

With advances in stem cell technologies and gene editing, researchers are finally starting to address disease-causing mutations that impact potentially millions of people. According to a report published Wednesday in the journal Nature, the researchers were able to demonstrate that it is possible to safely and efficiently correct defective genes that cause inherited diseases.

Speculation swirled after reports came out last week that a group of USA scientists had CRISPR'd human embryos for the first time.

An worldwide group of 11 organizations, including the American Society of Human Genetics and Britain's Wellcome Trust, on Wednesday issued a policy statement recommending against genome editing that culminates in human implantation and pregnancy, while supporting publicly funded research into its potential clinical applications. The tools, called CRISPR, included an enzyme primed to target and snip out the bad gene.

With strict regulation and an emphasis on ethical experimentation, the scientific breakthroughs that can be realized through these experiments could not only eradicate disorders like cystic fibrosis, muscular atrophy and even color blindness, but allow us to learn more about human development than ever before.

Critics of the study were quick to allege that the research team - whose work can not be taken much further in the United States given legal limitations - had already pushed the boundaries too far. Researchers worked with healthy egg cells, donated by women, and sperm of a man affected by hypertrophic cardiomyopathy. The researchers used well over a hundred healthy donor eggs, fertilised with sperm from a donor with the gene for hypertrophic cardiomyopathy.

In the landmark trials, the United States and South Korean team demonstrated how they can use CRISPR technology (a revolutionary tool used to edit DNA) to successfully free the embryo from a faulty piece of DNA introduced by one of the parents at conception. He then introduced CRISPR to splice out the mutated gene in more than 50 embryos just after the sperm fertilized the eggs, when the embryos were still just one cell.

The team also uncovered a new and potentially important DNA fix mechanism that takes place in early embryo development.

The procedure involved "correcting" the DNA of one-cell embryos using CRISPR to remove the MYBPC3 gene.

DNA of human embryos edited for 1st time in US
A scientist who is familiar with the project but chose to remain anonymous said: "It is proof of principle that it can work ". Technology Review could not determine which disease genes had been chosen for editing.

Previous attempts to extend this technique to human embryos, in China, are reported to have run into problems with mosaicism, where some, but not all, the copies of the relevant gene are changed, so that the embryo develops with different regions expressing different variants of the same gene.

"The question that will be most debated is whether the same principle of modifying the genes of an embryo in vitro is acceptable", analyzed by an independent expert, professor Darren Griffin (University of Kent), quoted by the Science Media Centre.

Gene editing is controversial because it evokes a future in which humans can order "designer" babies with specific features - blonde hair, athleticism, perhaps even intelligence.

Genetics and ethics experts not involved in the work say it's a critical first step - but just one step - toward eventually testing the process in pregnancy, something now prohibited by US policy. In no other field of science does that age-old adage ring true than when it comes to fertility and the study of embryos, genetics and testing.

The goal: to cut the defective DNA to bring about its fix.

The National Academy of Sciences released a report a year ago urging caution when using CRISPR to permanently alter inherited genes - exactly the thing done by the new study.

Asked about critics of genetic manipulation, he said his work has nothing to do with the creation of "designer babies" through genetic manipulation to give the children traits desired by the parents.

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