Disease gene 'edited' in human embryos

Disease gene 'edited' in human embryos

The scientists said the procedure was surprisingly effective and that clinical trials could eventually be considered.

Embryonic gene editing should move forward "only for compelling reasons and under strict oversight", ethics experts said in a recent report from National Academy of Sciences and the National Academy of Medicine.

Injecting Cas9 along with the sperm - before an egg had a chance to replicate its DNA - produced only one patchwork embryo.

Though the scientists only edited out mutations that could cause diseases, it modified the nuclear DNA that sits right at the heart of the cell that also influences personal characteristics such as intelligence, height, facial appearance and eye colour.

Then again, the gene-editing tool could be used to eliminate horrific, costly diseases like cystic fibrosis, sickle cell anemia, certain cancers and heart diseases, and perhaps even offer protection against Alzheimer's. "Every generation on would carry this fix because we've removed the disease-causing gene variant from that family's lineage".

"There is still work to do to improve the efficiency", Dr. Mitalipov told Time. "There is still a long road ahead particularly if you want to do it in a really regulated way". Using this method, they were able to achieve a high yield of homozygous embryos carrying the wild-type MYBPC3 gene without evidence of off-target mutations.

"This is the first that has been demonstrated as safe and working", said Belmonte, a professor at the Salk Institute for Biological Studies' gene expression laboratory in La Jolla, California. The defective gene causes hypertrophic cardiomyopathy, the most common cause of sudden cardiac arrest in young athletes.

The researchers started with human embryos created from 12 healthy female donors and sperm from a male volunteer who carried the MYBOC3 gene. They found that once the paternal gene was excised, the genetic material originating from the mother (i.e., the homologous wild-type maternal gene) was more easily substituted than the synthetic DNA the scientists attempted to introduce.

"It was easy", Mitalipov said. Of 54 injected embryos, 13 were patchwork, or mosaic, embryos with some repaired and some unrepaired cells.

Molecular scissors known as CRISPR/Cas9 corrected a gene defect that can lead to heart failure. The healthy embryos were then allowed to grow further - but only for a few days. The study demonstrated that human embryos could effectively fix themselves after a break in mutant genes by using the normal copy of the gene from a second parent as a template. But those embryos were abnormal and nonviable, and there were far fewer than the number used in the USA study. "But I think that's possible to do".

Current treatment options for HCM provide mostly symptomatic relief without addressing the genetic cause of the disease.

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I'll know exactly where we stand, but I don't know how much that ever helps you. "I just had to turn it around", McIlroy said. Kuchar got up and down on 17 to trim Spieth's lead to two, but he couldn't answer the dagger on the last.

The research, which was leaked in part last week, struck home for Marlo Urbina, a mother of 8-year-old twins in Portland.

Darnovsky is not alone in her unease.

"She has early onset dementia", Urbina said.

"We need more debate", Wu said. The eggs used to produce the zygotes did not carry that gene mutation.

The work at OHSU was paid for by the hospital.

Researchers at collaborating labs in South Korea and China also carried out thorough checks of the embryos' DNA to see if there had been mistakes elsewhere.

There are also questions about when it would be worth doing - embryos can already be screened for disease through pre-implantation genetic diagnosis. According to Shoukhrat Mitalipov, who led the latest research, gene editing could bolster the number of healthy embryos available for doctors to implant.

Scientists not involved in the project hailed it a landmark in genetics. This technique would only work in the second case. Mitalipov would like 100 percent.

Some worry this kind of technology could lead to "designer babies", where parents alter their offspring's DNA for more than just hereditary diseases. He adds that the research is "a big breakthrough".

"The genome editing tools are now not sufficiently efficient and specific to be reliable, and regulatory and oversight processes have not been established", Carroll said, adding that the work on the new study was "well-done" and "well-presented".

"Regular clinics are not equipped and don't have the expertise to do it", he said. They were able to correct the defect in an astonishing two thirds of embryos, all without causing a mutation that could prove unsafe.