Scientists Correct Disease-Causing Gene Mutation in Human Embryos

Embryos after co-injection of a gene-correcting enzyme and sperm donor with a genetic mutation known to cause hypertrophic cardiomyopathy (OHSU)
Embryos after co-injection of a gene-correcting enzyme and sperm donor with a genetic mutation known to cause hypertrophic cardiomyopathy (OHSU)

Scientists have for the first time successfully corrected a disease-causing gene mutation in donated clinical-quality human eggs. The technique used in the study is detailed in the journal Nature, and it could have momentous implications for inherited genetic disorders.

“If proven safe, this technique could potentially decrease the number of cycles needed for people trying to have children free of genetic disease,” said co-author of the study Paula Amato, MD, associate professor of obstetrics and gynecology at the Oregon Health & Science University (OHSU), where the study was conducted.

The study focused on the genetic mutation that causes hypertrophic cardiomyopathy, which effects an estimated 1 in 500 individuals. Using the gene-editing tool CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) the researchers worked with healthy donated human oocytes and sperm carrying the genetic mutation that causes cardiomyopathy.

CRISPR makes it possible to snip a specific target sequence on a mutant gene. The study demonstrated that human embryos could effectively repair themselves after a break in mutant genes by using the normal copy of the gene from a second parent as a template. Mosaicism — in which not all cells are repaired — was overcome by co-injecting the repair enzyme and the mutation-carrying sperm into the donor oocyte, resulting in all cells being mutation-free.

With further advancements the potential could exist to apply the technique to other inherited disease-causing mutations such as breast cancer and cystic fibrosis.

The research raises obvious concerns around the ethics of genetic engineering. The consequences of the research may not be felt for quite a while yet as clinical trials remain a long way off, and are in fact currently impermissible under federal law.

“The ethical considerations of moving this technology to clinical trials are complex and deserve significant public engagement before we can answer the broader question of whether it's in humanity's interest to alter human genes for future generations,” said Daniel Dorsa, PhD, SVP of research at OHSU.

For more information visit OHSU.edu.