Oct. 29 (UPI) -- Researchers testing technology to edit DNA during human development -- with the hope of preventing disease -- have found that the process often eliminates an entire section of genetic material and could threaten the health of the baby, according to a study published Thursday in the journal Cell.
The technology, the CRISPR/Cas9 genome editing method, allows scientists to make precise changes to the DNA of cells.
Chromosomes are DNA molecules that carry genetic information from parent to child, and they exist in matching pairs, with one for each pair inherited from each biological parent.
This chromosome loss, the result of a "single break" in embryonic DNA during the editing process, could have a significant impact on the healthy development of the baby, the researchers said.
"And this loss of the chromosome is very frequent," study co-author Michael Zuccaro, a doctoral candidate at Columbia University Vagelos College of Physicians and Surgeons, said in a statement.
The first use of CRISPR in human embryos was reported in 2015. In 2017, researchers reported the successful correction of a heart disease-causing mutation in normal human embryos using the approach.
A year later, researchers claimed to have used the method in a pair of Chinese twins, with the goal of making them immune to HIV. However, the long-term effects of the procedure in these children remains unknown.
The new study documents tests of the gene editing method's effects on early-stage human embryos, researchers attempted to correct a genetic mutation called EYS -- or the eyes shut homolog -- that causes hereditary blindness.
The researchers found, however, that the method can lead to the loss of part of or an entire chromosome, Zuccaro and his colleagues said.
"Our study shows that CRISPR/Cas9 is not yet ready for clinical use to correct mutations at this stage of human development," study co-author Dieter Egli said.
"If our results had been known two years ago, I doubt that anyone would have gone ahead with an attempt to use CRISPR to edit a gene in a human embryo in the clinic."
"Our hope is that these cautionary findings should discourage premature clinical application of this important technology," said Egli, assistant professor of developmental cell biology at Columbia University.