Repair in the uterus
Some genetic diseases damage the fetus in the womb. Prenatal gene therapy could provide a remedy.
In July 2018, researchers reported using gene therapy to stop a deadly brain disease in mice-before the animals were even born. The rodents carried a defective version of the GBA gene; this contains the blueprint of an enzyme that breaks down certain lipid compounds called glucocerebrosides. If the enzyme is missing, these molecules accumulate in the brain and cause irreparable damage there. Animals affected by the genetic defect usually die within 14 days of birth. Their disease is analogous to human Gaucher syndrome, so the mice are used as animal models to study this condition. Gaucher syndrome can vary in severity, so doctors divide it into three types. In type II, the affected children usually do not get older than two years.
In the experiment with GBA-defective mice, the scientists injected certain viruses, which contained an intact version of the GBA gene, into the brains of the mouse fetuses around halfway through the pregnancy. The animals treated in this way were born without complications and lived for at least four and a half months without showing any signs of brain damage. "This represents an extremely significant increase in lifespan," said Jerry Chan, a specialist in prenatal medicine at Duke-NUS Medical School (Singapore), one of the co-authors. In addition, the scientists also treated he althy macaque fetuses with their gene therapy method - and thus demonstrated that a corresponding intervention can be carried out in these primates, which are much more similar to humans in terms of size and physiology than mice, without serious side effects occurring."We tried to demonstrate experimentally as meaningfully as possible and at the same time ethically impeccable a way of transferring our gene therapy approach to clinical application in humans," says Simon Waddington, gene therapy researcher at University College London and leader of the study …