Genetic testing is taking medicine to an all new extreme

BY: Ellie Kincaid
Preventing disease is a standard goal of medicine.

But a new technology takes it farther than we normally do by preventing a potential person with a genetic disease from being born at all, George Annas, a bioethicist and health lawyer at Boston University and author of "Genomic Messages," tells Business Insider.

"It's an extreme," Annas says.

The technology, called preimplantation genetic diagnosis (PGD), can be used in conjunction with in-vitro fertilization to test for genetic disease and genetic predispositions, and can even determine sex - all before a woman is actually pregnant.

How it works IVF is a procedure in which eggs are taken from a woman's ovaries and fertilized with sperm in a petri dish. Then one or more fertilized embryos are placed in the woman's uterus, where one will hopefully implant and grow into a baby.

During the process of IVF, multiple embryos are created in the lab from a couple's eggs and sperm. Before transferring any embryos to the woman's uterus, doctors can perform PGD by taking one cell from each embryo and analyzing the DNA for disease-causing mutations.

In its practice committee opinion on genetic testing for embryos created through IVF, the American Society for Reproductive Medicine calls PGD "a major scientific advance" for couples whose children risk inheriting a terrible genetic disease. It means people with diseases like Huntingdon's don't have to worry about passing it on to their children.

That "major scientific advance" is pushing disease prevention farther than we've ever been able to before.

'An extreme' in action One gene mutation makes the brains of approximately 30,000 Americans begin breaking down in their 30s or 40s, causing problems with movement, thinking, and mood, and initiating a progressive decline that can't be halted with any known treatment.

That's the gene mutation behind Huntington's disease, and parents who have it have a 50% chance of passing it down to each child they have.

Since the disease is caused by a mutation in a single gene, scientists can perform a DNA test to confirm a diagnosis or predict whether someone with a family history of the disease will have it too. But until recently, there's been no way to prevent Huntingon's disease.

Some people with Hungtington's in their family would roll the dice; many others simply decided not have children at all.

Today, if a couple affected by Huntington's disease doesn't want to risk passing the disease down to a child, they can try to conceive through in vitro fertilization (IVF), using PGD. That special layer of genetic testing, however "extreme" it may seem, changes everything: It can all but ensure they won't have child who suffers from the disease.