New genetic test aims to prevent some diseases

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by CLARA TUMA / KVUE News

kvue.com

Posted on January 25, 2010 at 7:43 PM

In the movie, "Extraordinary Measures," father Brendon Fraser frantically tries to find a cure for the often-deadly Pompe disease that is killing his children.

At the Texas Fertility Center, doctors are working to prevent parents from being faced with that kind of life-or-death situation.

The center is the first in Austin to offer a new genetic test that can help prevent children from being born with any of 109 genetic diseases The test gives would-be parents full genetic information about their risks of bearing children with specific diseases.

"The genetic testing is revolutionary," says Dr. Kaylen Silverberg, medical director at the center and a reproductive endocrinologist. "In the past, we have not been able to screen couples effectively for as many diseases as we have now, so we've had to draw blood, and screen for one disease here and one disease there."

The new saliva swab test is from California-based Counsyl. It tests saliva from both prospective parents to determine the likelihood their offspring will be born with more than 100 diseases.

"We can look at everything from cystic fibrosis to sickle cell disease to tasacs disease, canavans disease," Silverberg says. "These diseases run the gamut. They vary from diseases that would have mild or minimal impact on the life of a child, all the way to being fatal. Babies with tasacs rarely live beyond early childhood."

Parents are then armed with valuable genetic information before deciding how or whether to proceed with having children, he says.

"We can give them a realistic idea of what their risk is for having a baby with any specific abnormality that's covered by this," Silverberg says.

Reproductive endocrinologist Lisa Hansard often lets parents know they are at risk for diseases for which they have no family history.

"It's actually giving couples the chance to evaluate their own risks," she says.

The saliva tests cost roughly half of the $1,500 to $2,000 that genetic blood tests cost.

After fertilization, the center is also able to remove and look at specific cells to determine whether disease is present.

"We can actually remove a single cell from the embryo and screen it and know whether that embryo is affected or not affected," Silverberg says. "So we really have the ability to eradicate a lot of familiar diseases that in the past we had no ability to do anything but treat after birth."

The center then implants cells that don't carry disease back in the mother, and freezes the other cells for possible use in the future.

Mom-to-be Jennifer Montgomery is due to deliver her first daughter any day now.

Before she became pregnant, both she and her husband had blood tests to determine the likelihood of passing on a disease to a child. To their surprise discovered they were both carriers of cystic fibrosis.

"No one on either side of our family has or has ever had cystic fibrosis," she says.

Knowing they had a high chance of having a child with cystic fibrosis, they decided to a procedure in which fertilized cells were removed and studied for the presence of the disease.

"We knew we had a relatively good chance of having a child with cystic fibrosis if we didn't use any intervention, and we didn't want to go that route," she says. "We had 10 embryos and found out that five of them had cystic fibrosis. Three of the others were carriers."

Some of the non-diseased embryos were implanted, and Montgomery is now pregnant with a girl she knows does not have cystic fibrosis. She does, however, know the child is a carrier of the disease.

"As excited as we are to have a child, I can't imagine her being born finding out that she had cystic fibrosis, and then thinking maybe there was something I could have done about that," Montgomery says.

She says the decisions involving testing for genetic diseases are difficult, and that there's not single answer for every family.

But, she says, for her, the decision to intervene was the right one.

"We're very comfortable with our decision," she says. 

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