As Prescribed: UCSF doctors use genetic testing to treat fetuses before they're born


SAN FRANCISCO (KCBS RADIO) – Newborns with a sudden critical illness can be difficult for doctors to treat – and the cause of their illnesses can be hard to determine. However, a new test offered at UCSF aims to remove some of the mystery.

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“Rapid genome sequencing is a newly introduced test that looks at all of the genes in a person, whether that’s a pregnant patient or a newborn baby,” said Dr. Mary Norton, a perinatologist and clinical geneticist at UCSF Medical Center’s Prenatal Diagnostic Center.

She joined KCBS Radio’s Alice Wertz for the latest “As Prescribed” episode.

UCSF implemented on-site rapid whole genome sequencing, or rWGS, earlier this year. This testing can help babies get diagnosed – and allow treatment programs to get started – even before they’re born.

It works by analyzing the entire DNA sequence of a fetus or infant. Other genetic tests focus on individual genes or limited selections of genes.

“We can even look at a fetus and look at all those genes to determine if there’s something there that might explain things that we’re seeing on [an] ultrasound,” Norton said.

UCSF experts explained that, without this rapid testing, it can take months or years for infants to get diagnosed. That longer process then delays treatment.
Thanks to rapid testing, some treatments can even begin in utero.

With the rapid genome sequencing, we find an answer in… 35% of cases, which is really quite high, and some but not all of those turn out to be things for which there is a simple treatment that we can that we can use,” said Norton. “For example, there may be a fetus that has severe anemia – and some forms of anemia or low blood counts are inherited. And it’s pretty well known that we can easily give a blood transfusion to a fetus.”

UCSF gave another example: an infant named Charlotte has a mysterious illness and was sent to UCSF from California’s Central Valley. Rapid testing revealed that she had a rare genetic disease called prolidase deficiency inherited from her parents, who were unaware they were carriers.

Norton said the she believes rapid testing will be increasingly employed at other high-risk centers in the future.

Listen to this week’s “As Prescribed” to learn more. You can also listen to last week’s “As Prescribed” about a new treatment for patients with a condition that can develop into breast cancer here.

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