Testing Baby DNA: BabySeq study Finds 9% of Babies Have A Monogenic Disease:

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Testing Baby DNA:  BabySeq Study Finds 9% of Babies Have Monogenic Disease Impacting One Gene.

BabySeq  is a pioneering study that is exploring what happens when extensive DNA analysis searching for potential childhood disorders is performed on newborns.

One child had a partial version of the disorder — biotinidase deficiency — and the deep DNA testing her parents had signed her up for, known as whole-exome sequencing, had clinched the diagnosis. This child takes biotin which will prevent many complications which she would have had without biotin.

Getting out in front of disease is the ultimate goal of DNA screening like the BabySeq project, says Dr. Robert Green, its joint director and a Harvard Medical School professor.

“We want to take a medical system that’s mostly reactive and all about ‘sick care,’ and move it to be proactive and all about prevention,” he says.

BabySeq, based mainly at Brigham and Women’s Hospital and Boston Children’s Hospital, is federally funded. It targets genes likely to lead to problems in childhood and that lend themselves to possible action.

In the latest findings, published Thursday in the American Journal of Human Genetics, those mutations turn out to be surprisingly common, turning up in more than 9 percent of babies tested.

That 9 percent of infants are at risk “for what we call monogenic diseases — or diseases that are caused by a change in a single gene — is really an unprecedented and pretty startling finding,” Dr. Green says.

The study compares 159 babies who were randomly assigned to have their DNA sequenced, and 157 assigned only to standard newborn screening, a biochemical test performed on a drop of blood.

Among the 15 sequenced babies whose DNA raised a red flag, it was most often for a mutation linked to risky heart conditions or hearing loss. It is not clear whether the disorders linked to the genes will actually develop in each case.

About one in every 10 people has some sort of rare disease, says Dr. Alan Beggs, director of the Manton Center for Orphan Disease Research at Boston Children’s Hospital and the paper’s senior author.

“However, we don’t expect one in 10 people to have a genetic disease with a mutation that we can find,” he says. So one goal “is to try to understand which of these are actually going to potentially cause disease. And what we can do to help mitigate the effects of that in the future.”

As DNA sequencing becomes more common, BabySeq aims to answer an array of questions: How does it affect a child’s care? How does it affect the family? How does it impact the costs of care? What do doctors do with the information?

Whether DNA screening should be done on healthy babies is a topic of lively debate, including concerns that genetic findings may cause anxiety and overtreatment.

Dr. Alan Beggs, director of the Manton Center for Orphan Disease Research at Boston Children’s Hospital was one of the leaders of the BabySeq trial in Boston.