Genetic testing at birth? Researchers are now studying the possibility

Dr. Neal Sondheimer is a medical director of Newborn Screening Ontario at CHEO. Photo by JEAN LEVAC /POSTMEDIA

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Just a few days after her daughter was born, Robyn Miller was awoken by frantic knocking at the front door. Her midwife was there with an urgent message to contact SickKids Hospital. Specialists were concerned about the results of a blood screening test her newborn had been given shortly after birth.

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Miller, her husband Briam, and their baby drove from their home in Huntsville to Toronto. Testing at the children’s hospital confirmed those concerns: Their daughter had phenylketonuria (PKU), a rare metabolic disorder that prevents the body from breaking down an amino acid found in protein-rich foods. Without early treatment, the disorder can result in irreversible brain damage, severe intellectual disability and seizures.

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Robyn said they headed to the hospital certain the suspicious test was just a fluke.

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“We’ll go in, they’ll do tests and we’ll leave tonight and it won’t be any different,” she thought at the time. “Safe to say, that was not the case. Our world completely turned over when we got the diagnosis.”

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And it almost didn’t happen.

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When Briam first learned about dried blood spot screening of newborns, he admits he was skeptical. He initially hesitated, thinking it would give his daughter no more than a risk assessment for certain illnesses she might get over her lifetime. After further discussions and clarifications, both Robyn and Briam were convinced.

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“I turned down doing that testing for our daughter,” he said. “Luckily, they continued to educate me on what it actually was and the importance of it.”

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Now they know the newborn screening, which tests for serious but treatable diseases that might not otherwise be identified early, helped save their daughter. The couple asked that she not be named to protect her privacy.

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Robyn and Briam Miller’s daughter was diagnosed with a rare but treatable disorder through newborn testing. Photo by NEWBORN SCREENING ONTARIO /PROVIDED

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The program that changed their daughter’s life could now be expanding to include significantly more treatable diseases. Researchers are starting to explore what could become the biggest expansion in newborn screening in Ontario’s history — to include genetic testing.

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A research project to look at whether genomic newborn screening could be part of Ontario’s standard screening program is just getting underway. The research is the first of its kind in North America.

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The study will offer whole genome screening to 10,000 Ontario newborns, using the same dried blood spot already collected for newborn screening, with consent.

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The INFANT study, as it is called, will use non-commercial sequencing to look for pathogenic variants in 223 genes linked to serious but treatable early-onset childhood diseases.

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The disease the Miller’s young daughter was diagnosed with, PKU, was the start of universal newborn screening in Ontario in 1965. At first, it was the only one babies were screened for, but the program has expanded from there.

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Today, the program run by CHEO-based Newborn Screening Ontario, established 20 years ago, screens newborns for more than 25 treatable conditions. Those include metabolic diseases, endocrine diseases, sickle cell disease, cystic fibrosis and more.

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Every year, roughly 145,000 Ontario babies are tested using blood taken from their heel 24 to 48 hours after birth. Roughly 350 of those infants are identified with a treatable disease because of the screening. In 2024, the Miller’s baby was among them.