Genomic newborn screening catches rare diseases before symptoms start, with early trials flagging treatable conditions in up to 4% of infants
核心洞察
Whole-genome newborn screening studies such as GUARDIAN, BabyScreen+, and BabyDetect are identifying serious genetic conditions that conventional screening would miss in roughly 1.6% to 4% of infants.
Preliminary GUARDIAN data from 15,000 newborns confirmed genetic conditions in 2.7% of participants, with more than 90% of detected diseases missed by traditional testing methods.
Early diagnosis has enabled life-saving interventions, including a bone-marrow transplant in a six-month-old with familial HLH and pre-symptomatic treatment for a six-month-old with Batten disease (搜索).
A six-month-old girl in New York was diagnosed with Batten disease (搜索), a rare and fatal genetic condition affecting the nervous system, before she ever showed symptoms. For her specific subtype of Batten, symptoms such as sudden vision changes or seizures may not have appeared for several more years—by which point irreversible neurological damage would already have occurred. Her diagnosis came through the Genomic Uniform-screening Against Rare Diseases In All Newborns (GUARDIAN) Study, a large-scale research initiative launched in New York out of Columbia University with funding from Sanofi, Illumina, and GeneDx (搜索).
Led by clinical and molecular geneticist Dr. Wendy Chung, the GUARDIAN program set an ambitious goal: provide free whole-genome sequencing to screen up to 100,000 newborns across New York for rare genetic conditions. Standard newborn screening—which nearly every baby born in the U.S. already undergoes—typically tests for between 30 and 50 diseases. GUARDIAN screens for 450 genetic conditions, and it does not require any additional blood samples.
Early results across global studies
Preliminary findings published in JAMA showed that among the first 4,000 newborns screened in GUARDIAN, the test identified serious genetic conditions in just under 4% of children, with more than 90% of those diseases missed by traditional testing methods. At a conference last October, researchers shared preliminary results from 15,000 newborn participants out of a planned 100,000: whole-genome sequencing identified 411 infants (2.7%) whose screening results were subsequently confirmed through diagnostic testing. The vast majority were not identified through current newborn screening because their conditions are not included in those tests. In some cases, the findings prompted life-saving interventions, including bone-marrow transplants.
Several studies published early findings in 2025 with comparable results. The BabyScreen+ study in Australia screened 1,000 newborns and reported confirmed findings in 1.6% of participants. In Belgium, the BabyDetect study confirmed genetic conditions in 1.8% of nearly 4,000 infants, including 0.8% whose conditions would have been missed by conventional newborn screening.
"Even though we're based in different health-care systems, and we've taken some slightly different approaches to some of the components, many of the results are actually quite similar, which is reassuring," said Zornitza Stark, a clinical geneticist at the Murdoch Children's Research Institute in Parkville, Australia, and co-leader of the BabyScreen+ study.
A chance to intervene before damage occurs
The case of the six-month-old girl with Batten disease (搜索) illustrates the clinical value of pre-symptomatic detection. After receiving her diagnosis, her parents and doctors decided to start a treatment they hope could delay or even prevent some of the neurological damage associated with Batten. It is too early to say whether their efforts will succeed, but because of GUARDIAN, the family at least has a chance.
A similar story unfolded in Australia, where two-year-old Giselle Ghattas was enrolled in the BabyScreen+ study by her parents, Justin Ghattas and Scarlett Morwood, after they came across the study on social media. Giselle has familial haemophagocytic lymphohistiocytosis (搜索) (HLH), a rare genetic disorder that causes fever and inflammation and can spiral into organ failure, neurological damage, and death in as little as months if untreated. Because HLH is rare and variable, clinicians often misdiagnose it or fail to catch it early.
"If I had just kept scrolling on Facebook and not joined, then we'd probably still be, potentially even now, working out: 'What's wrong with her?'" said Ghattas. Instead, Giselle received a bone-marrow transplant at six months old, and despite some complications, she has recovered and begun to thrive. According to her physicians, she will probably not need any more treatment beyond routine monitoring.
The scale of the opportunity
Current newborn-screening practices in many parts of the world use a dried blood spot taken from the heel shortly after birth, screening for congenital disorders mostly through chemical analysis of proteins and metabolites rather than gene sequencing. U.S. guidelines recommend testing for 66 conditions, mainly metabolic disorders, while France tests for 16 and the United Kingdom screens for 10. Of the nearly 3.6 million infants born in the United States each year, 98% undergo this kind of screening, and it has been predicted that roughly 6,600—about 1 in 600—will test positive for a condition.
Genomic newborn screening would drastically expand what can be detected. Using DNA from the same dried blood spots collected for conventional screening, pilot studies are sequencing hundreds of genes or even the entire genome, with some screening for more than 700 disorders. If implemented broadly, this approach could identify thousands—perhaps millions—of children worldwide with rare genetic diseases.
The BabySeq Project, initiated in 2013 and co-led by Robert Green, a medical geneticist at Harvard Medical School, was one of the first studies to evaluate genomic sequencing in healthy newborns. Across two independent BabySeq trials, around 1,045 infants were enrolled, including 432 chosen at random to undergo genomic sequencing. Among the infants whose genes were sequenced, approximately 11% had disease-associated genetic variants, and roughly one-third were already showing early signs of disease.
Gene-list decisions and unresolved questions
In their effort to maximize benefits, researchers must first decide which genes belong on the panel—a question that has proved surprisingly contentious. BabyScreen+ analyses 605 genes, whereas BabyDetect screens 405. GUARDIAN began with about 250 genes before expanding to 450, while North Carolina's Early Check program evaluates 169. Most programs focus on severe childhood-onset disorders that have some form of intervention.
As studies have grown, researchers have uncovered the limits of current knowledge about the relationship between genetic variants and disease. In GUARDIAN, infants with variants in the epilepsy-associated gene SCN1A (搜索) differed notably from one another in the age of onset for seizures. Even variants in well-characterized genes do not always reliably predict disease, and disease databases do not always agree on how harmful a given variant is.
"Understanding genotype–phenotype correlations and fine-tuning reporting requires very large numbers of individuals to be tested," said Stark. "We're not going to get there unless we actually test thousands, if not millions, of individuals."
One central aim of these studies is determining which genetic changes cause disease and which prove benign. In GUARDIAN, 64 of 475 infants flagged initially as potentially having a genetic disorder showed no signs of disease at the time of confirmatory testing. The Early Check study reported 22 such cases among 50 flagged infants, whereas BabyScreen+ reported none.
The second challenge is deciding which conditions are sufficiently actionable to justify screening. "You only do screening if detecting it before it becomes clinically diagnosed leads to better outcomes," said Ned Calonge, a physician at the Colorado School of Public Health in Aurora and the outgoing chair of a disbanded advisory group that made newborn-screening recommendations in the United States.
Parental experiences and communication gaps
For parents, the effects of broad screening panels can vary drastically. For Dorka Nemes, the results were transformative. Her daughter, Safi Ford, participated in the UK's Generation Study and screened positive for isolated growth-hormone deficiency (搜索). Safi started growth-hormone therapy at just six months of age, whereas her mother was not treated until age 17, after much of the critical period for maximizing growth had already passed.
But not every family leaves satisfied. Drew Villano gave birth to a healthy baby boy, Harmony, in April, and enrolled in GUARDIAN shortly after delivery. Five weeks later, a genetic counsellor told her that her son carried a variant in a gene associated with Smith–Magenis syndrome (搜索). Villano said the genetic counsellor struggled to explain the significance of the finding over several phone calls and ultimately told her she could look up the condition online. Ultimately, more testing showed the variant was unlikely to be disease-causing, but the lack of clear, digestible explanations throughout the process left her shaken.
For Wendy Chung, a physician-scientist at Boston Children's Hospital, the promise of genomic newborn screening was evident long before she became a principal investigator on GUARDIAN. "Newborn screening is, I would argue, one of the most, if not the most, successful public-health initiatives in the sense that it leaves no one behind," she said. "GUARDIAN is really adding another modality to enhance what already is a very successful public-health initiative."
Yet optimism is tempered by practical questions. The process is currently costly and difficult to scale up for broader implementation, and some raise ethical questions about applying genome sequencing to thousands of people. "There's a lot of controversy around this," said Robert Green, including privacy issues and the potential for discrimination by insurance companies.