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Could whole-exome sequencing become a standard part of state newborn screening?

smiling baby boy

There are concerns about implementing whole-exome sequencing since it takes away the child’s right to decide if they want to know — or not — about their specific inherited disease.

It is still premature to standardize an innovative methodology known as whole-exome sequencing (WES) as part of state newborn screening programs, argues Beth A. Tarini, M.D., M.S., associate director for the Center of Translational Research at Children’s National Hospital, in a new editorial published in JAMA Pediatrics.

About 4 million infants are born annually in the United States. Newborn screening is a mandatory state-run public health program that screens infants for inherited diseases in the first days of life so they can receive treatment before irreversible damage occurs. Several of these screening tests are done on blood drawn from an infant’s heel.

WES holds the potential to screen infants for thousands of disorders and traits, including those that appear in adulthood. But there are concerns about implementing WES since it takes away the child’s right to decide if they want to know — or not — about their specific inherited disease. There is also the unknown effect that it could have on their ability to obtain health insurance.

“As caretakers for their children, parents have the challenge of deciding what kind of information, including genetic, will be valuable for their child,” says Dr. Tarini. “As a society, we have the responsibility of deciding where the healthcare dollars get the best return – especially when it comes to children. We need to start that conversation for universal genomic sequencing of newborns sooner rather than later.”

The Pereira et al. study, appearing in the new edition of JAMA Pediatrics and referenced in Dr. Tarini’s editorial, is the first to demonstrate no significant harm in the initial 10 months of life after performing WES under the best conditions of access to resources and a controlled environment.

While the Pereira et al. study has limited data on the effects of WES on families from underrepresented backgrounds, Dr. Tarini notes that it does provide a critical first step in this area of pediatric genomic research and for policy decision-making about the widespread implementation of WES in newborns.

“Moving forward, the U.S. will have to make a collective decision about the value of WES for newborns,” says Dr. Tarini. That value calculus cannot be made without consideration of the general state of healthcare for infants. As she points out, “This is not an easy question to answer in a country whose infant mortality ranks 34th according to the Organization for Economic Co-operation and Development (OECD).”

Dr. Tarini’s research identifies ways to optimize the delivery of genetic services to families and children, particularly newborn screening. She has also chaired state newborn screening committees and served on several federal newborn screening committees.

Newborn baby laying in crib

How a baby with classic galactosemia was nearly missed: When the test succeeds but system fails

Newborn baby laying in crib

Run at the state-level, mandatory newborn screening (NBS) programs detect a host of hereditary disorders so that infants can be treated before further damage, or even death, occurs.

Newborn screening (NBS) programs are critical to public health. Run at the state-level, mandatory NBS programs detect a host of hereditary disorders so that infants can be treated before further damage, or even death, occurs.

While much attention is paid to testing technology, programs must still meet basic minimum requirements to reliably identify and treat all affected individuals including minimum reporting requirements, case surveillance and a dedicated short-term follow-up program. In newborn screening, success is systematic.

A new report “How a baby with classic galactosemia was nearly missed: When the test succeeds but system fails,” published in the American Journal of Medical Genetics, takes a look at an individual case that almost slipped through the cracks of a local NBS program.

One disorder detected by NBS is classic galactosemia (CG), which arises from a deficiency in the galactose-1-phosphate uridyltransferase (GALT) enzyme, leaving infants unable to metabolize galactose-1-phosophate, a monosaccharide abundantly present in milk. CG can result in fatal liver failure, sepsis and coagulopathy if the affected infant is not switched to soy-based formula within the first week of life.

CG can be detected through a combination of enzyme assay, DNA analysis and galactose quantification. However, NBS programs differ in testing protocols for CG by state, and not all NBS programs conduct all of these tests. This is of particular relevance to the Washington, D.C., metropolitan area, a regional nexus where crossing state and district lines for medical care is common.

The report describes how a D.C.-born infant was screened for CG through all three tests. While his galactose levels were normal, his GALT was low and DNA testing revealed homozygosity for a CG mutation known as K285N. In tandem, the latter two indicators constitute a true positive result for CG, and necessitate the proper issuance of referrals, precautions and follow-up, which failed to occur in this case.

The infant breastfed and displayed notable lethargy, and parents were directed to a local emergency department in a neighboring state which does not screen for CG with DNA testing.

The providers there were unfamiliar with the DNA results, and after new labs came back normal, the NBS results were deemed as “likely falsely positive” for CG. Fortunately, a provider at the community hospital forwarded the NBS results to the Children’s National Rare Disease Institute (CNRDI). Upon review, CNRDI metabolic specialists immediately sought to rectify the situation by reaching out to the family with proper instructions and arranging a clinical evaluation, which occurred 10 days after birth.

While this case had a fortunate ending, the report highlights the potential deficiencies in NBS programs, which have historically been among America’s most successful public health initiatives. The proper and timely functioning of NBS systems is contingent upon the functioning of its constituent parts, including testing, diagnosis, follow-up, management and stakeholder education.

While test results were accurate in this case, systemic shortcomings left a patient in danger. As the authors state, “Programs must keep in mind that the true success of newborn screening extends beyond just the test itself…to improve safety and care outcomes we must focus on the system.”

A clinical report by a team of authors, mainly comprised of Children’s National clinicians, was published earlier this month in the American Journal of Medical Genetics. Authors include Sarah Viall, PPCNP, MSN, a pediatric nurse practitioner in the Rare Disease Institute; Nicholas Ah Mew, M.D., director of the Inherited Metabolic Disorders Program; and Beth A. Tarini, M.D., M.S., associate director of the Center for Translational Research.