Genes Linked to Infant Brain Development

Expanding newborn screening (NBS) to include detecting genes linked to an increased risk of neurodevelopmental disorders (NDD) will do more harm than good, claimed a recent Paediatrics article.

The authors of the new article worry that increased genome sequencing would exacerbate existing health disparities, despite the fact that some experts think that identifying NDDs in the newborn period would be a reasonable method to identify and treat problems early.

“The benefit of early genomic screening hinges upon the ability to identify children with NDD early and then provide timely access to therapeutic supports,” said lead author, Sarah Sobotka, MD, assistant professor of Developmental and Behavioral Pediatrics at the University of Chicago. “The reality is that we’re practising in a context where there are few supports and disparate access to care for children already identified as having an NDD.”

Given the scarcity of genetics experts and diagnosticians in the United States, Sobotka and co-author Lainie Ross, MD, PhD, chairman of the Department of Health Humanities and Bioethics and director of the Paul M Schyve MD Centre for Bioethics at the University of Rochester, advocate for the strategic use of NDD screening on populations of children who exhibit signs of developmental delays.

Researchers have failed to demonstrate that genotype (genetic makeup) and phenotype (outwardly expressed indications or behaviour) are scientifically matched. This might cause concern and, in some situations, over-treatment of illnesses that may never manifest in a child.

Families may receive a diagnosis and label children based on the premise that a genetic variant means a child has an NDD or will develop one in the future. This can lead to stigma and self-fulfilling prophecy, causing harm to those who never display signs or symptoms.

Further exacerbation stems from the fact that there is an inadequate supply of trained therapists to provide the services needed for children with NDDs. Increasing early identification of those at risk who may never present with developmental delays would inevitably favour those with resources—children whose parents are more poised to advocate—widening the gap for minoritized groups who already struggle to access care.

The authors argue that our current body of genetic population data is also skewed because the majority of participants in genetic research have been members of the white middle class. This could naturally lead to more diagnoses for children in those groups—hence, quicker access to early interventions that would leave others who need urgent help behind, especially if they are in a minoritized group that has not yet been adequately studied.

Not only do we not have enough genetic diagnosticians to meet the demand for broad testing, but we also don’t have adequate genetic information about variants in diverse communities, Ross explained.

“If we wait to test the children until they manifest signs of delays, we can actually start looking for other genetic variants within those populations so when early genomic testing is proposed again in 10 or 20 years, we will have a better understanding of the extent to which these genotypes will correlate with NDD phenotypes,” said Ross, who is both a bioethicist and a paediatrician. “We’ll also have collected a much more diverse set of genotypes, so we will actually be looking for these differences in all populations.”

While Sobotka and Ross oppose broad genomic sequencing of newborns, they are not against early screening for NDD. They argue the best way to do that is not through universal NBS programs but focusing resources on early identification by general pediatricians during routine well-child visits by using standardized screening assessment tools as well as referrals from head-start programs or other early childhood education programs.

"We need to identify neurodevelopmental delays in children early,” said Sobotka, “and we need to provide enrichment opportunities, when possible, to prevent delays from developing.”

As Sobotka points out, such supports include not only educational interventions but also supportive family leave policies that encourage early parent-child attachment and parent-child interactive activities. “There are population-based interventions proven to improve neurodevelopmental outcomes that we are still not doing. These should be our first public-health initiatives; not expanding NBS.”