Will a child who's evaluated for autism later develop an intellectual disability? Can this be accurately predicted? Early-childhood experts in Quebec say they've have come up with a way to better find out.
In a study of 5,633 children drawn from three North American cohorts, clinician-researchers affiliated with Université de Montréal developed a new predictive model that combines a wide range of genetic variants with data on each stage of a young child's development.
Their goal? To obtain reliable information as early as possible to predict the children's developmental trajectory and thus offer more proactive support to those who may need it - namely, parents trying to better understand and anticipate their child's needs.
Published today, the study marks an important turning point in the use of genomics data: instead of being used to explain a developmental condition that was previously observed, with the new method genetic testing is used to predict future development.
'Difficult to foresee the future'
"In some children, initial signs of autism can be observed as early as 18 months of age," said the study's first author Dr. Vincent-Raphaël Bourque, a PhD candidate at the Centre de recherche Azrieli du CHU Sainte-Justine, the mother-and-child hospital affiliated with UdeM.
But "it remains difficult to foresee the child's developmental trajectory over the medium and long term," said Bourque, who's also a senior medical resident in child and adolescent psychiatry at the Montreal Children's Hospital.
"Many parents wonder whether their child will develop an intellectual disability, which occurs in 10 to 40 per cent of autistic children, and only becomes apparent around the age of 6 to 8 years," he said.
Currently, doctors rely primarily on monitoring a child's early developmental milestones, such as acquiring language and walking, to predict their later development. However, these predictions are limited, especially for younger children. It's also uncertain how accurate these predictions are.
As a result, most doctors now simply wait and see how the child develops. Unfortunately, this can result in broadening the gap between a child's unique strengths and challenges, their increasing social and academic demands, and the support they and their family are offered, and cause high levels of stress.
A better approach, the study's authors say, would be to offer children earlier, more personalized attention and support. But to do that, doctors would need to foresee the challenges a child will experience, not wait until they're overwhelmed.
That's where the new model comes in.
10 per cent correctly predicted
Taking into account a large number of genetic variations-including some that are usually considered to have little predictive value-and combining them with data on each stage of language and motor development, the study was able to correctly predict 10 per cent of the occurrences of intellectual disabilities in the participating children.
Additionally, the researchers were twice as able to differentiate between low and high probabilities of intellectual disability in children with significant developmental delays.
These findings establish a benchmark and show promise for future predictions, the study's authors say.
"Research teams are constantly discovering new genetic variations, and computational models are becoming more and more powerful," said senior author Dr. Sébastien Jacquemont, a geneticist and researcher at CHU Sainte-Justine.
"So we can be sure that in the coming years, with cheaper and more readily available genetic testing, our ability to make accurate predictions will increase, allowing for more tailored medical care and support that will be accessible to more children."
The study pays special attention to measuring the degree of uncertainty - that is, how often predictions were accurate or inaccurate, which is key information when communicating with the children's families.
"As a medical practitioner, I think it is essential to explain to families the degree of certainty (and uncertainty) of our predictions," said Bourque. "It helps them to make better decisions with and for their child."
