Newer genetic tests like chromosomal microarray analysis and whole-exome sequencing for children with autism spectrum disorder (ASD) may help detect genetic mutations potentially associated to the disorder, a study published in JAMA reported.
There is currently inadequate research on the use of genome-wide tests to provide molecular diagnosis for patients with ASD. Stephen W. Scherer, PhD, of the Hospital for Sick Children, Toronto, and colleagues conducted chromosomal microarray analysis and whole-exome sequencing in unrelated children with ASD to determine the molecular diagnostic yield of these tests. All 258 children underwent chromosomal microarray analysis and a random subset (n=95) also underwent whole-exome sequencing. Detailed clinical assessments were performed for the presence of any major congenital abnormalities and minor physical anomalies. Children were categorized into three groups of morphological severity: essential, equivocal, and complex.
A total of 24 out of the 258 (9.3%) children received a molecular diagnosis from chromosomal microarray analysis, and eight out of the 95 (8.4%) from whole-exome sequencing. Of the children who underwent both types of testing, the estimated proportion with an identifiable genetic cause was 15.8%; this included two children who received molecular diagnoses from both tests. Children with ASD who had more complex clinical presentations had a higher clinical yield for genetic testing (37.5%).
“It seems likely that genetic testing of children with ASD will continue to increase, ” said the authors. “In a survey of parental interest in ASD genetic testing, 80% of parents indicated that they would want a sibling younger than 2 years tested to identify ASD-risk mutations even if the test could not confirm or rule out the diagnosis. For some children with positive genetic test results, treatment plans targeting ASD-associated medical conditions can be offered.”
A medical evaluation of children with ASD may help find populations more likely to achieve a molecular diagnosis with genetic testing, study authors concluded. “If replicated in additional populations, these findings may inform appropriate selection of molecular diagnostic testing for children affected by ASD,” they concluded.
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