New Genetic Testing Could Assist Autism Diagnosis in Children
Chromosomal microarray analysis and whole-exome sequencing may help detect genetic mutations potentially associated to the disorder.
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.
Scherer SW, et al. Molecular Diagnostic Yield of Chromosomal Microarray Analysis and Whole-Exome Sequencing in Children With Autism Spectrum Disorder. JAMA. 2015; 314(9):895-903.