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Molecular testing may identify genetic mutations related to ASD
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Chromosomal microarray analysis and whole-exome sequencing genetic testing may help to identify genetic mutations linked to autism spectrum disorder, providing potential diagnostic benefits for children suspected of having the disorder, recent study data suggested.
“Among a heterogeneous sample of children with [autism spectrum disorder(ASD)], the diagnostic yields of [chromosomal microarray analysis (CMA)] and [whole-exome sequencing (WES)] were comparable, and the combined diagnostic yield was higher among children with more complex morphological phenotypes,” Kristiina Tammimies, PhD, of the Center for Applied Genomics at The Hospital for Sick Children, Toronto, and colleagues wrote. “Our data suggest that medical evaluation of ASD children may help identify populations more likely to achieve a molecular diagnosis with genetic testing.”
The researchers compiled a cohort of 258 children with ASD, who were tested to define morphology scores based on the presence of major congenital abnormalities and minor physical abnormalities. Their assessment included review of medical records and family history, brain MRI scans, IQ testing, screening for birth defects and documentation of any minor physical anomalies. Each child then was assigned a minor physical anomaly score, and the cohort was classified by score in order of increasing morphological severity: essential group (0-3), equivocal group (4-5) or complex group (≥6). All children underwent CMA testing, while 95 underwent WES testing, which required participation from a full parent trio.
CMA testing revealed that 24 children received a molecular diagnosis (P < .001), while eight children who underwent WES testing received a molecular diagnosis (P = .02).
Study results also found that an estimated 15.8% of the children who underwent CMA and WES testing had an identifiable genetic etiology (P = .001).
“It seems likely that genetic testing of children with ASD will continue to increase,” Tammimies and colleagues wrote. “For some children with positive genetic test results, treatment plans targeting ASD-associated medical conditions can be offered.”
In a related editorial, Judith H. Miles, MD, PhD, of the University of Missouri, reinforced the value of the findings presented by Tammimies and colleagues.
“Foremost, the data indicate that physicians responsible for children with ASD should arrange access to a genetic evaluation using techniques that have the best chance of determining an etiologic diagnosis,” Miles wrote. “It is incontrovertible that precise diagnoses pave the way to better medical care, improved surveillance, better functional outcomes, and informed genetic counseling, often with the possibility of prenatal or preimplantation diagnosis.” – by David Costill
Disclosure: Tammimies reports no relevant financial disclosures. Please see the full study for a list of all other authors’ relevant financial disclosures.
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