'Remarkable' Lack of Genetic Testing in Autism

Megan Brooks

May 19, 2020

There is a marked disconnect between professional recommendations for genetic testing in autism spectrum disorder (ASD) and clinical practice.

A "real-world" study from Rhode Island showed that only 3% of individuals with ASD have undergone recommended clinical genetic testing.

"I had the impression that the frequency of recommended genetic testing was not going to be very high based on the patients I encounter clinically, but 3% is actually lower than I thought it would be," study investigator Daniel Moreno De Luca, MD, from Warren Alpert Medical School of Brown University in Providence, Rhode Island, said in a statement.

Addressing the barriers to testing is "crucial to enhance the implementation of genetic testing in clinical practice so that every person with ASD can receive optimal care," the investigators write.  

The study was published online May 13 as a research letter in JAMA Psychiatry.

Clinical Implications

ASD has a strong genetic component. Several medical professional societies, including the American Academy of Pediatrics and the American Academy of Child and Adolescent Psychiatry, recommend offering clinical genetic testing, including chromosomal microarray (CMA) testing and Fragile X testing, for patients diagnosed with ASD.

These tests can identify, or rule out, genetic abnormalities that could have implications in a patient's diagnosis and clinical care.

To gauge implementation of genetic testing in a real-world population, the researchers analyzed data from the Rhode Island Consortium for Autism Research and Treatment (RI-CART).

The cohort included 1280 toddlers, children, adolescents, and adults (age range 1 year to 68 years) with ASD confirmed via the Autism Diagnostic Observation Schedule, Second Edition (ADOS-2).

In total, 211 (16.5%) participants reported having received some genetic testing, including Fragile X testing in 169 (13.2%), karyotype in 92 (7.2%) and CMA testing in 57 (4.5%).

"Remarkably," the researchers note, only 39 (3%) individuals reported having received both recommended tests (Fragile X and CMA), whereas 121 (9.4%) "were unsure whether they had received any testing and 274 (21.4%) did not answer."

Factors associated with genetic testing included a younger age at diagnosis, more severe ASD and a higher frequency of intellectual disability and epilepsy. 

Patients diagnosed by subspecialist pediatricians were also more likely to undergo genetic testing as compared with those diagnosed by psychiatrists and psychologists.

Analysis by calendar year of ASD diagnosis showed that CMA testing increased, and Fragile X and karyotype testing decreased, over the last decade. 

The higher proportion of those undergoing CMA testing in more recent years is a "hopeful" sign, Moreno De Luca said. However, "there is still significant work to be done, especially for adults on the autism spectrum."

Comfort, Support

Commenting on the results for Medscape Medical News, Alexander Kolevzon, MD, clinical director of the Seaver Autism Center at the Icahn School of Medicine at Mount Sinai in New York City, said the results of this study suggest that the "vast majority of children with ASD in Rhode Island are unfortunately not receiving standard of care genetic testing."

"The reason more kids aren't tested is multifactorial and may relate to education for providers and perceived lack of access to appropriate testing," said Kolevzon, who is also director of child and adolescent psychiatry for the Mount Sinai Health System.

"Further, many physicians may be reluctant to order genetic testing, even if available, out of concern that they will not know how to interpret the results and do not know how to access specialized clinicians who do," he added.

Kolevzon, who was not involved with the study, said genetic testing in ASD is "critical" because it can provide a cause for the child's diagnosis in certain cases.

"When a genetic cause is identified, it can help predict recurrence risk in subsequent offspring, aid in medical assessment and monitoring, and eventually guide treatment or facilitate access to clinical trials. In addition, families often feel enormous relief in receiving a genetic diagnosis and can subsequently find comfort and support within a community of families with the same genetic syndrome," he said.

This work was supported by the Simons Foundation Autism Research Initiative, the Norman Prince Neurosciences Institute at Lifespan, the Hassenfeld Child Health Innovation Institute at Brown University, and the Robert J. and Nancy D. Carney Institute for Brain Science at Brown University.

Moreno De Luca and Kolevzon have disclosed no relevant financial relationships. Coauthor Eric Morrow has received grants from Simons Foundation/Simons Foundation Autism Research Initiative; other support from Norman Prince Neurosciences Institute at Lifespan, Hassenfeld Child Health Innovation Institute at Brown University, and Robert J. and Nancy D. Carney Institute for Brain Science at Brown University during the conduct of the study. Coauthor Stephen Sheinkopf reported grants from Simons Foundation during the conduct of the study.

JAMA Psychiatry. Published online May 13, 2020. Research Letter

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