Half were Children's patients who had their samples submitted to the hospital's DNA Diagnostic Laboratory, and the others were recruited through the Autism Consortium, a research and clinical collaboration of five Boston-area medical centers. Nearly half of the patients were diagnosed with autistic disorder, nearly half with PDD-NOS (pervasive developmental disorder not otherwise specified) and about 3 percent with Asperger disorder. Ages ranged from 13 months to 22 years.
Testing included the two currently used tests (G-banded karyotype and fragile X), as well as CMA. When the researchers compared the tests' diagnostic yield, they found:
Extrapolating from these results, the researchers estimate that without CMA, genetic diagnosis will be missed in at least 5 percent of ASD cases. CMA performed best in certain subgroups, such as girls with autistic disorder, and past studies indicate that it also has a higher yield in patients with intellectual disability (who constituted only 12 percent of this sample).
"CMA clearly detects more abnormalities than other genetic tests that have been the standard of care for many years," says Miller. "We're hoping this evidence will convince insurance companies to cover this testing universally."
In all, roughly 15 percent of people with autism have a known genetic cause. Establishing a clear genetic diagnosis helps families obtain early intervention and services for autism, and helps parents predict the possibility of having another child with autism.
In addition, by pinpointing bits of chromosomes that are deleted or duplicated, CMA can help resea
|Contact: Keri Stedman|
Children's Hospital Boston