Study finds chromosomal microarray analysis detects more abnormalities
MONDAY, March 15 (HealthDay News) -- A newer type of genetic test is better at detecting abnormalities that predispose a child to autism than standard genetic tests, new research has determined.
Researchers offered about 933 people aged 13 months to 22 years who had been diagnosed with an autism spectrum disorder three genetic tests: G-banded karyotype testing, fragile X testing or chromosomal microarray analysis (CMA), which has been available only for the past few years.
Karyotype tests identified chromosomal aberrations associated with autism in about 2 percent of patients, while the fragile X genetic mutation was found in about 0.5 percent of patients.
CMA detected chromosomal abnormalities in slightly more than 7 percent of patients, making it the best available genetic test for autism spectrum disorders, the study authors said.
"The CMA test alone has triple the detection rate of karyotyping or fragile X," said co-senior author Bai-Lin Wu, director of the Genetics Diagnostic Laboratory at Children's Hospital Boston. "CMA should be added to first-tier genetic testing for autism spectrum disorders."
The study appeared online March 15 and will be published in the April print issue of Pediatrics.
"When parents have a child diagnosed with an autism spectrum disorder, one of the first questions they often ask is 'how did this happen?' " said Dr. Robert Marion, a pediatric geneticist at Children's Hospital at Montefiore Medical Center in New York City.
"In the vast majority of cases, we believe there is at least a genetic predisposition to autism, but the ability to identify a specific genetic cause has been very elusive," Marion said. "Part of that is because of the technology that's been available. A larger part is at this point, we just don't fully understand what the genetic mechanism that le
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