U.S. researchers looking for genetic changes linked to autism reported on Monday an advanced gene test that searches for deleted or extra DNA in chromosomes worked three times better than standard tests.
They said the test, known as a chromosomal microarray analysis or CMA, should be used in the first round of testing done to look for a genetic cause for a child's autism.
Autism is a mysterious condition that affects as many as one in 110 U.S. children. The so-called spectrum ranges from mild Asperger's syndrome to severe mental retardation and social disability, and there is no cure or widely accepted good treatment.
Standard genetic tests to look for chromosomal abnormalities and testing for Fragile X, the single largest known genetic cause of autism, often fail to detect anything, even though genes are responsible for up to 15 percent of autism cases.
The newer chromosomal microarray analysis test is far more sensitive. It searches the whole genome for places where chromosomes have been added, are missing or are in the wrong place. But because it is not recommended for the first round of testing, some insurance companies do not cover it.
"What we're hoping is to provide evidence to make it harder for insurance companies to say we don't want to pay for this," Dr. David Miller of Children's Hospital Boston, who worked on the study published in the journal Pediatrics, said in a telephone interview.