Genetic Test Detects More Abnormalities in AutismLast Updated: March 15, 2010. Although current testing guidelines for autism spectrum disorders recommend G-banded karyotype and fragile X testing, chromosomal microarray detects more genetic abnormalities and should be considered for diagnostic use, according to a study published online March 15 in Pediatrics.
MONDAY, March 15 (HealthDay News) -- Although current testing guidelines for autism spectrum disorders (ASDs) recommend G-banded karyotype and fragile X testing, chromosomal microarray (CMA) detects more genetic abnormalities and should be considered for diagnostic use, according to a study published online March 15 in Pediatrics.
Using G-banded karyotype, fragile X testing, and CMA, Yiping Shen, Ph.D., from Harvard Medical School in Boston, and colleagues performed genetic testing in 933 patients with ASDs.
The researchers found that G-banded karyotype yielded abnormal results in 2.2 percent of 852 patients, and fragile X testing yielded abnormal results in 0.46 percent of 861 patients. CMA identified deletions or duplications in 18.2 percent of 848 patients, although only 7.0 percent of 848 patients had clinically significant abnormalities. CMA detected clinically relevant copy number changes in 7.3 percent (with whole-genome coverage) and 5.3 percent (with targeted genomic regions) of patients.
"CMA had the highest detection rate among clinically available genetic tests for patients with ASD," Shen and colleagues conclude. "On the basis of our results, genetic diagnosis will be missed in at least 5 percent of ASD cases without CMA, and our results suggest that CMA with whole-genome coverage should be adopted as a national standard of care for genetic testing among patients with ASDs."